BIOL 203 Nutrition Class Notes PDF

BIOL 203: Nutrition Class notes Friday, September 6th 2024: - 4 master chef activities: The first one is due October 1st. Take pics of raw ingredients and then the finished meal. - 2 midterms: 15% each Lesson 1: Introduction to nutrition READINGS: what is food: preface + chapter 1 Nutri...

BIOL 203: Nutrition Class notes Friday, September 6th 2024: - 4 master chef activities: The first one is due October 1st. Take pics of raw ingredients and then the finished meal. - 2 midterms: 15% each Lesson 1: Introduction to nutrition READINGS: what is food: preface + chapter 1 Nutrition: how an organism acquires food and uses food to support all processes required for its existence. The science of human nutrition is the study of the nutrients and other substances in food and the body’s handling of them. - The science of human nutrition is a young science. More recently, it has a sister discipline known as nutritional genomics. Lesson 1.3: What is Food? - The science of nutrition is partly to blame for any of these eg: poptarts, soda, milkshakes, sprinkles etc to be considered as food. - Food has been broken down into an amalgam of nutrients, and that we need x amount of these nutrients everyday. - Food is much more than just vitamins and minerals. Food and eating is a deeply satisfying activity that we engage in at least three times per day. - Organs of the digestive system communicate with the brain to offer a feeling of wellness and satisfaction. Food provides us with essential nutrients. - Essential nutrients must be supplied by the diet because the human body cannot synthesize them. It technically can, but not in sufficient quantities. The absence of an essential nutrient would lead to deficiency disease and eventually death. However, too much can lead to chronic diseases or sudden deaths as in overdosing. - But food doesn't only supply essential nutrients, other nutrients called non-nutrients like (reduce the risk of colon cancer, promotes bowel health) and phytochemicals (function as antioxidants) 1. Energy yielding nutrients: - Carbohydrates - Lipids  - Proteins 2. Non energy yielding nutrients: - Vitamins - Water - minerals Lesson 1.4: The challenge of choosing food - We can split our choices into a simple dichotomy: processed foods vs whole foods. - Factors that drive food choices are: social network, convenience, emotional comfort, beliefs, economy. - What does psychology have to do with eating: well, we all believe in healthy eating yet we behave differently. This is because of cooking skills and the lack of knowledge on nutrition. Lesson 1.5: Cooking - People in our society cook less and less. This is because we tell ourselves we don't have the time, arent good etc. So, it's the multi billion dollar corporations like General mills, Campbell Soup who do the cooking. - Some rules to follow for cooking: food safety, discipline, stay organized and stay away from kitchen gadgets. - “If you eat well, by extension you live and love better” Laura Calder Lesson 2: Nutrient standards and guidelines: READINGS: what is food: chapter 2 Introduction: this lesson will focus on dietary reference intake (DRI), the four major food groups and looking at food guides. The goal is to understand the food groups and food guides of countries to make better choices with the foods we eat. DRI are what supports the food guides, eg: 90mg of vitamin C equals 7 servings of fruits and vegetables. Lesson 2.2: Dietary Reference Intakes (DRI) - DRI are defined as Reference values that are quantitative estimates of nutrient intakes - Used for planning and assessing diets for healthy people. In the past: - The purpose of DRI was to reduce risk of deficiency disease like scurvy or beriberi disease. Today: - The purpose of DRI is to reduce chronic diet related diseases like type 2 diabetes. Main objectives of DRI: 1. Prevent deficiency diseases: - Amount of a nutrient needed to prevent the deficiency disease in healthy people. 2. Reduce risk of chronic diseases; - Amount of a nutrient needed to reduce the risk of developing chronic diseases. 3. Safety supplement use and fortification: - Upper safety level for nutrient intake Nutrient Intake Standards: Group 1: most nutrients → a,b,c target deficiency diseases while d targets supplement use a) Estimated average requirement (EAR) - Defined as the average daily intake level of a nutrient to meet the needs of half of the healthy people in a lifestage or gender group. Based on a diagnostic test that measures adequate amounts in the human body. It is a requirement, not a recommendation. b) Recommended dietary allowance (RDA) - Defined as the average daily nutrient intake level that meets the needs of 98% of the population in a lifestage or gender group. - EAR multiplied by some factor = RDA c) Adequate intake (AI) - Based on intake levels of a healthy group of people in a particular life stage and gender group. We find a population that is fairly healthy and examine their intake level and base the adequate intake on that number. Eg: taking the daily intake of a friend who seems and looks healthy and basing your diet on them. d) Tolerable upper intake level (UL) - Maximum daily amount of a nutrient that appears safe for most healthy people. Above this level is an increased risk of several health effects. Meant to avoid excesses, especially when using supplements. → summary of the DRI: x axis = intake of essential nutrients. Y axis = degree of health. On both ends, death can happen because you have too much or too little. Below RDA can lead to deficiency, the degree of health increases as we increase the RDA. Optimal intake is in the middle. Group 2: energy and macronutrients → target carbs, lipids and protein intake. They deal with calorie intake. a) Estimated energy requirement (EER) - Represents the number of calories that maintain energy balance in a healthy person. The EER is an individualized estimate. b) Acceptable macronutrient distribution ranges (AMDR) - Defined as the ranges of intakes for energy-yielding nutrients that provide adequate energy and nutrients and reduce the risk of chronic disease. Energy intake can be obtained from carbohydrates, lipids and proteins. It's recommended that 45-65% energy intake comes from carbohydrates, 20-35% from fats and 10-35% from protein. Lesson 2.3: Who uses DRIs? - Nutrition experts known as registered dietitians. - General practitioners generally refer patients to a registered dietitian. - Outside of healthcare, the food industry: canadian food inspection agency. (CFIA), - The nutrition facts table must include 13 core nutrients. The percent daily value (%DV) is based on a 2000 calorie diet. Lesson 2.4: Major Food Groups - In Canada, we find 4 major food groups: 1. Grains: - Grains are seeds. Contains a plant embryo also known as a germ. The germ receives its nourishment from the carbohydrates stored in the endosperm. The seed is protected by the fibre rich outlet layer known as the bran. These 3 parts make up every seed including grains. - Grains are rich in: carbohydrates, fibre (rich only when the grain is whole), vitamins: folate, thiamin, riboflavin, vitamin E and minerals like magnesium and iron.  - A grain is fibre-rich only when it is whole. The germ contains vitamins and minerals. The endosperm is mostly starch and the bran contains most of the fibre. - Grains all belong to a single plant family known as grass family. (oat, wheat, rice). 2. Milk & alternatives: - Includes milk and milk products that retain their content of the mineral calcium. - Foods in this group are fortified with vitamin A and D, protein, vitamins like riboflavin, B and B12 and minerals like calcium. - Milk remains an excellent source of protein, vitamins and fats. The enzyme required to break down milk emerged 10,000 years ago. 3. Meat & alternatives: - Provides a rich source of proteins, vitamins B6 and B12 and minerals like iron and zinc. - Meat is defined as the flesh of goat, beef, pork. Poultry is defined as birds, chicken, duck. The alternatives include legumes, eggs, nuts and seeds. These alternatives provide a lot of protein and fibre. - These alternatives all have one thing in common: all food for an embryo! a) Legume Family: - Beans, peas and lentils all belong to the legume family. These seeds, like the grains, are tiny energy packets made for the nourishment of the developing embryo. - Peanuts are also members of the legume family. They are also in a pod. This makes sense why people who are allergic to peanuts may also be allergic to legumes. Tree nuts are not members of the legume family. All a source of protein. 4. Vegetables & fruit: - Includes vegetables, fruits, 100% fruit juice and 100% vegetables juice. Can be fresh, frozen or canned. - Carbohydrates, fibre, vitamins, minerals. - Anything that contains a seed, means it's a fruit. Lesson 3: Basic Chemistry and Organ Systems READINGS: what is food: chapter 3 Introduction: we will be defining what is matter, atoms, elements, molecules, ions and compounds. Topics include solutions, solubility, enzymes and the pH scale. The last point is the digestive system and the circulatory system: how the body circulates nutrients. Lesson 3.2: From Atoms to Compounds: Matter: is anything that takes up space. The smallest unit of matter is the atom. - Molecule: atoms come together to form chemical bonds in a stable arrangement which is called a molecule. When a molecule has 2 or more elements, it's called a compound. Ex: carbon dioxide is a compound, but oxygen gas is a molecule because it only contains a single element. - Covalent bonds: strongest of all bonds, share electrons - Ionic bonds: donate electrons. Lesson 3.3: Solutions, Solubility, Enzymes and the pH scale: - A solution is a homogenous mixture of two or more compounds. The major component is the solvent, the minor component is the solute. Blood capillary: tiniest of blood vessels, as blood rushes through the capillary, the plasma is forced out of tiny openings and puls around the cells of your body. This cell is now bathed in this fluid (water, nutrients), cells can now take up these nutrients to meet their cellular needs. - Polar molecules are molecules with partial charges created by electronegative atoms. They interact with other polar molecules to form weak hydrogen bonds. - Enzymes are proteins and this easily dissolves in solutions, in the absence of enzymes, absorption of nutrients would be impossible. Ex: lactase binds to the milk sugar known as lactose and breaks it down. - The pH of fluids is crucial to activate enzymes to facilitate digestion. An enzyme that works to digest food in your mouth will not work in your stomach due to change in Ph causing the enzyme to change shape. pH of saliva is 6.4, 1.0 in your stomach and back up to 8.0 in your intestine. The pH is a measure of the concentration of hydrogen ions (H+). 0-14, 0 being very acidic and 14 being very basic. Lesson 3.4: The Digestive System: a) There are 4 types of tissues: → these 4 tissues come together to form organs. 1. Epithelial: - The lining of the entire alimentary canal is made up of epithelial cells. It allows the smooth passage of food, synthesizes and secrete enzymes for digestion and absorbs nutrients. 2. Connective: 3. Muscle: 4. Neural  → the digestive system is simple, it's a hollow tube from end to end (mouth-anus) made up of lumen. The organs include: the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus. The accessory organs are the salivary glands, the pancreas, gallbladder and the liver. - The functions of the digestive system: - digestion, absorption and elimination. Functions aided by epithelial cells make up the innermost lining of the digestive tract. The substances released are enzymes, hormones and mucus. a) The mouth and stomach: - Perform both chemical and mechanical breakdown of food. Muscular contractions churn the food. The salivary glands secrete saliva to begin the process of digestion. - The longitudinal muscle layer overlays circular diagonal sheets. As those sheets of muscle contract, food churns. Enzymes mixed with stomach secretions and food becomes chyme. Teaspoons of chyme at a time slowly move into the small intestine. b) The small intestine: - Circular folds around the lumen have these tiny finger-like projections called villi. Each villus is penetrated by two types of vessels: blood vessels and lacteal vessels. Villi lined with epithelial cells help nutrients absorb quickly. It is a sheet of epithelial cells. The digestive system meets the circulatory system: - Absorption is the transfer of nutrients from the gastrointestinal tract into the blood or lymph vessels. The accessory organs are all connected. The small intestine is in direct contact with the gallbladder and the pancreas. Substances produced in the liver and gallbladder travel through tiny ducks and are released into the duodenum. Elimination and gut flora: - Solid waste is removed from the body, through the large intestine. The large intestine absorbs water and some minerals. Microbes sustain themselves by feasting on fibre. Probiotic foods are good for the intestine, yogurt, and fermented dairy products. Lesson 3.5: The Circulatory System: - The heart acts as the pump for the blood to keep moving through the system. The network of blood vessels includes: arteries, arterioles, capillaries, venules and veins. The red = oxygenated blood, blue = deoxygenated blood. - Nutrient exchange between blood and the cells of the body: tiny capillary, cells neighbour this ruptured vessel. Ex: a paper cut is splitting open a small capillary, this blood on the surface of your skin contains the nutrients from your most recent meals. Lesson 4: Carbohydrates READINGS: what is food: chapter 4 Introduction: the goal of this lesson is the types of carbohydrates (simple and complex), alternative sweeteners, the digestion and absorption of carbohydrates, carbohydrates and disease and carbohydrates and DRIs. Lesson 4.2: Calories: - The sun's energy is stored in the glucose molecule. When you need energy, your cells breakdown glucose and release the energy stored in the carbon hydrogen bonds. The carbon dioxide you exhale is what remains of glucose. - The energy content of food is measured in calories. Calorie is a unit that measures heat energy. - Energy is stored within the C-H bonds. We've got: Small calorie, big Calorie and the kilocalorie. 1000 calories = 1 calorie = 1 kilocalorie 1. calorie:  - Heat energy needed to raise the temperature 1g of water 1 degree celsius. It would be too hard to use this as a measurement. 2. Calorie (the Big calorie): - We label the energy content of food with a big calorie. It's the same as a kilocalorie. 3. Kilocalorie: - Heat energy to raise the temperature 1000g of water 1 degree celsius. Lesson 4.3: Simple Carbohydrates & Non-nutritive Sweeteners: - Understanding simple carbohydrates, glucose, fructose etc. A) Monosaccharides: - All have the same chemical formula (C6 H12O 6 ) Glucose, Fructose and ose. The only difference is the arrangements of the atoms, this changes the degree of sweetness in each. 1. Fructose: - Taste the sweetest - Found in fruits and honey 2. Glucose: - Middle sweetness - fruits, vegetables - Most important monosaccharides. The dominant sugar in the body and dominant energy source for red blood cells.  3. Galactose: - Not very sweet. - Found in milk. B) Disaccharides: - This is a pair of sugar molecules. 1. Galactose pairs with glucose to make lactose (galactose + glucose = lactose) that's why we call it milk sugar. 2. Glucose pairs with glucose to make maltose. It's a by-product of starch digestion. (sweet potato) 3. Glucose pairing with fructose to make sucrose (table sugar). Sugar cane plants store sucrose in the stalk. This is honey etc. raw sugar, brown sugar, table sugar is all sucrose. (glucose, fructose or sucrose is not toxic, it's a source of energy for cells, plants and animals dependent on simple sugars for growth and reproduction.) - Non- nutritive sweeteners are sweeter, and give no energy. Sugar alcohols are not fully absorbed by the intestinal tract: gums, breath mints etc. Lesson 4.4: Complex Carbohydrates: - Made of hundreds of glucose molecules linked together in straight or branched chains. Starch is the storage form of glucose in plants, we then absorb glucose and build glycogen which is the form of glucose in the body. Fibre includes soluble and insolubles.  - Plants store glucose in the form of starch. Starch is then stored in the body for later use. Found in grains and legumes. Depending on how the starch is stored, it has different properties. For example: corn starch, tapioca starch, wheat starch, arrowroot. A. Starch: two types Amylopectin: - Branched type of starch - Quickly digested to glucose Amylose: - Single linear thread of glucose molecules - Slowly digested to glucose B. Glycogen: Animal Starch - We absorb glucose, this then travels to the liver and muscle cells and is stored as glycogen. When we need energy, the liver breaks down glycogen to release glucose into the bloodstream. - When we exercise, our muscles break down glycogen to release glucose for energy. C. Fibre: two types Soluble: - Dissolve in water - Prized by the food industry for their thickening ability. (pectins, guar gums) - Are fermented by bacteria in the large intestine PROS: - Slow gastric emptying, slow glucose intake, trap cholesterol and carry it to the large intestine for elimination, improve bowel health, reduce risk for cardiovascular disease, type 2 diabetes, obesity, colon cancer. - Prebiotic food is soluble fibre. Insoluble: - Do not dissolve in water - Are not fermented in large intestine - Do not form gels PROS: - Promote bowel health, crucial to maintain healthy bowel by preventing diverticula, promotes fast transit. Lesson 4.5: Digestions and absorption of carbohydrates: - Digestion of carbohydrates involves the breaking down of starch and disaccharides into monosaccharides, mostly glucose. The digestion starts in the mouth with saliva and continues in the small intestine with the following enzymes: maltase, sucrase, lactase and pancreatic amylase. - Lactose intolerant: inability to produce enough lactase causing the inability to digest lactose. The bacteria in the large intestine break down lactose and produce irritating gases and acids resulting in abdominal discomfort. Lesson 4.6: Carbohydrates and Diseases: - After a carb-rich meal, blood glucose levels can rise quickly. Leading to hyperglycemia or high blood sugar. 3 types of diabetes: 1. TYPE 1: - Autoimmune disease - Cells in the pancreas that synthesize insulin are destroyed - Must eat healthy meals & daily injections of insulin 2. TYPE 2: (most common) - 90% of people with diabetes have type 2 - Diet related chronic diseases - Poorly controlled type 2 leads to pancreas shutting down 3. GESTATIONAL: - A form that may occur during pregnancy. Lesson 5: LIPIDS READINGS: what is food: chapter 5 + nutrition for healthy living: chapter 6 Introduction: in this lesson we learn about the lipids family: fatty acids, triglycerides, phospholipids and cholesterol. We also look at the digestion and absorption of lipids and diseases. Lesson 5.2: Ode to Lipids in Food and in the Body 3 main reasons why lipids are necessary: 1. Enhance Flavour: 2. Increase intestinal absorption of fat-soluble vitamins and phytochemicals 3. We need at least 20g of fat to properly absorb fat-soluble vitamins. → fat cells - adipose cells: fat works like soft body armour, it protects the viscera and bones from breaking when we fall. Fat is a type of connective tissue that supports other tissues. → fat provides a major source of energy, providing more than twice the energy from carbs and proteins. Lipids are the only form of energy that is stored for prolonged periods of time. We store energy mostly as fat and not glycogen. Visceral fat and subcutaneous fat: a) Subcutaneous Fat: located below the surface of the skin, helps maintain body heat and cushion the body. As we age, it helps us protect from shattering our bones, however too much subcutaneous fat can lead to cardiovascular disease. b) Visceral Fat: a fatty apron that covers and protects abdominal organs. Lesson 5.3: Types of Lipids in Food and in the Body Types of Lipids: - Fatty acids - Triglycerides - Phospholipids - Cholesterol A. Fatty Acids: - Chain of carbon atoms attached to hydrogen atoms. Fatty acids contain a methyl group at one end and an acid group at the other. - (Short chain FA: 2-4 carbons long), (Medium chain FA: 6-12 carbons long), (Long chain FA: 14-24 carbons long) - Some fatty acids are straight, some are bended  - Fatty acids with NO double bonds = saturated. It is saturated with hydrogen atoms, no double bonds within the carbon chain. - Fatty acids with one or more double bonds IS unsaturated. A fatty acid with a one double bond is called a monounsaturated fatty acid (MUFA). c=c. MUFAS have only one double bond meaning molecules are more packed together, making oils If it has two or more double bonds, it is called a polyunsaturated fatty acid (PUFA). c=c + c=c. - The saturation level also determines the behaviour of the lipid. These sticks stack neatly and tight next to each other which is what remains butter solid at room temperature. However, oils are lipids that are liquid at room temperature composed of unsaturated fatty acids. Broken sticks form an unorganized mess preventing the lipids from stacking nicely. - The carbon atom of the methyl group is called the end of the molecule, called the omega end. To identify the fatty acids you: EXAMPLE: 18= how many carbon there are total. 2= how many c=c there are. w= how many carbon between the equal sign. Omega 3 & 6: - We cannot synthesize fatty acids, they are essential nutrients, we need them and cannot synthesize them. They must be supplied by the diet. ç - Omega 6: easily reached by diet. - Omega 3: few foods supply it, those that do are expensive. There are 3 types of omega 3 fatty acids: → Linolenic acid: walnuts → Docosahexaenoic acid (DHA) + Elcosapentaenoic acid (EPA): mostly in fish - DHA: proper brain function, essential for the development of the brain, maintenance of normal brain function, improves learning ability. - EPA: lowers blood pressure, reduces blood clots, protects against irregular heartbeats, reduces inflammation and overall protects cardiovascular health. Trans Fatty Acids (TFA): - These come in 2 shapes. If the hydrogen atoms are on the same sides of the carbon chain, it's called a cis formation. If they are on opposite sides, it's called a trans formation. - All trans fats are man made through a process of hydrogenation, this results in unsaturated fatty acids behaving like saturated fatty acids. For example ,margarin is over 50% trans fat. Products in trans fats have a longer shelf life. CONS OF TRANS FAT: - Lead to cardiovascular issues, causes heart diseases Conclusion on fatty acids:  - The difference in length and shape make some fatty acids beneficial while others are near lethal. Some improve brain function and some lead to cardiovascular diseases. B. Triglycerides: - Most common lipid found in our food. 95% of what we eat is in the form of triglycerides, 99% of the fat in our bodies is stored as triglycerides. - Can have varying amounts of saturated, monounsaturated and polyunsaturated fatty acids. The fatty acids are attached to glycerol molecules. - Fats and oils are triglycerides. Each fat or oil molecule contains 3 fatty acids: saturated MUFA or PUFA. EXAMPLE: compare triglyceride composition of olive oil and corn oil, what is the difference in consistency between olive oil and corn oil? Which is thicker? - Olive oil is thicker because it contains 74% MUFA compared to just 24% MUFA in corn oil. Because monounsaturated fatty acids are less bent than PUFAS, the oil appears thicker. - Saturated and monounsaturated fatty acids are more heat stable because they have fewer than one double bond. C. Phospholipids: - Are chemically similar to a triglyceride except they carry two fatty acids. They are also called diglycerides with a polar end attached to two non-polar hydrocarbon tails. - Are partially water soluble. Phospholipids make up the cell membrane of all living organisms. - They differ by: one: the length and shape of fatty acids and two: an additional compound that is joined to the phosphate. - The most common phospholipid is lecithin. - Diglycerides are also a key ingredient in the kitchen, they ask as an emulsifier. For example, when making mayonnaise you add oil and egg which break down the oil. D. Cholesterol: - Found only in the animal kingdom, like eggs, dairy, meat, fish. - Lean meats, low or reduced fat dairy have little cholesterol. - It is not an essential nutrient, the liver produces it alone. FUNCTIONS IN THE BODY: - Cholesterol is necessary for synthesis of estrogen and testosterone. - Has a role in digestion/absorption of lipids and its vitamin D synthesis. Lesson 5.4: Digestion and Absorption of Lipids Chemical and mechanical digestion of lipids: STEP 1: Start in your mouth, the warmth begins to melt fat along with lingual lipase. Chewing and churning mechanically breaks apart the fat. STEP 2: The bulk of chemical digestion of lipids is accomplished in the small intestine with the help from the accessory organs. Epithelial cells release hormones to alert accessory organs of the arrival of lipids STEP 3: Now that the accessory organs have received the arrival of lipids, the gallbladder releases bile, which contains cholesterol, salts and lecithin (a phospholipid). The bile breaks down the large lipid globules into smaller bits called micelles. Lesson 5.5: Lipoproteins: - Lipoproteins contain triglyceride, phospholipids, protein and cholesterol. Everything inside these “golf balls” are non polar, allowing it to dissolve in water. - Four types of lipoproteins: 1. Chylomicrons: transport dietary triglycerides 2. Very low density lipoproteins (VLDL): product of the liver, the liver converts extra glucose into fatty acids and packages them into VLDL for delivery to fat cells. They also contain mostly triglycerides, they then become low density lipoproteins. 3. Low density lipoproteins: (LDL): composed of cholesterol, deliver cholesterol to cells. This is bad cholesterol. 4. High density lipoproteins (HDL): synthesized in the liver, mostly protein. Good kind of cholesterol. ↳ your blood contains varying amounts of all 4 of these lipoproteins. Each one secretly concealing lipids like a trojan horse. Lesson 5.6: Lipids, Diseases and DRIS: Cardiovascular disease is the disease of the heart and blood vessels. Coronary heart disease is the most common. - CVD begins with inflammation of blood vessels due to an excess of LDL, excess glucose or cigarette smoke. Immune system responds to the inflammation causing a plaque deposit in the blood vessels. Depending on the location of the plaque buildup, different organs can be affected (heart, kidney, brain). - Heart attack is the death of cardiac muscle tissue resulting from blockage of one or more coronary arteries. Arteries supply oxygen to heart muscles, if they become blocked they can’t reach the muscle cells causing the heart to stop. - Stroke is death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head. REDUCING RISK OF CVD: 1. Increasing soluble fibre intake 2. Limit your fat intake 3. Increase omega 3 fatty acid intake. Omega 3 has anti-inflammatory effects on the body. 4. Prescription drugs if lifestyle changes don't work. (statins) Lesson 6: PROTEINS READINGS: what is food: chapter 5 + nutrition for healthy living: chapter 7 Introduction: energy yielding molecules. We will look at the protein structure, protein function, protein synthesis in the body, digestion and absorption, proteins and diseases and protein in food and DRIS. Lesson 6.2: Protein Shape and Function: - Are energy yielding nutrients and chemically similar to carbohydrates and lipids. - Amino acids are the building blocks of proteins. Protein is a chain of amino acids, like a chain. The covalent bonds that link the amino acids are called peptide bonds and the long chain is called a polypeptide aka protein. There are 20 different amino acids, each with its own side chain: amino acids have 3 parts: 1. Amino group: contains a nitrogen atom, it's a precious atom 2. Acid group: backbone of all amino acids. 3. Side group: the functional group. - Of the 20 amino acids, 9 are essential and must be supplied by the diet, 11 can be synthesized by the liver. WE NEED ALL 20!  -Tables sort the amino acids by polarity. The absence of oxygen causes amino acids to be non polar, meaning no hydrogen blocks. - Protein shape is determined by the sequence of amino acids along the chain. Changes to the environment of a protein, it may break apart hydrogen bonds causing the protein to unfold. Unfolded protein is denatured and no longer functional. - A change in temperature or pH can cause the protein to denature. In food, a denatured protein changes the texture and in the body, denatured protein is no longer functional. For example: milk and lemon juice, the milk will curdle. - Muscle tissue is made up of protein, collagen is a protein. The muscle fibres are arranged in bundles and those bundles are held together by collagen. FUNCTION OF PROTEIN: - Provide structural support and movement (collagen & keratin are key structural proteins) - Work as enzymes & hormones (enzymes work to digest food in mouth, stomach and small intestine) insulin is a hormone and a protein. - Maintain fluid balance, regulate pH of fluids (plasma proteins are necessary for maintaining the right amount of fluids within your tissues) - Source of energy - Antibodies are proteins (without sufficient protein, the immune system lacks the virus fighting). Lesson 6.3: Protein Synthesis in the Body: - When we eat protein, digestion breaks them down by amino acids. They then absorb and deliver cells to the body. DNA supplies the instructions for making proteins. Protein synthesis: - Protein gives cells their characteristic shape and function. Our bodies contain over a trillion cells: nerve cells, epithelial cells and fat cells. - Inside each cell there's a nucleus which contains DNA. different proteins are being built. Then, your DNA will tell your cells the sequence of amino acids to form a protein. - Protein synthesis cannot proceed when amino acids are missing (due to poor diet). When this happens, protein synthesis comes to a screeching halt, the partially made polypeptide chain is dismantled and its amino acids are returned to the pool. Lesson 6.4: Protein Digestion & Absorption: a. Stomach: - HCI denatures food protein - HCI also activates pepsin  b. Small intestine: - Pancreas secretes more protein-splitting enzymes - Amino acids are the end products of protein digestion. After being absorbed, amino acids enter the hepatic portal vein and travel to the liver and the rest of the body. Protein digestion is very efficient. Lesson 6.5: Protein Turnover & Nitrogen Balance: - The recycling of protein is known as protein turnover. - For example: hemoglobins, they deliver oxygen to the cells of the body. They have short lifespans, meaning that once they are destroyed, hemoglobins are recycled and used elsewhere. Nitrogen Balance: protein is 16% nitrogen and this element is crucial for the synthesis of many other compounds in the body. Nitrogen equilibrium: We constantly need this amount of elements in our body. Healthy adults meet protein and energy needs. Intake + Retention = losses Intake: from food (dietary protein) Retention: protein turnover (recycling amino acids) Losses: nitrogen losses in urine (from breakdown of amino acids, in feces and sweat) 1. Positive nitrogen balance: Sometimes, you can be in positive nitrogen balance. This occurs during: pregnancy, lactation, resistance exercise, growing children, recovery from illness. Intake + Retention > losses  2. Negative nitrogen balance: occurs during starvation, emotional trauma or other traumas. Inadequate protein intake or digestive tract diseases that interfere with protein absorption. During this time, the body breaks down muscle protein and other protein for energy. Intake + Retention ﹤ losses Proteins as energy source (deamination): - If carbs and lipids are lacking, the body will sacrifice protein to get energy, this is known as deamination. The removal of the amino group will lead to a carbon skeleton which is used to make glucose or lipids. Therefore, if you eat too much protein, your liver will deaminate it and you will store it as fat. Lesson 6.6: Protein and Diseases: Allergies: - Allergies are hypersensitive responses to substances. Pollen allergies and food allergies are the most common. Pollen allergies are caused by an immune hyper-sensitive response to protein on the surface of pollen grains. - Food allergies are caused by an immune hypersensitive response to protein in certain foods. Most common are peanuts, tree nuts, milk, eggs, fish, shellfish, soy and wheat. Most allergic reactions are mild like a cough, runny nose, and sneezing. However, some allergies, especially in children can be severe, leading to anaphylaxis. Celiac: - An autoimmune disorder that affects the small intestine. Damage to the villi is caused by a hyper-sensitive immune response to gluten - a protein found in wheat and related grains. Treatment is to eliminate gluten altogether. Lesson 6.7: Protein in Food and DRIs: How much protein do we need? The EAR = 0.66g of protein/kg of body weight The RDA = 0.8g of protein/kg of body weight Intake amount increases during: - Pregnancy - Breast-feeding - Infancy & childhood - Recovery from serious illness - Blood losses - burns High quality protein: influence by 2 factors: 1. Amino Acid composition: contains all essential amino acids in adequate amounts 2. Protein digestibility: a measure of the amount of amino acids absorbed from a given food. → a high quality complete protein has all essential amino acids and are well absorbed. EX: meat, fish, poultry, eggs, milk → a low quality protein lacks amino acids and is not well absorbed. EX: plant protein/legumes, they lack 2 essential amino acids Protein complementation: - The process of mixing incomplete plant-based protein sources to provide all essential amino acids without adding animal protein. (legumes, grains) Lesson 7: VITAMINS READINGS: what is food: chapter 7 + nutrition for healthy living: chapter 8 Introduction: defining features of vitamins, fat soluble vitamins, water soluble vitamins and their functions, deficiency, diseases etc. Lesson 7.2: Defining Features of Vitamins: - Non-energy micronutrients. Our cells do not metabolize micronutrients for energy. However, many vitamins and a few of the minerals participate in the chemical reactions that release energy from macronutrients. - Vitamins are complex organic compounds. They are made up of carbon, hydrogen, oxygen and sometimes nitrogen and sulfur. Vitamins are NOT chains of repeated units, they look different from macronutrients. - They are natural and synthetic sources of vitamins. 1. Natural: - Plants, animals, fungi & bacteria. For example, mushrooms are a source of nutrient dense food. 1 cup of mushrooms contained 11.2 of folate. 2. synthetic: - Supplements and used as enrichment in food. a) Enrichment: addition of vitamins and minerals to food products to replace those lost during processing. b) Fortification: addition of supplementary nutrients to food that were either not originally present or present in insignificant amounts. Vitamin Solubility: - Vitamins are generally classed in terms of solubility. Water soluble vitamins: - Vitamin C & B. - Absorb directly into the blood - Travel freely - Circulate freely in water-filled compartments of the body - Kidney detects and removes excess urine. - Oranges, fruits Fat soluble vitamins: - Vitamins A, D, E & K - Absorb first into the lymph, then to the blood - Many require transport proteins - Stored in the cells associated with fat like fat cells and the liver. Can accumulate in the body and cause toxicity. - Oils, nuts, fatty foods. Absorption of Vitamins: - Your age, gender and diet will all differ how you absorb nutrients. Children need a lot more vitamins than adults to keep up with their fast metabolism. Pregnant women too. - Depending on how the food was processed, will also depend on the absorption. Like raw, processed or cooked. Lesson 7.3: Fat-Soluble Vitamins: 1. Vitamin A: - Vitamin A and beta carotene are found in several forms: retinol, retinal and retinoic acid. Retinol is the form we absorb from vitamin A rich animal foods. The liver can then convert retinol into the other 2 forms. Beta-carotene is a carotenoid in orange and yellow pigment. - EX: cooked carrots, squash, kale, spinach, red peppers, apricots, cantaloupe. It's important to keep in mind that cooking has more retinol activity. Cooking helps break down the rigid plant cell wall and liberate the beta carotene. Thus, raw isn't always better. - Beta-carotene is a lipid soluble. Its bioavailability increases if sauteed in butter or oil. - Just like protein, vitamin A is also a jack of all trades BENEFITS:  - Cell differentiation: cells divide then differentiate, they form an identity. Vitamin A is required for differentiation. Cells divide and then form an identity. All body surfaces are covered by layers of epithelial cells. These cells line the inside of the body are the mucous membranes. Without vitamin A, the normal structure and function of the cells in the mucous membrane are impaired. - Vision: - Antioxidant function: beta-carotene and other carotenoids work as powerful antioxidants. DEFICIENCY: - Increase rates of infection - Keratinization of the skin - Permanent blindness. 2. Vitamin D: - Sunlight + cholesterol + body heat = vitamin D - Anything that blocks UV radiation prevents us from synthesizing vitamin D including: sunscreen, clothing, air pollution, tall buildings - The AI for vitamin D is 600 IU. - The intestine absorbs only 10% to 15% of the calcium in foods. Cells cannot deposit enough calcium to produce strong bone tissue. BENEFITS: - Bone development: when skin cells are exposed to the sun, the radiation converts a substance into an inactive form of vitamin D3. Once in your bloodstream, it finds its way to your liver and kidneys. When calcium is needed, the kidneys convert calcidiol into vitamin D. - Regulate cell growth - Cancer fighting properties DEFICIENCY: - Rickets: deficiency disease in children characterized by bowed legs. In adults, this is called osteomalacia and can lead to osteoporosis. Too much vitamin D = too much calcium. Calcium deposit in soft tissues of the body, including arteries and kidneys can cause damage. 3. Vitamin E: - Vitamin E is the major fat soluble antioxidant found in cells. Vitamin E carries extra electrons. Without vitamin E, red blood cells can open and spill their content.  - Vitamin E protects PUFAS in cell membranes from being damaged by radicals. Free radicals also oxidize LDL deposited in plaque. 4. Vitamin K: - Important for the synthesis of blood clotting factors - Vitamin K is synthesized by the bacteria living in the large intestine. - Is supplied by the diet. DEFICIENCY: - Infants are at risk for vitamin K deficiency bleeding (VKDB). Lesson 7.4: Water Soluble Vitamins: 1. Vitamin B: - Vitamin B is crucial for energy metabolism. Along with some minerals, vitamin B supports the generation of energy from the macronutrients. Without vitamin B, your body can be lacking energy. (help convert food into energy) - B vitamins work with coenzymes, they bind together. Coenzymes are small molecules that activate the enzymes. Without the binding, the enzyme remains inactive, it cannot catalyze a chemical reaction. a) Thiamin (B1): - Prison, chicken and rice are all connected to thiamin. Starting with rice, it's a grain that has 3 parts. Removing the bran and embryo, you are left with starch. Disregarding bran is rich in thiamin. Eating just rice is linked to beriberi disease. Chicken that fed on leftovers from prisoners' plates developed beriberi-like symptoms. - Beriberi symptoms: weakness, memory loss, weight loss - Wernicke Korsakoff: deadly thiamin deficiency that develops in alcoholics, leaving permanent brain damage. b) Riboflavin (B2): - Deficiency associated with riboflavin is rare. However, when it does occur it includes weakness, inflamed tongue and sores on the edge of the lips. Exposure to light causes the vitamin to break down rapidly. Milk (rich in riboflavin) is stored in cardboard or opaque containers. 30 minutes of UV light will destroy 30% of vitamin B2.  c) Niacin (B3): - Part of 2 coenzymes that participate in many reactions. We can produce small amounts of niacin using one of the amino acids. The rest of the niacin must be supplied by the diet. - The absence of niacin is a deficiency disease called Pellagra. The 3 D’s of pellagra are: dermatitis, dementia and diarrhea. Back then, pellagra was considered another infectious disease affecting the poor. Mostly found in corn, however, in Mexico, corn kernels are soaked in lime to help free the niacin from the protein making them immune to pellagra. d) Vitamin B6: - Very important!!! A coenzyme for over 100 enzymes. Unlike most B vitamins, megadoses of vitamin B6 are toxic. B6 are crucial for energy metabolism, amino acid metabolism and heme synthesis. - 11 of the 20 amino acids are non essential, meaning they can be synthesized by the cells of the body. Catch is vitamin B6 is necessary for making the non-essential amino acids. Without it, all amino acids are essential. Conversion of the amino acid tryptophan to niacin requires vitamin B6. - Homocysteine: vitamin B6, B12 and folate are necessary in keeping levels of homocysteine low. This is TOXIC. To keep these levels low, B6 converts it quickly to cysteine. If the body lacks vitamin B6, homocysteine can accumulate in blood causing CVD. because anything that causes irritation to blood vessels leading to inflammation increases the risk of developing CVD. Heme synthesis: - Hemoglobin consists of 4 polypeptides. Each heme is essential to iron, which binds to the oxygen you inhale. Hemoglobin that carries the oxygen to your cells. Without Vitamin B6, anemia develops. Without oxygen, your cells cannot break down macronutrients to obtain energy. Oxygen deprived cells die. Folate: - Folate has 3 key roles: energy metabolism, amino acid metabolism and DNA metabolism. - Folate deficiency affects cells that divide rapidly. Rampant DNA synthesis happens during embryonic development. The neural tube develops into the brain and spinal cord. Deficiency disease is called: Spina Bifida: where the tube fails to close properly. Anencephaly: brain is malformed or missing. They usually die shortly after birth. Your risk increases if you are carrying twins. → Canada has mandated that all wheat flowers are fortified with folic acid. In the 4 years following fortification, neural tube defects fell by 46%.  e) Vitamin B12: - Required for energy metabolism, DNA metabolism, amino acid metabolism and maintaining myelin sheaths. Without vitamin B12, segments of the myelin sheath gradually undergo destruction that can lead to neuropathy which is the degeneration of the spinal cord. Vitamin B12 and absorption: - HCI and pepsin release B12 from the protein. Once the vitamin is released from the protein, intrusif factor (IF) binds to it. When the vitamin B12 reaches the ileum vitamins are absorbed. - Pernicious anemia is the result of the protein not being produced, or having the wrong shape because of incorrectly placed amino acids. - Many people over 50 years of age are vitamin B12 deficient. TREATMENT: - Monthly injections of vitamin B12 - Nasal gels/sprays containing vitamin B12. - Dietary supplements 2. Vitamin C: - Scurvy: best known deficiency disease (eating oranges, citrus is the best to avoid this) - Vitamin C is crucial for synthesis of collagen. Without it, collagen has somewhat the consistency of gelatin. - Vitamin C is best known for its antioxidant power. It's the water soluble antioxidant. - Smokers are encouraged to increase vitamin C intake to repair damage to their lung tissues. Lesson 7.5: QUIZ Lesson 8: MINERALS READINGS: what is food: chapter 8 + nutrition for healthy living: chapter 9 Introduction: defining features of minerals, major minerals and their functions, deficiency disease & trace minerals. Lesson 8.2: Defining Features of Minerals: - Minerals are indestructible. They come from the earth, we cannot create them from the earth. No living organism synthesizes minerals. - In the human diet, we require 7 major elements: sodium, magnesium, potassium, calcium, phosphorus, sulfur and chlorine. 8 trace minerals: chromium, manganese, iron, copper, zinc, fluoride, selenium and iodine. 25% of the elements found on earth are required by the human body. Major minerals are required for about over 100 mg/day and trace minerals less than 100 mg/day. However, not because it's required less that it's less abundant. Iron (Fe) is the most abundant trace mineral. Compartmental Body Fluids: - Intracellular fluid: inside cells - Extracellular fluids: interstitial fluid or inside the blood vessels is the intravascular fluid. Sources of Minerals: 1. Water: - “Hard” water: high concentration of calcium and magnesium (the greater the mineral content, the harder the water) - “Soft” water: treated with sodium or potassium. 2. Dietary supplements: - Minerals have a narrow range of a safe intake, it's easy to consume a toxic amount. Lesson 8.3: Major Minerals: 1. Calcium: - 99% of calcium is found in bone and teeth. Calcium is stored in bones as hydroxyapatite crystals. Calcium in bones also acts as a reservoir for when blood calcium levels drop. - 1% is found in intravascular and interstitial components as Ca++ in ionic form. Electrical signals open protein channels for calcium to flood into the presynaptic neuron. Without calcium, the neurotransmitters are not released and neurons fail to communicate. Blood calcium must be tightly controlled. - Osteoclasts cells: degrade bone tissue, osteoblasts cells: build bone tissue. When blood calcium levels drop, bone is demineralized to liberate calcium into the blood. As we age, the activity of osteoblast cells declines but osteoclasts cells continue to function leading to bone loss. The activity of these are regulated by the thyroid and parathyroid gland. - Calcium and peak bone mass: peak bone mass is defined as the highest attainable bone density achieved in the first 3 decades of an individual's life. This is somewhere in your 20s, regardless of gender. After 30 y/o bone density goes down, especially during menopause due to estrogen. Falling blood calcium levels: Step 1: PTH (parathyroid hormone) stimulates activation of vitamin D in kidneys Step 2: PTH vitamin D duo increase calcium reabsorption in kidneys Step 3: vitamin D travels to the small intestine and increases bioavailability of calcium. Step 4: PTH vitamin D duo stimulate osteoclasts to break down bone. Signal osteoclasts release calcium from bones. DEFICIENCY: - leads to osteoporosis: a disease of severely low density. Cause weak bones and susceptible to fractures. Shrinking in height is a tell-tale sign of osteoporosis and is caused by the collapse of the vertebrae. To minimize this, maximize peak bone mass, resistance exercise well into older age and meet the RDA for calcium. 2. Phosphorus: - 85% stores in bones, stores as hydroxyapatite crystals. 15% is found in the intracellular fluid compartment. - Phosphorus is in everything we eat, nearly impossible to be deficient in it. It is found on soft drinks. Consuming little calcium and too much phosphorus can cause calcium to leach out of the teeth causing severe tooth decay. 3. Magnesium: - More than half of the body's magnesium is found in bones. It influences the formation of hydroxyapatite crystals. It is found inside the cells. 27% of magnesium is found in muscle cells and 7% in other body cells.  - Magnesium in plants is found associated with chlorophyll. Any deep green leafy vegetable is a good source of magnesium. If intake is low, your body will take it from your bones. 4. Sodium: - “Table salt” or simply “salt” is sodium chloride –a compound comprised of sodium and chloride. Once mixed in water, salt dissociates into ions. Both sodium and chloride are found in the extracellular fluid compartments. - Sodium is crucial in fluid balance and nerve impulse transmission. - Chloride also plays a role in fluid balance, but more importantly, it becomes part of the - hydrochloric acid in the stomach. - The acid that forms in your stomach has its origins in salt! - We mine salt from deposits made by ancient seas. This is the source of your standard - inexpensive table salt. - But fleur de sel is made from the evaporation of small artificial salt ponds. As the water - evaporates, the salt is scooped up by hand. This is why you pay 10 times the regular - price of mined salt. Neural Communication Most sodium in the body is found in the intravascular and interstitial compartments. Sodium is crucial in nerve impulse transmission. Similar to calcium, sodium is critical in propagating the electrical impulse down the body of a neuron. 7 Recall that as the electrical signal travels down the presynaptic neuron, tiny channels open up and calcium floods into the neuron. Once inside, it allows neurotransmitters to spill into the synaptic cleft. This is where sodium comes into play. Neurotransmitters bind to the tiny channels embedded in the membrane of the post-synaptic cell. These protein channels open up, and sodium floods into the neuron. This influx of sodium allows the nerve impulse to be propagated. In short, an electrical stimulus opens calcium channels and a chemical stimulus opens sodium channels. Without calcium or sodium in the extracellular compartments, neural communication breaks down. 13. Fluid Balance Sodium is also crucial for maintaining fluid balance and crucial in controlling the volume of the extracellular fluid compartment. In general, the more sodium you consume, the larger the volume of the extracellular fluid compartment. As you will learn in lesson 9, where ions go - water follows. The enlarged volume of the extracellular fluid compartment places more pressure on arteries. With time, these arteries stiffen. High sodium intake is associated with hypertension — a state of chronically elevated blood pressure. Persistently high blood pressure places greater stress on the heart to pump blood through the stiff arteries. Note the thickness of the muscle tissue of the enlarged heart. Similar to enlarged biceps from lifting weights, a heart gets big from working hard to pump blood through stiffened arteries. But an enlarged heart is not desirable and can lead to heart failure. Children are increasingly affected by hypertension. How is this possible? Simple. Most people exceed the UL for sodium by several hundred milligrams every day. 14. Sodium – Tolerable Upper Intake Level (UL) The Tolerable Upper Intake Level (UL) for sodium for adults is 2,300 mg per day. The adequate intake (AI) is 1,500 mg per day. Most Canadians and Americans consume 3,400 mg per day! Approximately 4.5 million adults in Canada suffer from hypertension. Treatment to reduce hypertension involves lowering sodium intake. 8 Most of the sodium we consume doesn't come from the salt shaker at home. The majority—75 to 80%—is added during food processing and at restaurants, either as salt or sodium-containing food additives. This is why both Canadian and the US health professionals are working to determine ways of reducing sodium intake at the population level. In Canada, in 2010, the Sodium Working Group released The Sodium Reduction Strategy for Canada. The report concluded that a reduction of 1,800 mg of sodium per day would decrease CVD by 13%. This works out to 23,500 fewer premature deaths per year. 15. Potassium (K) 95% of the body's potassium is found inside cells, along with magnesium, but in much greater amounts. It is found in a large variety of real food. Since potassium is found inside of cells, processed foods have lost their potassium because cells are no longer intact. The potassium literally spills out and is lost. So if you eat real food…like a real apple, a real banana, a real potato, then potassium intake is probably close, even exceeds the AI. Otherwise it is not! Unlike sodium, potassium is associated with lower, rather than higher, blood pressure values. A natural way to counteract high sodium intake is to consume foods naturally rich in potassium and low in sodium, such as fruits. We will come back to this in the next lesson. TRACE MINERALS: 1. Trace Minerals And now for the trace minerals. With the exception of iron and iodine, the rest of the trace minerals have only been recognized as essential to humans within the last 60 years. The most abundant trace mineral in the body is iron. 2. Iron (Fe) Over 60% of iron is found inside red blood cells. Every day we produce 2 billion new red blood cells. Each one contains 280 million hemoglobin molecules. Each hemoglobin is studded with 4 heme compounds that bind to iron and iron binds to the oxygen that we inhale. As we inhale and fill our lungs with oxygen, the oxygen crosses through the epithelial cells of the lungs and enters the blood capillaries. Oxygen enters inside the red blood cells and binds to the iron. Without iron, oxygen has nowhere to bind. Thus too little iron is deadly. But too much iron is just as deadly. Ingestion of iron containing supplements is the leading cause of accidental poisoning in young children. 3. Absorption of Iron The body needs to tightly control the bioavailability of iron. The epithelial cells of the small intestine produce ferritin [fer-ah-tin], a key iron-binding protein. Ferritin binds and stores iron, thereby preventing it from escaping from the epithelial cells and entering the bloodstream. Ferritin is shown in this image as the tiny blue square. © 2 © May not be copied or duplicated without the permission of the owner. Notice how they bind to iron, represented as ruby colored beads. Iron bound to ferritin is unavailable for absorption. For someone with a healthy iron status, the amount of ferritin produced is in proportion to the body’s iron levels. When iron levels are very low, like during a state of iron deficiency, low amounts of ferritin are synthesized. The absence of ferritin allows iron to be absorbed into the epithelial cells and exit from the other end, and enter into blood capillaries. During a state of iron abundance, larger amounts of ferritin are made that bind to iron inside the epithelial cells, preventing it from entering blood capillaries. Given that the lifespan of an epithelial cell is about 3 days, most of these iron-rich cells are sloughed off and away goes the iron, excreted in feces. Depending on the iron status of your body, absorption can vary between 5% and 40%. 4. Bioavailability of Iron Thus the bioavailability of iron greatly depends on our body’s physiological need for it. But iron bioavailability also depends on the source of iron. The animal flesh that we eat was at one time richly supplied with blood. This blood contains RBCs packed with hemoglobin. This is the source of heme-iron. Heme-iron gets its name from the heme it is attached to. Plants do not have blood, but they do have iron. This is non-heme iron. But plants, as we’ve seen a few times already, contain binding compounds that reduce the bioavailability of some nutrients, including non-heme iron. Despite the lower bioavailability of non-heme iron, it accounts for 90% of the daily intake of iron. 5. Iron-Deficient Anemia Worldwide iron deficiency is the most common nutrient deficiency. It is also ranked high among preventable deficiency diseases. Iron-deficient anemia refers to severe depletion of iron stores that results in a low hemoglobin concentration. Consequently, red blood cells are smaller and paler in color. Because oxygen transport in blood is impaired, a person suffering from iron-deficient anemia has to work harder to circulate oxygen-poor blood throughout the body. Once again, as with hypertension, the heart is overworked. Over time, the heart enlarges, and eventually leads to heart failure. 3 © May not be copied or duplicated without the permission of the owner. High risk groups for iron deficiency include women in their reproductive years – due to monthly blood loss, pregnant women – due to increased blood volume, infants, young children, and teenagers because of rapid growth. Did you know that donating half a litre of blood represents a loss of 2.5 mg of iron? It takes the body several months to replace the iron that was in the donated blood. 6. Iodide Upon absorption, almost all iodide ends up in the thyroid. Iodide has a singular function – the synthesis of thyroid hormones. The role of thyroid hormones is to regulate body temperature and the body’s metabolism. This is why problems with the thyroid gland are often accompanied with weight loss or weight gain. 7. Iodide Deficiency Diseases The ocean is the world’s major source of iodide. Iodide is found in rich supply in soils that were once submerged by ancient seas. Remote populations, living far from any ocean, have iodide-deficient soils. Iodide- deficient soils make for iodide-free plants. Animals eating iodide-deficient plants are themselves iodide deficient. Goiter is a condition caused by a deficiency in iodide and results in an enlarged thyroid gland. The gland enlarges in hopes of capturing more iodide from the blood. But the iodide is simply not there. Cretinism [kree-tin-ism] is the most damaging consequence of a lack of iodide. Cretinism affects the developing fetus of pregnant women who are deficient in iodide. The severely impaired metabolism of the developing fetus causes severely impaired development. Both physical and mental development is stunted. Iodide deficiency is the leading cause of mental impairment globally. Iodine has been added to table salt since the 1920s to prevent iodine deficiency diseases. Furthermore, a program to eliminate iodine deficiency diseases has been adopted by United Nations. Despite efforts, still about 2 billion people worldwide suffer from iodide deficiency. The fleur de sel we saw earlier does not contain iodide. Surprisingly, some 29% of the Canadian population have mild iodide deficiency. Perhaps the increased popularity of gourmet salt is partly responsible. 4 © May not be copied or duplicated without the permission of the owner. 8. Chromium Recall that insulin is the hormone that allows glucose to enter into cells. Chromium enhances the ability of insulin to take glucose into your cells. Included here is an ad from the Jamieson supplement company. The claim for chromium is partly true. Chromium does help with glucose metabolism, but then the truth is stretched. Chromium is supposed to build muscle and burn fat. The words "supposed to" should be a red flag. Supplement advertisements often push chromium beyond the limits of what we know it can do. The statement necessarily ends with “but this has not yet been proven”. 9. Zinc Zinc does it all. Zinc is required as a cofactor by more than 100 enzymes. Enzymes that bind to minerals are called metalloenzymes. The minerals are called cofactors. Similar to when we referred to B-vitamins as coenzymes. Zinc is truly a versatile mineral. It is required for everything from energy metabolism to growth and development. 10. Zinc Deficiency A deficiency in zinc severely impairs growth and development. The image shown here shows how severely growth can be stunted. Both these men are the same age. The one on the left was —during childhood —zinc deficient. The popularity of zinc lozenges is attributed to its role in immune function. It seems that some research has shown that zinc lozenges can reduce symptoms of a cold by a few days and a deficiency in zinc increases risk of infection. 11. Zinc, Copper and Selenium Zinc, copper, and selenium all play a role as antioxidants. The special mention goes to selenium. Selenium works as a powerful antioxidant. Research indicates that adequate selenium intake can protect against some forms of cancer. But like iodine, your intake can depend on your geographic location. 5 © May not be copied or duplicated without the permission of the owner. Soils is Brazil are among the richest in selenium on the planet. If you want to increase your selenium intake, a few Brazil nuts a day will do the trick. 12. Fluoride Our last trace mineral is fluoride. Fluoride gets deposited in hydroxyapatite crystals in teeth to form fluorapatite [flo-rah-pa-tite]. This makes teeth far more resistant to decay. Close to 60% of children have one or more dental caries. Fluoridated water decreases rates of tooth decay by promoting the formation of fluorapatite. In Canada, fluoridated water varies between regions. This can lead to more or fewer cavities depending on the presence of fluoride in your water supply. Of course, as with any mineral, too much fluoride is toxic. One symptom of fluoride toxicity is the mottling of teeth called fluorosis [flo-roh-sis]. LESSON 9: Lesson 9.2 Transcript: Osmosis 1. Water is a Major Component of Body Cells An adult body contains approximately 40 liters of water. About 2/3rds of that water is found inside of cells. Some cells, like muscle cells and epithelial cells, contain 70 to 80% water. While others, like fat cells and bone cells, contain less than 20% water. 2. Extracellular Fluid Compartment The rest of the 40 liters, approximately 1/3rd, is contained within the extracellular fluid compartment. We’ve mentioned already that the extracellular fluid compartment includes the intravascular compartment – shown here as the cardiovascular system, the lymphatic system, and the interstitial fluid compartment. The extracellular fluid compartment also includes sweat, tears, gastric juices, spinal fluid, and fluid between joints. To function properly, the body must maintain the correct amount of water in each type of cell and compartment. How is this possible? The ability of water to move freely and accurately between compartments is crucial. In lesson 3, we stated two golden rules in chemistry. Here is a third. Where ions go, water follows. More elaborately, water molecules move toward compartments with the highest concentration of solutes. By controlling the amount of solutes within each compartment, the body can control the amount of water inside and outside of cells. 3. The Power of Solutes To understand the power of solutes, cut open an eggplant. Place some salt over it then wait a few minutes. Within a short time, water leaves the plant cells and pools to the surface, where salt is most concentrated. © 2 © May not be copied or duplicated without the permission of the owner. Conversely, raisins placed in water quickly begin to swell as water moves inside where sugar is most concentrated. This simple chemistry rule known as osmosis is crucial for understanding fluid balance. It is also crucial in cooking. Salting meat well before you cook it, draws out water from the muscle cells preventing you from properly searing the meat. 4. Osmosis Osmosis is defined as the diffusion of water through a selectively permeable membrane. In this example, a selectively permeable membrane separates two halves of a beaker. In the body, this “selectively permeable membrane” is the membrane of your cells. The membrane is porous to water molecules only. Solutes may not cross freely. In the first panel, the solute concentration is equal on both sides of the membrane. Free-moving water molecules cross from one side of the membrane to the other. Other water molecules are not so free. They are hydrogen bonded to the solutes. Given that both sides have an equal concentration of solutes, we have an equal concentration of free and not-so-free water molecules. In the second panel, side B receives additional solutes thereby raising the solute concentration. As the unsuspecting free water molecules cross over to the B side, they become hydrogen bonded to the solutes. Soon, side B contains more hydrogen-bonded water molecules and the volume of water increases. Thus, the body maintains the balance of compartmental fluids by controlling concentrations of ions in each compartment. To control the movement of water, the cells direct the movement of major minerals. Most notably: sodium, potassium, and magnesium. Although chloride, phosphorus, and sulphur also play a role. These minerals, called salts, dissociate when placed in water into ions with either positive or negative charges. Water molecules are immediately drawn to them. These charged ions are called electrolytes. For example, table salt placed in water dissociates into sodium and chloride. Cations are positively charged ions, while anions are the negatively charged ions. 1. The Roles Water Plays in the Body Now that you understand how water moves between compartments, we can look at some of the roles water plays in the body. The most important function is the transport of nutrients and waste. Recall that blood is made up of red and white blood cells and plasma. Plasma is mostly water with suspended nutrients that are delivered to your cells and waste that is delivered to the kidneys for elimination. Urine itself is mostly water with suspended body waste. Water also participates in chemical reactions. In fact, some of the water in our cells is the product of chemical reactions. This is called metabolic water. The amount of metabolic water produced per day depends on your physical activity level: physically inactive people produce about 300 mL of water per day, while very active people produce about 550 mL of water daily. 2. Water Regulates Body Temperature Water also regulates body temperature. During exercise, blood rushes to the surface of the skin carrying the heat generated from the metabolic reactions in your cells. The blood capillaries near the surface of the skin dilate, allowing more blood to flow through them. This is why you turn red when exercising. This increase in blood flow allows more heat to dissipate thus cooling down your core. The heat can escape by crossing through the skin and through the sweat glands. Sweat is what allows the body to cool during exercise. But this only works if the sweat is allowed to evaporate. How so? Sweat evaporates similarly to how trees pull water from the roots against gravity all the way up to the leaves. Water that reaches the leaves comes into contact with the surrounding air. © 2 © May not be copied or duplicated without the permission of the owner. At the air-water interface, water molecules evaporate. As they evaporate, the column of water molecules that stretches all the way down to the roots is pulled up. If the air is saturated with water molecules, as it would be during a very humid day, water does not evaporate, and the column of water does not get pulled up. The same thing happens at the air-water interface of your sweat glands. For warmed interstitial water to be continuously pulled up to the surface of the skin, water molecules need to evaporate. If the air is too humid, the heated body water remains trapped in the body. Consequently, heatstroke can occur. So you can think of your sweat glands as tiny little bonsai trees that move heated interstitial fluid out of the body. Lesson 9.4 Transcript: The Roles of the Kidneys A human body is composed of 50 to 70% water. The percentage of water in the body varies by at least 2 factors. The first is age. A newborn contains about 75% water by weight while an elderly person is 45% water by weight. The second is sex because body composition matters. Recall that muscle tissue contains more water than fat tissue. Given that, on average, young adult men have more lean tissue than young women. It follows then, that men have more body water than women. 1. Daily Water Intake/Production and Losses Regardless of age or sex, the body maintains a near constant amount of water. Water sources include water from beverages and food. Fruits and vegetables can contain up to 90% water while cheeses up to 50% water. Metabolic water is also a source of water and it is produced from the chemical breakdown of macronutrients. Intake is balanced with water losses. The kidneys eliminate water, along with waste, in the form of urine. The rest of the losses occur through the skin in the form of sweat, through expired air, and through feces. The kidneys and the brain work cooperatively to maintain the right amount of body fluid. Every time the heart contracts, 21% of the blood that is forced out heads directly to the kidneys for processing. 2. Eliminating Waste Each minute the kidneys receive nearly 5 cups of blood. Pause for one minute and imagine these 5 cups of blood reaching your kidneys for processing. From this, they will make about 1 mL of urine per minute. The kidneys receive blood from the heart via the renal artery. Waste is removed from the blood and the cleaned blood leaves the kidneys via the renal vein. The waste, along with water, reaches the bladder via the ureter. © 2 © May not be copied or duplicated without the permission of the owner. 3. Controlling Blood Pressure In addition to eliminating waste, the kidneys also control blood volume, blood pressure, and the solute concentration of body fluids. After all, blood plasma is about 92% water. The volume of this fluid compartment influences blood pressure. The greater the amount of fluid, the greater the amount of pressure on the walls of the blood vessels. Conversely, low blood volume leads to low blood pressure. The kidneys themselves are controlled by secretions from the posterior pituitary gland located in the brain and the adrenal glands that sit on top of the kidneys. The pituitary gland secretes antidiuretic hormone, ADH, and the adrenal glands secrete aldosterone [ehl-DAW-steh-rone]. These two hormones control the volume of urine and its solute concentration. Before learning more about kidney function, make a mental note of our third golden chemistry rule: water always follows ions. The posterior pituitary gland releases antidiuretic hormone when blood volume is low, or when the concentration of sodium in blood plasma is high. In both cases, water must be conserved either to increase blood pressure or to dilute the concentrated extracellular solution. In fewer words, ADH makes less urine. Working alongside the pituitary gland, the adrenal glands secrete aldosterone. Aldosterone signals the kidneys to reduce the elimination of sodium in urine. And because water always follows ions, water is conserved as well. Furthermore, both ADH and aldosterone promote the elimination of potassium – an intracellular ion. By doing so, they encourage water to remain in the extracellular compartment and not migrate into body cells. 4. Managing Blood Pressure Now that you understand kidney function and the third golden chemistry rule, you should be able to make your own sound dietary recommendations for reducing high blood pressure. One way to lower blood pressure is to increase potassium and magnesium intake while reducing sodium intake. Cells that are more richly populated with electrolytes have the capacity to lower blood volume by drawing water out of the extracellular fluid compartments and into the intracellular compartment. 3 © May not be copied or duplicated without the permission of the owner. This approach to managing blood pressure is called the DASH diet – or Dietary Approaches to Stop Hypertension. In fact, even if you do nothing to reduce salt intake but increase potassium and magnesium, blood pressure can be significantly reduced. That is the power of osmosis Lesson 9.7 Transcript: What is ATP? Let’s delve deeper. Breathing saturates red blood cells with oxygen. Eating saturates your blood with nutrients. Blood capillaries is where gases, nutrients, and waste are exchanged between cells and the blood. Offloaded into the interstitial space, oxygen and biological fuels enter the intracellular space and flow into the mitochondrion – the ATP factory of every cell. The end product of this catabolic chemical reaction is metabolic water, carbon dioxide, and ATP. Carbon dioxide is moved into the blood capillaries and exhaled from your nose. Water is used by the cell, and ATP is a highly reactive molecule ready to perform work. The number of mitochondria per cell varies as a function of their metabolic rate. Energy demanding muscle cells are saturated with mitochondria as are the cells of the liver. Less metabolically active cells like fat cells have fewer mitochondria. ATP contains about 40% of the chemical energy that was stored in the carbon-hydrogen bonds of glucose. The rest was lost as heat. But why is ATP the energy currency of the cell? And how does it work? After all, ATP is merely a compound like millions of others. What makes it different? For starters, it is highly reactive because of the cluster of negatively charged oxygen atoms in close proximity. This makes ATP analogous to a compressed spring. To carry the analogy further, a compressed spring is an object just like a table is an object. But a table can’t perform work. A spring can. Highly unstable, the last phosphate group of ATP is released and the energy is liberated in the form of kinetic energy. Imagine if you were standing in front of a larger than life ATP molecule. As the last phosphate is released, it transfers its stored energy onto you and causes you to jerk. You’ve been phosphorylated. If you were continuously phosphorylated, you would be dancing! In reality, motion is caused by the contraction of muscle fibers that move the skeleton. At the cellular level, muscle fibers get phosphorylated allowing them to slide past each other and contract. © 2 © May not be copied or duplicated without the permission of the owner. Enzymes and other protein get phosphorylated causing them to change configuration and perform work. The result of losing the last phosphate turns ATP into ADP. Here is an example of how the sodium-potassium protein pump is put to work. ATP phosphorylates the transmembrane protein, causing it to continuously change shape. As it changes shape, sodium is pumped out of cells while potassium is pumped inside. The protein is in constant motion because it is continuously phosphorylated. Consequently, ATP must be in constant supply for the sodium-potassium protein pump to work and for you to maintain fluid balance. ATP is synthesized from adenosine diphosphate (ADP) and a phosphate. The energy for the reaction is supplied by the breakdown of macronutrients. By eating energy-rich meals, we provide the mitochondria with the fuel necessary to make ATP. ATP is then used for the day-to-day business of the cells of the body. If we take the liver as an example, the day-to-day business includes many vital functions. By starving yourself during crash diets, the liver, among other organs, pays the price. Lesson 9.8 Transcript: Energy Input and Output Energy input comes from carbohydrates, lipids, and protein. If we base it on the AMDRs, the bulk should come from carbohydrates, followed by lipids, then protein. Energy in must equal energy out for individuals wanting to maintain a stable weight. The outlet includes the energy used for physical activity, the energy used to digest and absorb food, and the energy used to run your basic metabolic needs. The lion’s share is taken up by your basal metabolism. 1. Basal Metabolism Basal metabolism is the energy spent to maintain life when the body is completely at rest. That means you are not digesting food, running, emotionally distressed, or studying. Let’s call it housekeeping. A body’s basal metabolic rate, or BMR, is the rate at which this energy is spent for housekeeping. You can vacuum fast or slow, but you must vacuum. The BMR is measured after fasting and resting for 12 hours. It calculates the energy spent for breathing, circulating blood and maintaining organ functions. It does not include the energy spent for physical activity, digestion of food, and absorption and processing of nutrients. BMR is measured in kilocalories per kg of body weight per hour. 2. BMR Shown here is the average number of kilocalories consumed per day per organ. The liver, as we already mentioned, takes the biggest share, followed closely by the brain. This is why an adequate diet is important for getting straight As in school. From this example, basal metabolism accounts for 1,400 kilocalories per day. This means that if you consume an average of 2,000kcal/day you need to spend close to 600 kilocalories in physical activity to maintain a stable weight. The more calories you consume the more you need to spend on physical activity. © 2 © May not be copied or duplicated without the permission of the owner. But why is BMR measured only after 12 hours of fasting? To answer this question, let’s return to lesson 4 on carbohydrates. Make a mental list of all the enzymes that are necessary for carbohydrate digestion. How about lesson 5? Which enzymes are needed for lipid digestion? What about protein? 3. Energy Input and Output But mechanical digestion is also costly. That ripple of peristaltic contractions along the alimentary canal to keep food moving requires an input of energy for the muscles to contract. The muscles are being constantly phosphorylated by ATP. Furthermore, the stomach churns the food for extended periods of time to break up the chyme before it enters the small intestine. This is why you are tired after a big meal. 4. Thermic Effect of Food (TEF) The thermic effect of food is therefore the estimated amount of energy required to process food. It consumes about 10% of your total caloric intake. Processing includes digestion, absorption, transportation, and metabolizing the nutrients. For example, once absorbed, fructose is delivered to the liver and converted to glucose which is then used to make glycogen. All this work requires an input of ATP. 5. Energy Input and Output Everyone knows that physical activity consumes energy. If your total caloric intake is 2,000 kilocalories, your weight will be controlled by how much of those extra calories you spend. If you spend those extra calories through regular exercise, your weight remains stable. If you lead a sedentary life, the pounds will begin to accumulate because excess energy, whether it is in the form of carbohydrates, lipids, or protein, will get stored as fat in adipose tissue. Weight loss will occur when energy expenditure exceeds the intake. 3 © May not be copied or duplicated without the permission of the owner. Here is a list of the energy expended for various physical activities. In addition to calories, dollar bills are also spent for engaging in many of these activities. The least expensive is running. All you need is a pair of sneakers. Since that is really all that is needed, you can argue that splurging for a good pair is an excellent investment. What’s more is that running also helps the brain. The cognitive benefits include improved memory and by extension, improved grades. 6. Factor That Influence BMR Some people can eat a lot and not gain much weight, while others are far more sensitive. Several factors can affect and ultimately set your basal metabolic rate. These factors include: body composition, sex, body surface area, and age. Muscle tissue, being packed with mitochondria, is more metabolically active than fat tissue. Thus, the more muscle tissue you have relative to fat, the higher your BMR. And since men, on average, have higher muscle mass than women, your biological sex also influences BMR. Men have higher BMRs than women. Growing children also have high BMRs. This is why a teenager can eat an enormous quantity of food and not gain any weight. Meanwhile, old age slows down BMRs. 7. Factor That Can Influence Basal Metabolism How tall you are can also influence your BMR. Taller people have a greater total body surface area. Consider the stack of blocks shown here. Both structures contain 8 blocks, but the taller one has 34 exposed sides while the shorter one has only 24. A tall, slender person who weighs 150 lbs has a higher metabolic rate than a shorter person who also weighs 150 lbs. Why? Because the taller body has more surface area from which heat energy can escape. Consequently, to maintain body temperature, the taller individual has to burn more calories to replace the heat that is lost. But these are all, of course, averages. And averages are meant for a population and may not apply to the individual. An individual’s BMR can also be determined by the environment. ​Lesson 9.9 Transcript: Genes and Environmental Factors Your BMR is largely genetically determined, but genes do not control everything. The environment also plays a role. The environment can be experienced in utero, as a neonate, or during adulthood. 1. Role of the Environment on Development Now that we’ve convinced you that the environment can change you, let’s look at how fetal environments can potentially set the BMR. In a massive epidemiological study comprised of 16,000 men and women born in England between 1911 and 1945, low birth weight babies had a significantly higher risk of being obese as adults. The idea that caloric intake during pregnancy can affect BMRs has been studied for several decades. Known as the Thrifty Gene Theory, it is hypothesized that fetuses deprived of calories lowered their BMRs because they predicted an environment of food scarcity. But, as it turns out, the risk for obesity is far too complex to be able to point the finger at a singular cause like gestational caloric intake. 2. Quality of Diet Can Play a Role The quality of the diet can also play a role. In a study on the role of gestational nutrition on obesity, genetically similar mice carrying a gene mutation that increased the risk for obesity had very different fates because their mothers had very different diets. The mother of the mouse on the right received dietary supplements which silenced the obesity gene. In short, nutrients can, and do, affect gene expression. This is what we call epigenetics — the study of how the environment can alter gene expression. 3. Summary In lesson 1, we introduced nutrition’s sister discipline — nutritional genomics. The interaction between diet and genes goes two ways. Nutrigenomics studies how food can affect gene expression. © 2 © May not be copied or duplicated without the permission of the owner. Nutrigenetics examines how genetic differences influence how nutrients are metabolized. These interactions can, not only set your BMR, but also amplify or silence risks for other diet-related chronic diseases. What you eat can, and does, change you. We still have a long way to go before we can disentangle the role of the environment on gene expression. But given the overwhelming evidence of the interaction between genes and nutrition, the best one can do is learn how to cook simple, healthy meals to reduce risks of harm and increase chances of entering old age in the best possible Condition Lesson 9.5 Transcript: Water Deficiency & Toxicity Fluid and electrolyte imbalance can occur from water deficiency and toxicity. This sudden imbalance overwhelms the capacity of your kidneys to maintain fluid and electrolyte homeostasis. Deficiencies can be mild to severe. Vomiting and diarrhea can lead to excessive water losses in a short period of time. Simple water intake can treat this mild dehydration. For more severe cases, electrolytes must also be replenished. For example, during prolonged physical activity, extracellular electrolytes, along with water, are lost through sweat. If balance is not restored, this can lead to hyponatremia. The symptoms of hyponatremia include severe headaches, confusion, and seizures. What happens at the cellular level? Water leaves the intravascular and interstitial compartments and migrates into cells, including cells of the nervous system. Hyponatremia requires immediate medical attention. Sports drinks can ensure electrolyte balance during prolonged physical activities in hot temperatures. 1. Water Toxicity: There is No Upper Limit (UL) for Water, but… There is no Upper Limit for water. But, water intoxication can result from overconsuming plain water after prolonged physical activity. It can also be a consequence of taking drugs, like Ecstasy, that cause extreme thirst. Once again, the excess water dilutes the sodium concentration of blood and causes hyponatremia. Water moves into cells leading to symptoms that can escalate from headaches, confusion, seizures, and coma, to death. 1. Risk Risk is a measure of the probability that a substance, or activity, will cause harm under defined conditions of exposure. The key words here are “defined conditions of exposure.” The risk of dying from cancer in Canada is about 30%, closely followed by cardiovascular diseases. But these risks are at the population level. If you eat well, exercise, and don’t smoke, your risk can be substantially lower. Thus, risk is dependent on behavior. 2. The Relationship Between Risk and Behavior Let’s consider a more straightforward example of the relationship between risk and behavior. Bungee jumping. It seems that for every 500,000 people who bungee jump, one will meet their maker. The risk of dying is therefore 0.0002%. But what if you never bungee jump? Then, of course, your risk is zero. And if you are a bungee jump instructor? Well, you must multiply this risk by the number of times you jump. Is it 20 times per year? Then your risk jumps to 0.004%. Your risk of acquiring a foodborne illness obeys the same logic. If you never wash your fruits and vegetables and always undercook your meat, your risk increases. 3. Risk Each year in Canada, 4 million people get sick from domestically acquired foodborne illnesses. This translates to 1 in 8 people. The risk is 12.5%. For healthy people, the risk of dying from a foodborne illness is quite low. So why worry? We worry because a serious infection or repeated infections can wreak havoc on your guts and lead to chronic sequelae [sih-kweh-lee], or in other words, to chronic disease. © 2 © May not be copied or duplicated without the permission of the owner. As the author of a paper on chronic sequelae states: chronic sequelae may occur in 2 to 3% of foodborne disease cases. This gives us the necessary perspective from which we can begin this lesson. 1. Risk Risk is a measure of the probability that a substance, or activity, will cause harm under defined conditions of exposure. The key words here are “defined conditions of exposure.” The risk of dying from cancer in Canada is about 30%, closely followed by cardiovascular diseases. But these risks are at the population level. If you eat well, exercise, and don’t smoke, your risk can be substantially lower. Thus, risk is dependent on behavior. 2. The Relationship Between Risk and Behavior Let’s consider a more straightforward example of the relationship between risk and behavior. Bungee jumping. It seems that for every 500,000 people who bungee jump, one will meet their maker. The risk of dying is therefore 0.0002%. But what if you never bungee jump? Then, of course, your risk is zero. And if you are a bungee jump instructor? Well, you must multiply this risk by the number of times you jump. Is it 20 times per year? Then your risk jumps to 0.004%. Your risk of acquiring a foodborne illness obeys the same logic. If you never wash your fruits and vegetables and always undercook your meat, your risk increases. 3. Risk Each year in Canada, 4 million people get sick from domestically acquired foodborne illnesses. This translates to 1 in 8 people. The risk is 12.5%. For healthy people, the risk of dying from a foodborne illness is quite low. So why worry? We worry because a serious infection or repeated infections can wreak havoc on your guts and lead to chronic sequelae [sih-kweh-lee], or in other words, to chronic disease. © 2 © May not be copied or duplicated without the permission of the owner. As the author of a paper on chronic sequelae states: chronic sequelae may occur in 2 to 3% of foodborne disease cases. This gives us the necessary perspective from which we can begin this lesson.