Microbiology Nutrition Notes Year 3, Week 1 PDF

Microbiology Nutrition Notes Year 3 Week 1 Nutrition Matters How do we consume food? 1. Energy First law of thermodynamics: Energy can neither be created nor be destroyed, it can only be transferred fr...

Microbiology Nutrition Notes Year 3 Week 1 Nutrition Matters How do we consume food? 1. Energy First law of thermodynamics: Energy can neither be created nor be destroyed, it can only be transferred from one form to another. 2. Important nutrients that we can’t make ourselves For any organism, food is always a limiting factor Our bodies evolved ways to get the most out of the energy available AND developed preferences for food sources that would provide the best chance of survival Around 12,000 years ago the advent of agriculture changed the ways humans lived Humans went from hunter-gatherers to establishing permanent settlements with reliable food supplies from domesticated crops and animals With food supplies that could meet demand, the global population grew from ~5 million people just 10,000 years ago to more than 7 billion Metabolism For example, sugar stimulates dopamine in the reward centre of our brain and provides positive feedback For our hunter-gather ancestors, this was evolutionarily advantageous, since foods with lots of sugar, like fruit, provided energy and nutrients that offered a better chance of surviving But now, our diet contains many concentrated sources of sugar They trigger dopamine in our brains but provide much more energy, much faster than our bodies can use and often fewer nutrients “We have known since 1993 at least – when “Actual Causes of Death in the United States” was published in the Journal of the American Medical Association – that the leading causes of both premature death and persistent misery in our society are chronic diseases that are, in turn, attributable to the use of our feet (physical activity), forks (dietary pattern), and fingers (cigarette smoking).” What are the top 3 leading causes of death in Canada? - Stroke, heart disease & cancer Energy The unit for energy is measured in Kilocalorie, Kcal or Calorie One calorie (1/1000 of a Calorie) is the amount of heat it takes to raise one g of water one degree Celsius One calorie is equal to 4.18 joules One Kcal is typically enough energy to take ~25 steps Energy Providing Macronutrients - Carbohydrates - Lipids - Proteins 26 g Carbohydrates x 4 Kcal/g = 104 Kcal 0 g Lipids x 9 Kcal/g = 0 Kcal 2 g Protein x 4 Kcal/g = 8 Kcal 104 Kcal + 0 Kcal + 8 Kcal = 112 Kcal Macro = Large Fats/Lipids, Carbohydrates and Proteins and energy-producing macronutrients Water is a macronutrient that doesn’t produce energy Together they make up a large (macro) proportion of the human body Vitamins and Minerals are termed micronutrients (micro = small) because we need a small amount of them Micronutrients Micronutrients are important for cellular function. But are needed in small amounts. They can be: Essential: we cannot make them and must get them from our diet Non-essential: we can make them, but they are also available in our diet. Minerals - They must be gathered from our diet Vitamins - Can be essential or non-essential - Easily lost during processing Nutrients that are of special interest... - Saturated fats & trans fats - Fibre - Sugars - Cholesterol - Sodium The impact of alcohol Alcohol contributes 7 calories of energy per gram. A recent paper reported that hospitalizations in Ontario that were attributed to alcohol rose ~240% in women aged 25-29. In 2014, alcohol was attributed to $11.1 billion in healthcare costs Nutrition & Exercise Food provides energy, but we get much more from food than just energy. If we think about nutrition as only about energy, we risk falling into the trap that exercise is the “treatment” for poor nutrition. Exercise uses that energy, but we get much more from physical activity than just burning energy HAES® supports people in adopting health habits for the sake of health and well-being (rather than weight control). HAES encourages: Eating in a flexible manner that values pleasure and honours internal cues of hunger, satiety, and appetite. Finding the joy in moving one’s body and becoming more physically vital. Accepting and respecting the natural diversity of body sizes and shapes.  Week 2 Dietary Planning & Digestive Metabolism Some considerations when writing a food guide include: - Dietary needs in the population - Population health and well-being - Food accessibility and Supply chain Dietary reference intakes (DRIs): - DRIs are based on the nutritional needs of a population using statistics If we measure the nutrition need of a specific nutrient for a healthy individual and plot it on a graph, we will get a single point If we keep testing individuals in the population, we will get a spread of data ( aka normal data distribution) This type of data can provide important information such as: - Estimated average requirement or EAR, estimates the amount of a nutrient to meet the needs of 50% of the population - Recommended dietary allowance or RDA, based on EAR, but higher to encompass the needs of 97% of the population This data provides important information” - Estimated average requirement or EAR estimates the amount of a nutrient to meet the needs of 50% of the population - Recommended Dietary Allowance or RDA, based on EAR, but higher to encompass the needs of 97% of the population - Tolerable upper intake level or UL, the amount below which there is little chance of adverse health effect - Adequate intake or AI, value is used if there is insufficient data to calculate RDA Knowledge Check What is the risk in setting the recommended daily intake at the estimated average requirement (EAR)? 1) The recommendation will not meet the needs of 50% of the population 2) The recommendation would exceed the needs of 50% of the population What does it mean when a person is in a negative energy balance? 1) Using more energy than is being consumed 2) Consuming less energy than is being used 3) Consuming more energy than is being used 4) Using less energy than is being consumed Estimated Energy Requirements (EER) - Used to calculate calories to maintain a stable weight in healthy individuals Energy consumed - energy used = 0 (energy balance) - Based on age, gender, weight, height and activity level Acceptable macronutrient distribution ranges (AMDRs) - Recall the energy-producing macronutrients: carbohydrates, fat and proteins - Recommendations: Carbs 45-65%  Fat 20-35% Protein 10-35% What to consider when writing a food guide? - Health Canada created a report called the Evidence Review for Dietary Guidelines - These guides review scientific evidence and the Canadian context with respect to chronic diseases of concern - Cardiovascular disease, cancers, diabetes, and osteoporosis were some of the areas of concerns What food is accessible to the population? - There is no point in recommending a food that few people will have access to - Are there cultural preferences to take into consideration? For example: - Would you recommend a food that is extremely expensive to access in a northern Inuit community? - Would you recommend meat as a primary source of protein to a community that is a majority vegetarian? - Keep in mind for example in Canada we have many Metis, Inuit and First Nations peoples who do not have affordable choices in the territories and are lactose intolerant therefore their dietary pattern is not meeting their needs Association between foods and chronic diseases Convincing evidence - strengthened ↑ Vegetables and fruit: ↓ CVD and ↓ Cancer ↑ Dietary Fibre: ↓ CVD and ↓ Cancer Convincing evidence based on new findings ↑ glycemic index or load: ↑ Type 2 Diabetes ↑ Sugar-sweetened beverages: ↑ Dental caries in children Be mindful of your eating habits - How you eat - Why you eat - What you eat - When you eat  - Where you eat - How much you eat Cooking and preparing food can support healthy eating habits. Cooking allows you to: learn new skills rely less on highly processed foods control the number of sauces and seasonings make foods that you and your family like and will eat save money by avoiding extra money spent on meals eaten out choose healthy ingredients Enjoying your food includes: socializing at mealtime enjoying shopping for food preparing and cooking food growing or harvesting your own food getting to know the people that grow or produce your food involving others in meal planning, preparation and clean-up By eating with others you can: enjoy quality time together share food traditions across generations and cultures explore new healthy foods that you might not normally try What is the difference between a serving size and a portion size? - A portion is the amount of food that you choose to eat for a meal or snack. It can be big or small, you decide. - A serving is a measured amount of food or drink, such as one slice of bread or one cup (eight ounces) of milk.  - A serving size can be estimated by comparing to common objects… Adequacy Balance Calorie Control Nutrient Density Moderation Variety How can you assess nutritional health? Analysis of dietary intake - Food diaries or food intake records - Food frequency questionnaire - Diet history Anthropometric measurements - Heights, weight, BMI - Waist circumference - Weight change over time - Medical history and physical exam Laboratory measurements - Values of nutrients in blood - Markers of disease Case study Darra (She/Her) is a 23-year-old university student who came into the clinic reporting feeling tired and having difficulty concentrating in class. Medical history and physical exam Darra has lost some weight and recently started a vegetarian diet. What do you suspect may be the cause of Darra's symptoms? a)Stress from increasing classwork b)Low iron in her diet c)Not enough energy from her diet d)Not enough protein from her diet Canadian Community Health Survey CCHS began in 2000 Example: In 2015, 24.5% of youth, aged 12-17 reported being overweight or obese. That value increased to 27.2% in 2021. An increase of 130,000 people. One statistic examines Canadians’ nutritional status using a Healthy Behaviours Score (HBS) Calculated looking at 4 dimensions: Smoking status, Drinking habits, Physical activity level, Fruit and vegetable consumption Most recent data is from 2017 50.4% of Canadians aged 18 and older (roughly 13.4 million people) had an HBS of 3 or 4 Healthy Eating Food Index - The HEFI assesses how food choices align with Canada’s Food Guide 2019 - Strong adherence to the 2019 Canada’s Food Guide recommendations was associated with a 24% reduction in the risk of cardiovascular disease in middle-aged and older adults Everything starts with atoms Atoms form molecules which make up the proteins and lipids that form cells and tissues and the glucose that is used for energy For humans to grow and survive, we need a constant supply of new atoms and energy Since we can’t make atoms or create energy, we must get them other sources… Digestive, Absorption & Excretion The Gastrointestinal Tract consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus Digestion, Absorption and Excretion take place within the GI tract Transit time is the amount of time it takes food to pass the length of the GI tract Feces are waste, including unabsorbed food residue, bacteria and dead cells, that leave the body Digestion is the process of breaking down food sufficiently to be absorbed by the body Digestion mechanically (chewing, churning) and chemically (acids, enzymes) breaks down the food we eat into smaller and smaller pieces Absorption is the process by which useful molecules to enter the body Excretion is the process where any unabsorbed material, bacteria and dead cells leave the body Digestion Digestion begins as soon as food enters the mouth Chewing mechanically breaks down food into smaller pieces Saliva lubricates food and contains the enzyme amylase which starts to break down starch (carbohydrates) in the mouth In the stomach, gastric juice is released which contains: HCl (acidifying the stomach) Pepsinogen, inactive form of the enzyme pepsin Once activated by HCl, pepsin begins breaking down proteins In children, the enzyme rennin is released which helps digest milk Powerful stomach muscles churn the contents, aiding in digestion Chyme leaves the stomach in about 2-6 hours and enters the small intestine In the small intestine, digestion continues The pancreas releases;  Bicarbonate (neutralizes the acidic chyme) and Enzymes that further break down carbohydrates, protein and lipids The gall bladder releases bile salts Emulsify lipids, separating them it into smaller fat droplets which are more soluble and accessible to enzymes Absorption Most absorption occurs in the small intestine The small intestine is about 6 meters in length Villi and microvilli (protrusions from the stomach lining) increase the surface area of the small intestine Single sugars, amino acids and short chain fatty acids enter the portal vain and go the to liver Long chain fatty acids enter the lymphatic system and go directly to the blood stream Excretion Chyme moves through the small intestine in 3-5 hours Unabsorbed material enters the large intestine The large intestine contains a large bacterial population (gut microbiome) Gut bacteria break down unabsorbed food and can produce beneficial compounds for the body  Biological material will stay in the large intestine for ~24-36 hours before being excreted Immune function of the GI tract The GI tract acts as the barrier to the outside world, inside your body The immune system is interconnected within the GI Tract to prevent pathogens from entering body Phagocytes such as macrophages and lymphocytes such as B-cells and T-cells are present below the mucosa Food allergies occur when the immune system reacts to a protein in our food and triggers an immune response ~7% of Canadians have a food allergy Celiac disease is an example of a food allergy due to an immune response to the wheat protein gluten Commensal bacteria in the gut help fight pathogens by outcompeting them for nutrients Gut Microbiome The human gut contains an entire ecosystem of microorganisms Research is uncovering a link between types of bacteria in the gut and health Obesity, cancer, inflammation, cardiovascular disease, liver disease have all been linked with gut microbiota Studies are underway to manipulate the composition of gut microbiota to provide health benefits Lactose intolerance Lactase is an enzyme found in the small intestine that can break down the sugar molecule lactose It is expressed highly during infancy, but typically decreases as a child transitions to solid foods If the amount of lactase in the small intestine is insufficient to handle the lactose in the diet, some lactose will escape and enter the large intestine where bacteria will use it for energy Potential Link to T1D - A bacterial protein has a similar sequence to the human insulin epitope that contributes to the autoimmune response in T1D - This bacteria may trigger, modify, and prime an immune response to insulin & T1D onset The future of medicine Manipulating the microbiome may be the next frontier in medicine Imagine a designer bacteria that can synthesize a therapeutic in your gut in response to the presence of a pathogen Or a bacteria that can produce an enzyme or peptide hormone in the gut of an athlete that can provide a performance enhancing effect… What happens when we eat  - glucose , fatty acids & amino acids enter the blood supply from the intestines - The lver generally gets first access because of the portal vein - Insulin is released from the pancreas in response to high blood-glucose and glucagon is decreased - These changes in energy supply and hormone levels alters the way in which tissues use these nutrients The fate of our food Nutrients can either: 1.Broken down for energy – CATABOLISM 2.Used to make new molecules – ANABOLISM 3.Stored for use later The energy obtained from breaking down glucose, amino acids and fatty acids is converted to a usable form of ATP ATP contains high energy bonds that when broken, release energy that can be used to: Synthesize new molecules or Fuel cellular and bodily functions Glucose: Oxidized for energy Stored for later energy use as Glycogen (carbohydrate) or Triglyceride (lipid) Used to make new molecules Amino acids: Oxidized for energy Used to make new proteins or molecules CANNOT be stored, all protein is functional protein Fats: Oxidized for energy Stored for later energy use as Triglyceride (lipid) Used to make new molecules Glucose in the bloodstream is being used for energy or stored as glycogen/triglycerides Fatty acids are being stored as triglycerides in adipose tissue Amino acids are being used to make proteins or excess is used for energy Glucose is the most important energy source The brain and red blood cells can only use glucose for energy  Food → energy Once in a cells, nutrients are converted into energy Acetyl-CoA is the hub of energy production in a cell Glucose is converted into pyruvate through Glycolysis Pyruvate is then converted into Acetyl-CoA Amino acids are deaminated and converted into Acetyl-CoA Fats are oxidized into Acetyl-CoA Acetyl-CoA then enters the TCA cycle to be oxidized and produce electrons (NADH) The electrons enter the electron transport chain to produce ATP, converting Oxygen to Water in the process What happens to the waste? Metabolism produces waste that must be removed from the body, or it will be toxic Oxidation of macronutrients produces carbon dioxide, CO2 CO2 is exhaled by the lungs Deamination of amino acids produces ammonium, NH4 Nitrogenous waste is filtered out by the kidneys and excreted in the urine What happens when we are not eating? Glucose levels in blood must remain near constant to keep body processes functioning by supplying energy to brain and red blood cells Substances are metabolized differently depending on how long it has been since a meal In the fasted state, blood glucose levels are low Glucagon is released from the pancreas in response to low blood-glucose levels and insulin is decreased The body begins to use its energy stores to maintain blood glucose levels for the brain Maintaining energy supply Fatty acids are broken down, providing energy to tissues that do not rely on glucose Glycogenolysis begins - Liver stores of glycogen are converted to glucose, but are limited – this supply is exhausted first  Gluconeogenesis is the use of non-carbohydrate sources to produce glucose, this process ramps up as glycogen stores are being depleted Glycerol, lactate and amino acids can be used as precursors for glucose Proteins are broken down and instead of being remade, the amino acids are used for energy Ketone bodies are produced by the liver from fatty acids as an alternative energy source for some tissues Intermittent fasting Intermittent fasting involves limiting food intake to a set period and prolonging the fasted state After intermittent fasting diet intervention in individuals with patients with metabolic syndrome benefits were demonstrated Glucose metabolism: fasting blood glucose was reduced, glycated hemoglobin was reduced, insulin plasma levels were reduced, BMI decreased by 0.8 kg/m2. Lipid metabolism: reduced the total cholesterol level, reduced low-density lipoprotein level and reduced triglyceride levels What about starvation During a prolonged fasted state, blood glucose levels remain low, glycogen has been depleted and there is limited excess protein to breakdown The goal is to maintain an energy supply for essential tissues, the brain and red blood cells Ketone bodies build up in the blood from the breakdown of fatty acids. Once this concentration gets high enough the brain will begin using them for energy in addition to the limited glucose available When about 40% of body weight is lost, death due to starvation occurs The BMI for this is approximately 11 for women and 13 for men (30-50% protein loss, 70-95% of fat depleted) Blood and urine levels of the different substances are used to determine the metabolic state of the individual  Microbiology Nutrition Notes Year 3 Week 3 Carbohydrates & Lipids Acceptable Macronutrient Distribution Ranges (AMDR) is 45-65% RDA = 130 g/day This is the amount of glucose required by the brain to function Fruits, dairy, and whole grains consist of carbs in their natural, unrefined state Refining carbohydrates produces a more consistent ingredient, however this process reduces its nutrient content Refining removes parts of the grain that contain vitamins, minerals and fibre Whole Grains are: Bran Fibre and vitamins Germ Vegetable oils and vitamin E Endosperm Starch and some protein When a grain is refined, the endosperm is being collected Whole = whole fruit, seed, grain, vegetable Refined = purified carbohydrates such as flour, sugar, corn starch, syrup Carb Recommendations in Canada The World Health Organization (WHO) recommends that no more than 10% of Calories come from “free sugars” (sugars added in processing, also honey, syrups and fruit juices) The 2015 CCHS estimates that Canadians consume about 18% of Calories as total sugars (includes fruit, but much of the total sugar is from beverages and baked goods) Canada’s Food Guide recommends more unrefined carbohydrates – whole grains, fruits, vegetables and legumes What is too much sugar?  Regular consumption of sugar-sweetened beverages was associated with increased incidence of T2DM and may be linked to 4-13% of cases in the USA between 2010 and 2020 Long-term consumption of sugar-sweetened beverages was associated with mortality, primarily through cardiovascular disease A small reduction in the consumption of sugar-sweetened beverages could lead to a substantial decrease in the incidence of T2DM, cardiovascular disease and mortality Refined and unrefined sugar During photosynthesis, plants use energy from the sun to convert carbon dioxide (CO2) and water (H2O) into a carbohydrate (glucose) glucose, releasing oxygen (O2) Carbohydrates in their simplest and purest forms are monosaccharides Each monosaccharide has 6 carbons 12 hydrogens 6 oxygens C6H12O6 When two monosaccharides are combined, they form a disaccharides Oligosacchrides (3-10) and polysaccharides (10+) are formed when many monosaccharides are linked together This is how plants and animals can store carbohydrates for later use Refining means collecting carbohydrates in their purest form and removing any additional material (e.g. fibre, vitamins) What is fibre? di-, oligo- and polysaccharides are formed from condensations reactions using enzymes di-, oligo- and polysaccharides are broken down using hydrolysis reactions, again using enzymes A specific enzyme is needed to break down each type of glycosidic bond Fibre consists of polysaccharides that can’t be digested because there is no human enzyme to break it down Dietary fibre comes from the diet Functional fibre is added fibre due to beneficial impact Fibre and slowing nutrient absorption Dietary fibre can be “soluble” or “insoluble” Soluble fibre… forms a gelatinous solution with water in the intestine can be partly digested in large intestine by bacteria (e.g. oats, apples, beans)  Insoluble fibre… doesn’t dissolve in water (e.g. bran, peel of fruit and vegetables) and is excreted whole GI tract contents are diluted by soluble fibre making it more difficult for enzymes to interact with the food Results in slower digestion and absorption of nutrients Makes it more likely that cholesterol and bile acids will be excreted instead of absorbed… Fibre & Health Greater quantities of fibre in the diet will speed (decrease) the transit time but slow (increase) absorption time Time in small intestine 2-6 hours Time in large intestine 24-36 hours Stool weight is higher Research studies have shown a lower incidence of diseases such as cancer and CVD with higher fibre diets Physical activity, dietary intake of nuts, polyunsaturated fats and cereal fibre were inversely associated with mortality In a systemic review, high intake of dietary fibre was associated with “15–30% decrease in all-cause and cardiovascular related mortality, and incidence of coronary heart disease, stroke incidence and mortality, type 2 diabetes, and colorectal cancer”  Glucose + Oxygen à Carbon Dioxide + Water + Energy C6H12O6 + 6 O2 à 6 CO2 + 6 H2O + 4 ATP + 10 NADH (30 ATP) + 2 FADH (4 ATP) C6H12O6 + 6 O2 à 6 CO2 + 6 H2O + 38 ATP Availability of Carbs Controls Metabolism If carbohydrate is available, Acetyl-CoA from fatty acid oxidation has oxaloacetate to combine with in the TCA cycle If no carbohydrate is available, the liver metabolizes Acetyl-CoA to ketone bodies to provide energy for the brain Maintaining blood glucose levels The pancreases “senses” the level of sugar in the blood and releases insulin or glucagon to maintain blood sugar levels When blood glucose levels are high, glucose floods into the pancreas Beta cells release insulin into the blood and signal to other cells that glucose is available and should be used When blood glucose levels are low, alpha cells release glucagon, signaling the liver to release stored glucose These two hormones work to keep blood glucose in a normal range Using excess glucose  What is glycemic response & index? Glycemic response is the effect of a food on blood glucose levels Factors that impact glycemic response: Carbohydrate content of food Amount of protein, fat, fibre Activity level The ability for a food to increase our blood sugar is measure by glycemic index This is compared to the effect of pure glucose on our blood sugar High glycemic index = bigger increase in our blood sugar The ability for a food to increase our blood sugar is measure by glycemic index This is compared to the effect of pure glucose on our blood sugar High glycemic index = bigger increase in our blood sugar >70 = high GI 140/90 defines hypertension  Hypertension increases risk of cardiovascular disease, myocardial infarction and stroke Blood volume and blood pressure Diet and hypertension High intake of sodium can lead to increased blood volume and blood pressure High intakes of fibre, potassium, calcium and magnesium lower blood pressure Diuretics (AKA water pills) aid kidneys to release more sodium and water into urine Lifestyle factors are important in controlling hypertension is important Is caffeine a diuretic? Acute ingestion of caffeine can result in increased urine output in the short term However, tolerance develops in those who regularly consume caffeine Dietary approaches to stop hypertension DASH dietary pattern is a nutritional intervention to help manage hypertension The National Institutes of Health (NIH) conducted a study to see if a change in eating patterns would lower BP The combination of the DASH diet and low sodium intake lowered BP the most  Week 5 Water and fat-soluble Vitamins What are vitamins? Vitamins are organic compounds required to maintain health Many function in processes needed to maintain homeostasis, for growth or reproduction Vitamins are obtained in the diet through consumption of natural and fortified foods and supplements Bioavailability must be considered: a low-fat diet may inhibit absorption of fat-soluble vitamins carrier proteins may be required for transport provitamin forms may be absorbed requiring conversion to active form, interaction with other dietary components may also affect absorption Which foods contain vitamins? Canadians are not getting enough Vitamin C and Folate Fortification & enrichment Fortified foods have nutrients added that are NOT normally found in that food e.g. vitamin D in milk Enriched foods have nutrients added BACK that have been removed during processing e.g. enriched white flour Health Canada regulates which foods must be fortified and enriched Any nutrient added to a food must be listed on the nutrition label as well as the ingredient list Dietary supplements Supplements can be a source of vitamins in the diet Can contain a combination of vitamins, minerals, herbs, amino acids, botanicals, extracts Cannot replace foods consumed in the diet Caution should be exercised as regulation is not as stringent as for pharmaceuticals Toxicity can occur if consumption goes beyond established UL How are natural health products regulated? Health Canada’s Natural Health and Non-Prescription Products Directorate regulate the use of natural health products and non-prescription drugs  Licensed products that have been reviewed and approved for use by Health Canada have an eight-digit Natural Product Number (NPN) or Homeopathic Medicine Number (DIN-HM), which must appear on the label This license ensures that any claims are supported by scientific evidence, and it is produced using good manufacturing practice (GMP) NOTE: Health claims are usually related to dietary deficiency, not over-consumption How are vitamins absorbed? Approximately 40-90% of vitamins are absorbed in the small intestine Fat-soluble vitamins require dietary lipids for absorption Water-soluble vitamins may require transport molecules or specific molecules in GI tract Some vitamins are absorbed as an inactive pro-vitamin or vitamin precursor and must be converted into active forms Water-soluble vitamins Water-soluble vitamins are less likely to be present at toxic levels Their solubility in the blood allows them to be filtered out and excreted by the kidney when ingested in excess However, they tend to be less stable and tissue depletion can occur more readily Deficiencies first appear in rapidly growing tissues  Most are converted to co-enzymes that function in: - energy generation and - hematopoiesis (blood cell formation) The B vitamins Thiamine (vitamin b1) The first B-vitamin identified Added to food as enrichment/fortification RDA: 1.1-1.2 mg/day Toxicity: None Reported UL: Not determined - Bioavailability Sensitive to heat, oxygen, low-acid Anti-thiamin factors can destroy the vitamin in food (e.g. raw shellfish and coffee) - Use in the body Thiamine pyrophosphate (TPP, ThDP, TDP) Used in energy producing reactions where CO2 is released Used in the synthesis of acetylcholine (neurotransmitter) Used in the production is ribose, a precursor to RNA - Deficiency Beriberi  Characterized by lack of energy, weakness and neurological symptoms Thiamin deficiency can be a result of alcohol use disorder Can also result in a neurological condition called Wiernicke-Korsakoff syndrome - Supplementation Claims to increase energy, improve mental function, prevent heart disease Only if diet is deficient in thiamine Riboflavin (vitamin b2) Identified with thiamine Added to food as enrichment/fortification RDA: 1.1-1.3 mg/day Toxicity: None Reported UL: Not determined - Bioavailability Sensitive to light Opaque milk cartons are used to preserve riboflavin in milk - Use in the body Used to make FAD/FADH2, FMN Can transfer electrons to different molecules Used in energy producing reactions and transporting electrons to the electron transport chain Used in the conversion of other vitamins to active forms - Deficiency Riboflavin deficiency is rare Ariboflavinosis Increased alcohol consumption is associated with deficiency of many b vitamins Symptoms include poor wound healing, inflammation of the eyes, lips, mouth, and tongue and confusion - Supplementation Claims to increase energy, support eye and skin health Only if diet is deficient in riboflavin Niacin (vitamin b3) Identified during study of pellagra Associated with diets that relied on corn Added to food as enrichment/fortification  RDA: 14-16 mg NE/day Toxicity: Flushing, nausea, rash, tingling extremities UL: 35 mg/day from fortified food/supplements - Bioavailability Can be made in the body from the amino acid tryptophan, but only when there is enough tryptophan for protein synthesis - Use in the body NAD+/NADH; NADP+/NADPH Transfers electrons to other molecules Used as an electron transporter to generate ATP (energy) Use in the body so widespread that deficiency causes damage throughout the body - Deficiency Pellagra is the result of diet deficient in niacin Symptoms are 3 D’s: dermatitis, dementia and diarrhea If left untreated, results in death - Supplementation Claims to increase energy Only if diet is deficient in niacin Biotin Identified in animal studies with rats fed protein from raw egg NO RDA à AI: 30 µg/day Toxicity: None Reported UL: Not determined - Bioavailability Biotin is also produced by bacteria in the GI tract and absorbed into the body Food containing raw egg should be avoided because the protein avidin in the egg white binds biotin very tightly, making it unavailable for absorption - Use in the body Co-enzyme for enzymes that add a –COOH group to molecules Used to generate molecules needed for citric acid cycle and glucose synthesis - Deficiency Deficiency is rare Symptoms including nausea, thinning hair, loss of hair colour, a red skin rash, depression, lethargy, hallucinations, and tingling of the extremities gradually appear. - Supplementation Claims to treat hair loss, brittle nails  Only if diet is deficient in biotin Pantothenic acid Widely available in food NO RDA à AI: 5 mg /day Toxicity: None Reported UL: Not determined - Bioavailability Susceptible to heat and low- or high-acid conditions - Use in the body Part of Coenzyme A (CoA), an important part of Acetyl-CoA Used in the synthesis of cholesterol - Deficiency Deficiency is rare Can occur as part of multiple B-vitamin deficiency Vitamin B6 Identified when a deficiency syndrome was discovered that didn’t respond to thiamine or riboflavin Needed for over 100 enzymatic reactions Added back to food as enrichment/fortification RDA: 1.3-1.7 mg/day, increasing with age Toxicity: Numbness, nerve damage UL: 100 mg/day - Bioavailability Easily destroyed by heat and light Easily lost during processing - Use in the body Used in amino acid metabolism Used in transamination and deamination reactions Needed to synthesize hemoglobin Needed to form white blood cells Needed for the conversion of tryptophan to niacin Metabolism of glycogen Synthesis of neurotransmitters Synthesis of myelin coating on nerves - Deficiency  Neurological symptoms include depression, headaches, confusion, numbness and tingling in the extremities, and seizures Anemia Other deficiency symptoms such as poor growth, skin lesions, and decreased antibody formation may occur because vitamin B6 is important in protein and energy metabolism - Supplementation Potential link to reduced cardiovascular disease (reduced levels of homocysteine) Potential link to improved immunity in older adults Folate Identified as a group of compounds that were part of Wills Factor and used to treat anemia during pregnancy Added to food as enrichment/fortification RDA: 400 µg DFE/day increased to 600 µg DFE/day during pregnancy Toxicity: None reported, but high intake may mask vitamin B12 deficiency UL: 1000 µg DFE/day - Bioavailability Folate in the diet is bound to chains of the amino acid glutamate, which must be removed prior to absorption Estimated that only 50% of dietary folate is absorbed Synthetic folate (supplements and fortification) does not contain the poly-glutamate chain and is more readily absorbed - Use in the body Used in amino acid metabolism Used in the synthesis of DNA nucleotides – needed for DNA replication Used in the methylation of DNA – silencing of gene expression - Deficiency Megaloblastic anemia due to inability for cells to divide Neural tube defects, such as spina bifida, anencephaly Heart disease (increased homocysteine levels) - Supplementation Supplemental folate masks Vitamin B12 deficiency Because the risk of neural tube defects usually occurs prior to confirmation of pregnancy (~28 days gestation), it is advised the persons of child-bearing years to take a folate supplement Fortification in foods has dramatically decreased the rates of neural tube defects in infants Vitamin B12 Pernicious anemia is caused by an inability to absorb sufficient vitamin B12 RDA: 2.4 µg/day Toxicity: None reported UL: No data - Bioavailability Found almost exclusively in animal products It can be made by bacteria and fungi but not by plants and animals Individuals who follow a vegan dietary pattern must get vitamin B12 from nutritional yeast or a supplement Vitamin B12 is inaccessible within food prior to digestion. In the stomach, acid and pepsin release it from bound proteins in food In the small intestine, it is bound to intrinsic factor, allowing it to bind to receptors in the ileum and be absorbed Very little vitamin B12 is lost in the body, therefore deficiency develops slowly - Use in the body Used in amino acid metabolism and the synthesis of methionine Regenerates folate - Deficiency Pernicious anemia due to inability to regenerate folate Neurological symptoms, which include numbness and tingling, abnormalities in gait, memory loss, and disorientation If left untreated this eventually causes paralysis and death Atrophic gastritis – reduction in the amount of stomach acids impairs the ability to release vitamin B12 from food Vegan dietary patterns, due to lack of animal-based foods, must get it from fortified food or nutritional yeast Heart disease (increased homocysteine levels) - Supplementation Supplemental folate masks Vitamin B12 deficiency Advised for persons following a vegan dietary pattern Claims include “pick-me-up” for tired individuals Only if someone is deficient in vitamin B12 Dietitians estimate that 1/3 of the population may have low vitamin B12 levels  Supplementation needed, especially in vegetarians and the elderly Vitamin C Vitamin C deficiency was identified as causative for Scurvy RDA: 75-90 mg/day Toxicity: Extreme doses may cause diarrhea, nausea, and abdominal cramps UL: 2000 mg/day - Bioavailability Vitamin C is unstable and is destroyed by oxygen, light, and heat Reactive with copper or iron cooking utensils and by low-acid conditions. - Use in the body Aids in the synthesis and maintenance of connective tissue stemming from the formation of collagen Crosslinks collagen proteins to form stronger fibers Synthesis of neurotransmitters, hormones, bile acids Aids in the synthesis and maintenance of connective tissue stemming from the formation of collagen Synthesis of neurotransmitters, hormones, bile acids Acts as an anti-oxidant Supports immune system Aids in absorption of iron - Deficiency Scurvy Collagen can’t be maintained, and connective tissue breaks down, wounds heal poorly, weakening blood vessels (bleeds) Poor iron absorption = anemia - Supplementation Prophylactic Vitamin C supplementation may reduce the duration of a cold Role as an anti-oxidant and in bile acids production suggests a potential to decrease or protect against cardiovascular disease – so far evidence is lacking Potential role in cancer prevention Higher intake of fruits and vegetables (high vitamin C) decreases the risk of cancer. Maybe linked to antioxidants?  More likely due to a better dietary pattern and not vitamin C alone Oxygen Free radicals Oxygen is necessary for life but can be toxic as well Free radicals can enter our bodies from foods and environmental toxins Free radicals are also generated routinely by metabolic processes (e.g. ETC) and inflammation Free radicals can damage cell membranes, DNA, proteins and mitochondria These processes are implicated in aging and diseases such as cancer and cardiovascular disease Neutralization of free radicals minimizes the possible damage How are vitamins absorbed? Approximately 40-90% of vitamins are absorbed in small intestine Fat-soluble vitamins require dietary lipids for absorption Water-soluble vitamins may require transport molecules or specific molecules in GI tract Some vitamins are absorbed as an inactive pro-vitamin or vitamin precursor and must be converted into active forms Fat-soluble vitamins Requirement for dietary fat and bile acids for absorption in the intestine Chylomicrons are the transport system for these molecules, travel with triglycerides in the lymph to enter bloodstream Fat-soluble vitamins able to be stored in body in adipose tissue. This increases the danger of these vitamins building up to toxic levels, but decreases the risk of deficiencies developing Vitamin A Vitamin A is important for vision Can be found as a per-formed or pro-vitamin In Canada, dairy products are fortified with Vitamin A RDA: 700-900 µg/day Toxicity: Headache, vomiting, hair loss, liver damage, skin changes, bone and muscle pain, fractures, birth defect UL: 3000 µg/day pre-formed vitamin A - Bioavailability Must be released from food by acidity and enzymes  Stable when heated, but destroyed by exposure to light and oxygen Combines with bile and fats to be absorbed 70-90% of pre-formed vitamin A is absorbed, pro-vitamin A (i.e. β-carotene) is less absorbed - Use in the body Stored in the liver Must be transported in the blood by a carrier protein, retinol-binding protein Acts as an anti-oxidant Critical to vision and the conversion of light to signals in the brain Control of gene transcription and cell differentiatio - Deficiency Impaired vision, including night blindness Impaired cell differentiation Increased keratin production Impaired immunity Impaired growth and development Not common in developed countries, but most common in India, Africa, Latin America and the Caribbean - Supplementation Can be toxic at extreme doses Retinoic Acid (Retin A, Accutane) used to treat acne, wrinkles due to sun damage Increases turnover of cells Can have side effects Carotenoids (pro-vitamin A) are less toxic as our body will stop absorbing them when levels are high - Golden rice A strain of rice genetically modified to produce β-carotene Has to potential to reduce the impact of vitamin A deficiency in low-income regions Caught up in the pushback against GMO foods Are GMOs Good or Bad? Vitamin D Vitamin D is known as the sunshine vitamin, can be produced in the skin using radiation from the sun Vitamin or hormone? When exposure to the sun is low, must be consumed in the diet In Canada, foods are fortified with Vitamin D, including dairy products RDA: 15-20 µg/day Toxicity: Calcium deposits in soft tissues, growth retardation, kidney damage UL: 100 µg/day - Bioavailability Major source is exposure to sunlight Animal products contain Cholecalciferol (Vitamin D3) - Use in the body Made from cholesterol and converted into Vitamin D3 in the skin Vitamin D3 is consumed in the diet from animal products Vitamin D3 circulates in the blood but is in and inactive form Processing in the liver and kidney produces the active for of vitamin D Vitamin D levels work with parathyroid hormone to control calcium levels in the body - Deficiency Calcium absorption is inadequate without vitamin D so bones form poorly Deficiency results in rickets in children Breastmilk is deficient in Vitamin D so supplementation is recommended Osteomalacia is manifestation of Vitamin D deficiency in adults – results in greater risk of bone fracture, muscle and bone pain Individuals who follow a vegan or vegetarian dietary pattern appear to be at greater fracture risk Those living above 40° latitude N and below 40° South receive insufficient UV radiation for Vitamin D synthesis It is estimated that there are a billion people throughout the world who are vitamin D deficient - Supplementation In Canada, supplements recommended for several groups Breastfed infants until they can consume vitamin D in their diet Higher for those living in northern Canada during the winter north (above 55° latitude, approximately Edmonton) All Canadians over 50 Vitamin D supplements do not appear to reduce fracture risk in adults with no other risk factors for fractures Vitamin E Identified as a fat-soluble vitamin required for fertility in lab rats Anti-oxidant RDA: 15 mg/day Toxicity: relatively non-toxic but can inhibit vitamin K activity (blood clotting) UL: 1000 mg/day from supplements - Bioavailability Sensitive to destruction by oxygen, metals, light, and heat  Much is lost during processing - Use in the body Incorporated into chylomicrons and transported throughout the body Transfer proteins in the liver incorporate vitamin E into VLDL particles for delivery Scavenges free radicals before damage to unsaturated fatty acids in lipid membrane; also protects proteins; DNA from oxidative damage Vitamin E’s antioxidant function is regenerated by Vitamin C - Deficiency Deficiency is rare Vitamin E deficiency is usually characterized by neurological symtoms associated with nerve degeneration Symptoms observed in humans include poor muscle coordination, weakness, and impaired vision Newborns and especially infants born premature have low vitamin E Most Vitamin E transfer occurs in the last weeks of pregnancy Increased risk of hemolytic anemia because RBC membranes are less stable - Supplementation Although deficiency is rare, supplement promote are promoted for: hair growth restore, maintain, or increase sexual potency and fertility; alleviate fatigue; maintain immune function; enhance athletic performance; reduce the symptoms of premenstrual syndrome (PMS) and menopause; slow aging No evidence to support these claims when nutritional needs are being met Vitamin K Chickens feed a fat-free diet developed a bleeding disorder Named for koagulation, the Danish word for coagulation No RDA, AI: 90-120 µg/day Toxicity: Can interfere with anti-coagulant drugs UL: Not-determined - Bioavailability Vitamin K is destroyed by exposure to light and low or high-acid conditions Vitamin K can be produced by bacteria in the human gut, but not enough for dietary needs - Use in the body  Vitamin K is necessary to enable blood clots to form Clotting Factors II, VII, IX and X require carboxylase modification to function The enzymes that add this modification use Vitamin K as a cofactor. If Vitamin K is not present, these modifications don’t occur These clotting factors can’t bind to platelets and can’t stimulate the formation of fibrin, forming a blood clot - Deficiency Abnormal blood coagulation – Blood does not clot, and uncontrolled bleeding occurs Deficiency is rare but may occur due to fat malabsorption or long-term use of antibiotics Most common in newborns because of low transfer from mother to infant Newborn gut is free of bacteria, no vitamin k is made there Infants typically injected with vitamin k with 6 hours of birth - Supplementation Injections of vitamin K pre-surgery to aid in blood clotting Since blood clots contribute to strokes and heart attacks, vitamin k antagonists are used to prevent blood clots (Warfarin AKA Coumadin)