Chapter 4 Carbohydrates PDF

Chapter 4: Carbohydrates Alyson Gaylord, MS, RD Potatoes Good for heart health Great for gut health Alters gut microbiota composition and diversity Full of nutrients High in potassium (helps the function of your nerves, muscles and heart) Eat your potatoes!!! Chapter Outl...

Chapter 4: Carbohydrates Alyson Gaylord, MS, RD Potatoes Good for heart health Great for gut health Alters gut microbiota composition and diversity Full of nutrients High in potassium (helps the function of your nerves, muscles and heart) Eat your potatoes!!! Chapter Outline Overview of Carbohydrates Forms of Carbohydrates Carbohydrates in Foods Making Carbohydrates Available for Body Use Putting Carbohydrates to Work in the Body Carbohydrate Needs Nutrition & Your Health: Diabetes PART 1 Carbohydrates Overview Main fuel source for: Brain Nervous system Red blood cells 4 kcal/g Carbohydrates are readily available as fuel for all cells in the form of: Blood glucose Glycogen Stored in muscle and liver Carbohydrates Overview The Food and Nutrition Board recommends consuming 45%-65% of total daily calories as carbohydrates It is recommended to consume carbs in the forms of: Whole grains Fruits Vegetables Legumes Forms of Carbohydrates - Overview Simple sugars: simple forms of carbohydrates Monosaccharides Disaccharides Polysaccharides: complex forms of carbohydrates Starches (digestible) Fibers (indigestible) On Nutrition Facts Label: “Total Sugars” “Added Sugars” Monosaccharides Mono = one Basic unit of all sugar structures Glucose, fructose, and galactose Monosaccharides Glucose: Major monosaccharide found in the body Also known as dextrose or blood sugar Mostly comes from the breakdown of starches and sucrose (table sugar) Almost all CHO are converted to glucose in the liver Monosaccharides Fructose: Also called fruit sugar Absorbed by the small intestines and transported to the liver for metabolism Converted to glucose or other compounds, such as fat Most free fructose consumed is high-fructose corn syrup (HFCS) in highly processed foods Monosaccharides Galactose: Large quantities of pure galactose are not found in nature; most found bound to glucose as part of lactose Absorbed and transported to liver Converted to glucose or glycogen Disaccharides Two monosaccharides bonded together: di means “2” Sucrose, lactose, maltose Disaccharides Sucrose: Glucose and fructose bonded together Found naturally in sugarcane, sugar beets, honey, and maple syrup Lactose: Glucose and galactose bonded together Milk is the major source Lactose intolerance: when a person cannot readily digest lactose Disaccharides Maltose: Glucose and another glucose molecule bonded together Important in the beer and liquor industry Small amounts of maltose can be found in some foods, including fruits, vegetables, and breads Polysaccharides Poly = many Polysaccharides may contain 1000 or more glucose units bonded together in chains Starch, glycogen, fiber Polysaccharides Starch: Found mostly in grains, vegetables and fruits Plants store carbohydrates in 2 forms that are digestible by humans: amylose and amylopectin Amylose: comprises 20% of digestible starch consumed Amylopectin: comprises 80% of digestible starch consumed Polysaccharides Glycogen: Storage form of carbohydrates Highly branched chain for quick energy About 1800 kcal of glycogen are present in the human body at any given time Major storage sites: Liver (400 kcal) – used to maintain blood glucose Muscle (1400 kcal) – used to fuel muscle cells, especially during high- intensity or endurance exercise Polysaccharides Fiber: Differ from starches because the bonds that hold the sugar units together are indigestible by humans, and cannot be absorbed Plant foods contain naturally occurring dietary fiber as a combination of both insoluble and soluble fiber in different proportions Beans, peas, lentils, fruits, nuts, seeds, vegetables, wheat bran Whole grains (e.g., whole oats, brown rice, popcorn, quinoa) Foods made with whole grain ingredients (e.g., breads, cereals, crackers, pasta) Carbohydrate Concept Map Carbohydrates in Foods – Overview MyPlate nutrient-dense sources of carbohydrates include: Grains Vegetables Fruits Dairy Carbohydrates in Foods – Overview Rich sources of starch include plant-based foods (beans, potatoes, grains) These provide micronutrients, phytochemicals, and fiber Soluble fiber found in the skins and flesh of many fruits and berries; as thickeners or stabilizers in jams, yogurts, sauces, and fillings Fiber is available as a supplement or functional fiber added to food Top sources of carbohydrates for US adults: Sugar-sweetened beverages Desserts Sweet snacks The Dietary Guidelines recommends limiting added sugars to less than 10% of total calories per day Carbohydrates in Foods – Whole Grains From the Dietary Guidelines: Make at least 1/2 of your grains whole Replace refined grains with whole grains Limit consumption of refined grains, especially those with added sugars, solid fats, and sodium Whole grains consist of the bran (main source of fiber in grains), endosperm, and germ Refined grains only contain endosperm Carbohydrates in Foods – Whole Grains When whole grain is used on a food package, it means that the product contains a minimum of 51% of whole grain ingredients by weight per serving Examples of whole grains Amaranth Quinoa Barley Dark rye Brown rice and wile rice Whole-grain cornmeal, whole-grain Buckwheat cereals, and crackers Bulgar Whole-wheat bread Millet Oats Popcorn Carbohydrates in Foods – Whole Grains Compared to refined grains, whole grains provide more: Dietary fiber Iron B-vitamins Health advantages of consuming whole grains: Decreased risk of cardiovascular disease Decreased risk of diabetes Decreased risk of metabolic syndrome Decreased risk of some cancers Decreased risk of obesity Maintain a healthy gut microbiota Carbohydrates in Foods – Whole Grains Highlighted as a nutrient of public health concern About 98% of Americans one year of age or older not meeting recommendations Carbohydrates in Foods – Vegetables Provides carbohydrates in the form of starch and fiber Naturally low in fat and calories Provide the following micronutrients: Potassium Folate Vitamin A Vitamin C Within the Dietary Guidelines, any vegetable or 100% vegetable juice counts as a member of the vegetables group Carbohydrates in Foods – Vegetables 5 subgroups Dark-green Starchy Red and orange Beans, peas, lentils Other vegetables Close to 90% of the U.S. population does not meet the Dietary Guidelines recommendations for vegetables Carbohydrates in Foods – Fruit Provide carbohydrates in the form of natural sugar and fiber MyPlate food group includes whole fruits (canned, frozen, and dried forms) and 100% fruit juice About 80% of the U.S. population does not meet the fruit recommendations Carbohydrates in Foods – Dairy MyPlate dairy group includes fat-free and low-fat (1%) milk, yogurt, cheese and fortified soy alternatives Not included in the MyPlate dairy group Plant-based dairy alternatives (e.g., almond, rice, coconut, oat, and hemp “milks”) – may or may not be fortified with calcium, vitamins A and D, and are typically lower in protein than cow’s milk Foods made from milk that are primarily fat (e.g., cream cheese, cream, butter) Carbohydrates in Foods – Dairy Approximately 90% of the U.S. population does not meet the MyPlate dairy recommendations Dairy in the United States is often consumed in combination dishes high in sodium, saturated fat, and added sugars Ex. pasta dishes made with cream Lactose in Common Dairy Foods Carbohydrates in Foods – Nutritive Sweeteners Sugars High-fructose corn syrup (HFCS) Honey Agave nectar Brown sugar: sucrose + molasses Turbinado (raw sugar): partially refined raw sucrose Maple syrup Concentrated sugar of maple tree sap Most commercial “maple” syrups are corn syrup and HFCS with flavoring Nutritive Sweeteners – Sugars All monosaccharides and disaccharides are nutritive sweeteners because they provide calories The Dietary Guidelines recommends a reduction of calories from added sugars (no more than 10% of calories per day) Average intake is almost 270 calories (13%) per day Almost 40% of added sugars come from sugar-sweetened beverages (e.g., soft drinks, fruit drinks, sports and energy drinks, and sweetened coffee and tea), followed by desserts and sweet snacks The amount of added sugars in a food must be present on the Nutrition Facts label Nutritive Sweeteners – High Fructose Corn Syrup Found in a wide variety of foods Sweetener with 55% fructose (sucrose has 50% fructose) Made by treating cornstarch with acid and enzymes to break some of the glucose into fructose Benefits include: Low cost Broad range of food-processing applications Ease of transport Shelf stability Improved food properties No metabolic of endocrine response differences between HFCS and sucrose for obesity or adverse health outcomes Nutritive Sweeteners – Honey Plant nectar altered by bee enzymes Fructose and glucose Not safe for infants because bacterial spores from bacterium Clostridium botulinum can cause fatal foodborne illness Consuming local honey can help to improve immune system Increases number of white blood cells in the body Nutritive Sweeteners – Agave Nectar Comes from the plant used to make tequila Highly processed Sweeter than granular sugar, so you can use less Nutritive Sweeteners – Alternative Sweeteners Alternative, artificial, high-intensity, low-calorie, or nonnutritive sweeteners Yield few or no calories (in amounts typically used) High-intensity sweeteners are regulated as food additives, unless their use as a sweetener is generally recognized as safe (GRAS) A growing number of alternative sweeteners are currently available in the United States Acesulfame-K Advantame Allulose Aspartame (Equal) Saccharin (Sweet ‘N Low) Stevia Sucralose PART 2 Chapter 4 Review Questions What is carbs the main fuel source for? Chapter 4 Review Questions What is carbs the main fuel source for? Answer: brain, nervous system, red blood cells Chapter 4 Review Questions Carbs are readily available as fuel in the form of... Chapter 4 Review Questions Carbs are readily available as fuel in the form of... Answer: blood glucose and glycogen (storage form) Chapter 4 Review Questions Where is glycogen (storage form of glucose) stored? Chapter 4 Review Questions Where is glycogen (storage form of glucose) stored? Answer: muscle and liver  Chapter 4 Review Questions Which My Plate food group is the least abundant source of carbs?  Chapter 4 Review Questions Which My Plate food group is the least abundant source of carbs? Answer: protein  Chapter 4 Review Questions Name the two forms of simple sugars and the two forms of polysaccharides.  Chapter 4 Review Questions Name the two forms of simple sugars and the two forms of polysaccharides. Answer: simple sugars – monosaccharides + disaccharides; polysaccharides – starches + fibers  Chapter 4 Review Questions What is the major monosaccharide found in the body?  Chapter 4 Review Questions What is the major monosaccharide found in the body? Answer: glucose  Chapter 4 Review Questions Which two monosaccharides combine to form sucrose?  Chapter 4 Review Questions Which two monosaccharides combine to form sucrose? Answer: glucose and fructose  Chapter 4 Review Questions What sweetener is used widely due to its low cost, ease of transport and shelf stability?  Chapter 4 Review Questions What sweetener is used widely due to its low cost, ease of transport and shelf stability? Answer: high-fructose corn syrup Making Carbohydrates Available for Body Use – Starch and Sugar Digestion Food preparation may be viewed as the start of digestion Mouth Starch digestion begins (minor contribution) Salivary amylase breaks down starch into disaccharides Stomach: salivary amylase inactivated by stomach acid Small intestine Alklaline environment promotes carbohydrate digestion Pancreas releases enzymes (e.g., pancreatic amylase) to break down polysaccharides to di- and monosaccharides Enzymes attached to intestinal cells digest disaccharides to monosaccharides Maltase acts on maltose Sucrase acts on sucrose Lactase acts on lactose Making Carbohydrates Available for Body Use – Lactose Intolerance Deficient production of lactase enzyme impairs digestion of lactose Lactose maldigestion Symptoms are experienced by about 68% of the world’s population Symptoms of bacterial fermentation of lactose Bloating Abdominal pain (cramping) Gas Diarrhea Use of low-lactose dairy products or lactase-containing products (e.g., aged cheeses, yogurt) decreases symptoms Lactase supplements can make lactose more tolerable Making Carbohydrates Available for Body Use – Fiber & Intestinal Health Fiber is indigestible Adds mass to feces Stimulates intestinal muscles and eases elimination Attracts water to soften stool Health risk of excess fiber (≥60 g/day) Intestinal blockage Decreased mineral availability (i.e., zinc, calcium, magnesium, iron) Possible decreased risk of colon cancer with increased fiber intake, but may be due to other nutrients in fiber-rich foods Putting Carbohydrates to Work in the Body – Providing Energy Supply calories to fuel the body (4 kcal/g) Red blood cells can only use simple carbohydrates Brain and central nervous system use glucose but can use ketone bodies Muscles fueled by glucose but can also use fat or protein Adequate carbohydrate intake spares protein from use as an energy source and prevents ketosis When carbohydrates are not consumed in adequate amounts: Proteins are converted to glucose and therefore are not available for other functions Fats are not metabolized completely, forming ketone bodies (ketosis), which can disturb acid-base balance Any weight-loss regimen should provide at least the RDA for carbohydrate Therapeutic ketogenic diets have proven effective for treating epilepsy Putting Carbohydrates to Work in the Body – Regulating Blood Glucose Blood glucose is maintained within a very narrow range by the liver and pancreas Pancreas releases insulin when blood glucose rises Insulin directs liver to store glucose as glycogen Insulin directs muscle, adipose, and other cells to take up glucose Pancreas releases glucagon when blood sugar falls Keeps blood sugar from falling too low Prompts liver to break down glycogen to glucose Putting Carbohydrates to Work in the Body – Regulating Blood Glucose This complex regulatory system safeguards against high blood glucose (hyperglycemia) and low blood glucose (hypoglycemia) Carbohydrate Needs – Overview RDA for adults: 130 g/day Based on the needs for brain and central nervous system without relying on ketones as an energy source Exceeding this amount is fine Food and Nutrition Board recommends 45%-65% of calories as CHO Diabetes – Overview Hyperglycemia: high blood sugar Hypoglycemia: low blood sugar Diabetes affects 10.5% of the U.S. adult population 20 years or older Many people (>21%) with diabetes are unaware of their condition The American Diabetes Association (ADA) recommends testing fasting blood glucose in adults over age 45 every 3 years to screen for diabetes asymptomatic individuals Hemoglobin A1c: more sensitive, long-term indicator of blood glucose control vs. fasting glucose Reflects about 3 months worth of blood glucose levels HbA1c ≥ 6.5% is often used to diagnose diabetes Diabetes – Overview Diabetes – Pre-Diabetes Condition for individuals whose blood glucose levels do not meet criteria for diabetes but are higher than normal Also called impaired fasting glucose Reversible Changing dietary patterns Increasing physical activity Diabetes Types of diabetes Type 1 diabetes: insulin-dependent Juvenile onset Type 2 diabetes: non-insulin-dependent Adult onset Gestational diabetes Occurs during pregnancy and usually resolves after birth of baby Increases maternal risk for developing type 2 diabetes later in life Diabetes – Type 1 Diabetes Disease characteristics Often occurs in childhood but can occur at any age Usually admitted to hospital with high blood glucose and ketosis Most cases begin with an immune system disorder that destroys the insulin-producing cells of the pancreas Decreased release of insulin from the pancreas Treatment: insulin therapy Type 1 Diabetes – Risks Risks Cardiovascular disease Nerve damage Mostly in extremities Loss of sensation means not recognizing sores or injuries Blindness Kidney disease Diabetes – Type 2 Diabetes Disease characteristics Usually begins after age 45 Most common type; 90%-95% of cases Incidence rising, especially in children and young adults Risk factors: both genetic and environmental Family history Older age Obesity, physical inactivity Prior history of gestational diabetes Race or ethnicity Latino/Hispanic Americans, African Americans, Asian Americans, Native Americans, Pacific Islanders Type 2 Diabetes – Treatment Primary goal: achieve healthy weight Oral medications or insulin injections Regular patterns of meals and physical activity Medical nutrition therapy Increased intakes of plant-based and fiber-rich foods and fish Reduced intake of added sugars and saturated fats Consume 25-38g fiber daily Include heart healthy food choices Hypoglycemia Early symptoms: Shakiness Sweating Palpitations Anxiety Hunger Late symptoms result from insufficient glucose reaching the brain Mental confusion Extreme fatigue Seizures Unconsciousness