Carbohydrates - PowerPoint PPT Presentation

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  1. Carbohydrates

  2. Roles of Carbohydrates • Definition: organic substance made of carbon, hydrogen, and oxygen that supplies the body’s main source of energy • Macronutrient • Direct energy source- 4 kcal per gram • Adequate carbohydrate intake preserves tissue protein • Fuel for the central nervous system (CNS) and red blood cells • Prevents ketosis

  3. Role of Carbohydrates • Sufficient carbohydrates prevent the rapid breakdown of fat that would produce ketones • Ketones are chemicals produced by the liver when the body cannot use glucose and must break down fat for energy • Ketones can poison and even kill body cells. • When ketones build up, the body gets rid of them in the urine • Ketosis slows down fat metabolism

  4. Ketones • During long-term starvation, proteins in the muscles, heart, liver, kidneys and other vital organs break down into amino acids and certain forms are turned into needed glucose. • Overtime these organs become partially weakened. • Ketones that accumulate in the body over long periods of time can lead to serious illness and coma. • Eventually ketone buildup can develop into ketosis and the ketone bodies will disrupt the body’s normal acid-base balance

  5. Function of CHO’s • Low glycogen stores or inadequate carbohydrates intake may cause cardiac disorder and angina (chest pain) • Central Nervous System (brain and spinal cord) has no stored supply of glucose; therefore it is dependent on a minute-to-minute supply of glucose

  6. Nature of Carbohydrates • Reaction driven by energy from the sun reacting with chlorophyll • Photosynthesis: transforms solar energy into carbohydrates • H20 + CO2 chlorophyll Glucose

  7. Energy Production System • Digestion of CHO’s is broken down into glucose • Absorption of glucose goes through the blood circulation • Insulin allows for glucose utilization into the cells • Glucose is burned in the mitochondria making ATP through cellular respiration

  8. Mitochondria • Produces ATP from glucose • Found in all cells

  9. Classes of CHO’s • Carbohydrate = sugar • Saccharide means sugar in Latin • Classified according to sugar units • Monosaccharide: one sugar molecule • Disaccharides: two sugar molecules • Polysaccharides: chains of sugar molecules, usually glucose

  10. Monosaccharides • Glucose- C6H12O6 • Fructose- C6H12O6 • Galactose- C6H12O6

  11. Glucose • Glucose is also called dextrose or blood sugar • Used directly by the cell for energy • Stored as glycogen in the muscles and liver • Converted to fat and stored for energy

  12. Fructose • Fructose is also called levulose or fruit sugar • Absorbed in the small intestine and transported to the liver where it is quickly metabolized and converts to glucose • Can form into fat if consumed in high-amounts • Often found in fruits

  13. Galactose • Galactose forms milk sugar called lactose • Large quantities of pure galactose do not exist in nature • The body converts galactose to glucose for energy metabolism

  14. Disaccharides • Combining two monosaccharide molecules forms a disaccharide • Each disaccharide includes glucose as a principle component • Sucrose: Common table sugar (glucose + fructose) • Lactose: The sugar in milk and not found in plants (glucose + galactose) • Maltose: Not found in diet. An ingredient used during the production of alcohol. (glucose + glucose)

  15. Polysaccharides • Starch and fiber are two common forms of plant polysaccharides • Starch - Plant starch accounts for approximately 50% of the total carbohydrate intake of Americans - The term “complex carbohydrate”commonly refers to dietary starch

  16. Fiber • Fiber is a polysaccharide • Humans lack the necessary enzymes (a protein that accelerates a specific chemical reaction without altering itself ) to digest fiber • No direct energy value • Fibers can be water-soluble: gums and pectin • Water-insoluble: cellulose, hemicellulose, and lignin

  17. Water Soluble Fiber: Mixes well with water Slows digestion Can help with weight loss Helps regulate blood sugar levels and cholesterol Water Soluble vs Water Insoluble Fiber

  18. Water Soluble vs Water Insoluble Fiber • Water Insoluble Fiber: • Is not soluble in water. No physical change when it enters small intestine. • Passes through our digestive system in close to its original form • Helps to prevent constipation, colon cancer and other digestive diseases

  19. Food labels with Dietary Fiber and with Soluble/Insoluble Fiber

  20. Roles of Fiber • Retains considerable water and thus gives bulk to the food residues in the intestines • Binds or dilutes harmful chemicals • Shortens transit time for food residues (and possibly carcinogenic materials) to pass through the digestive tract • There is no RDA for soluble and insoluble fiber. • There is an RDA for overall fiber. It is best advised to get a good combination of both

  21. RDA= 20-40 grams daily Common sources of soluble fiber: Barley Oatmeal Oatbran Apples Bananas Blackberries Oranges Grapefruit Broccoli Brussel Sprouts Carrots Nectarines Peaches Pears Plums Prunes Black Beans Kidney Beans Navy Beans Black Eyed Peas Lentils Chickpeas Fiber Intake and Sources

  22. Fiber Intake and Sources Common sources of insoluble fiber: Bell Peppers Potatoes Peas Pineapple Skins of fruits and vegetables Whole-wheat and whole-grain products • Wheat Bran • Green Beans • Corn • Seeds and Nuts • Strawberries • Raisins • Spinach • Cucumbers • Tomatoes • Granola

  23. Other Health Benefits of Fiber • Increases satiety (feeling full), which aids in obesity prevention • Promotes normal bowel function • Adds bulk to stool • Slows glucose absorption-reducing blood glucose spikes and reducing insulin secretion • Prevents and helps manage diverticulosis

  24. Diverticulosis • Diverticulosis: • A condition marked by small sacs or pouches (diverticula) in the walls of an organ such as the stomach or colon. These sacs can become inflamed and cause a condition called diverticulitis, which may be a risk factor for certain types of cancer.

  25. Carbohydrates Stored as Glycogen • Glycogen is the storage polysaccharide found in mammalian muscle and liver • Glycogen is synthesized from glucose during gluconeogenesis • Glycogenolysis is the reconversion process; it provides a rapid extra muscular glucose supply

  26. Digestion of Carbohydrates • Mechanical Digestion: Muscular contractions called peristalsis break food mass into smaller particles • Chemical Digestion: Enzymes break down food into smaller particles • Chemical and Mechanical Digestion begins in the Mouth • Mastication: Chewing

  27. Digestion of Carbohydrates • Chewing mixes with saliva to start the breakdown of starch • Stomach: mechanical digestion only, 20-30% of carbohydrates have been converted to maltose • Small Intestine: Chemical digestion is completed here by enzymes from the pancreas and intestine

  28. Body Needs for Carbohydrates • 45% -65% daily or 225-325 g based on a 2,000 calorie/ day diet • 20-40 grams of fiber daily • Limit sugar to no more than 25% of total calories

  29. Refined Carbohydrates • “Refined,” when referring to processed carbohydrates, means they have been stripped of their fiber and the many nutrients now known to be cancer-fighters, critical for heart health, helping to stabilize blood sugar and even enhance bone health. • Necessary nutrients like Vitamin E, magnesium, boron, folic acid, zinc and phytochemicals like lignans, phytoestrogens and phenolic acids are all present in these great unrefined whole grains.

  30. Know Your Grains • Whole grains are defined as grains that contain the completed kernel-all three parts: 1. Bran is packed with fiber B vitamins 2. Endosperm contains carbohydrates and proteins 3. Germ is rich with B vitamins, minerals, and phytochemicals (substances in plants) • Refined grains have most of the bran and germ removed

  31. Know Your Grains

  32. Test Yourself 1. Which breads are usually all or mostly whole grain? • whole wheat (b) multi-grain (c) rye (d) pumpernickel 2. Which grains are whole? • bulgur (b) quinoa (c) couscous (d) oatmeal 3. What’s the most nutritious grain? • corn meal (b) millet (c) quinoa (d) oatmeal

  33. Answer: a • Whole wheat refers to the whole complete wheat shaft • In theory, multi-grain, rye and pumpernickel breads can be whole grain - you must check the labels though. If it lists one of these whole grains first, it usually is • If it says made with enriched or wheat flour, multi-grain flours or pumpernickel flours, then it is mostly refined grain

  34. 2. Answers: b and d • Quinoa and oatmeal are whole grains • Bulgur and couscous may also be but check for the whole grain wording on the label. • Quinoa

  35. 3. Answer: c • Quinoa has been a staple food to the natives of the South American Andes since 3000 BC • Quinoa has the highest protein content of any grain • It is one of the grains highest in calcium, iron, copper, magnesium, Vitamin E, phosphorus and B vitamins. • Quinoa is great for a vegetarian diet because of lysine and methonine, two amino acids which are generously supplied by this grain and notably low in vegetarian diets • Quinoa has a delicious nutty flavor and crunchy texture

  36. Top 5 Healthiest Grains 1. Quinoa (pronounced keen-wah) 2. Buckwheat Groats (when roasted called Kasha) 3. Barley 4. Millet (it is considered to be one of the least allergenic and most easily digestible grains) 5. Bulgur • Other recognized whole grains are oats and oatmeal, brown rice, wild rice, corn meal, wheat berries and whole wheat macaroni and spaghetti.

  37. What to Look for on the Food Label • Choose foods that name one of the following whole-grain ingredients first on the label’s ingredient list: • brown rice, whole oats, bulgur, whole rye, graham flour, whole wheat, oatmeal, wild rice, whole-grain corn • Foods labeled with the words multi-grain, stone-ground, 100% wheat, “cracked wheat”, “seven-grain”, or bran are usually not whole-grain products.

  38. What to Look for on the Food Label • Color is not an indication of a whole grain. Bread can be brown because of molasses or other added ingredients. • Read the ingredient list to see if it is a whole grain.

  39. Tips to Help You Eat Whole Grains • Try brown rice or whole-wheat pasta • Try brown rice stuffing in baked green peppers or tomatoes and whole-wheat macaroni in macaroni and cheese • Use whole grains in mixed dishes, such as barley in vegetable soup or stews and bulgur wheat in casserole or stir-fries • Create a whole grain pilaf with a mixture of barley, wild rice, brown rice, broth and spices. For a special touch, stir in toasted nuts or chopped dried fruit.

  40. Tips to Help You Eat Whole Grains • Substitute whole wheat or oat flour for up to half of the flour in pancake, waffle, muffin or other flour-based recipes. They may need a bit more leavening. • Use whole-grain bread or cracker crumbs in meatloaf. • Try rolled oats or a crushed, unsweetened whole grain cereal as breading for baked chicken, fish, veal cutlets, or eggplant parmesan.

  41. Tips to Help You Eat Whole Grains • Try an unsweetened, whole grain ready-to-eat cereal as croutons in salad or in place of crackers with soup. • Freeze leftover cooked brown rice, bulgur, or barley. Heat and serve it later as a quick side dish.

  42. What is High Fructose Corn Syrup? • Experts are finding that high-fructose corn syrup (HFCS) is making us fat • High-fructose corn syrup is a highly refined, artificial product • It is created through an intricate process that transforms cornstarch into a thick, clear liquid • Experts agree that high-fructose corn syrup is worse than sugar

  43. The Dangers of High Fructose Corn Syrup • This manufactured fructose is sweeter than sugar in an unhealthy way, and is digested differently in a bad way. • Research has shown that high-fructose corn syrup goes directly to the liver, releasing enzymes that instruct the body to then store fat

  44. The Dangers of High Fructose Corn Syrup • This fake fructose may slow fat burning and cause weight gain • Other research indicates that it does not stimulate insulin production, which usually creates a sense of being full. People may eat more than they should. • Increases LDL's (the bad lipoprotein) leading to increased risk of heart disease

  45. The Dangers of High Fructose Corn Syrup • Alters magnesium balance leading to increased risk of osteoporosis. • Increased risk of Type 2 Diabetes • It has no enzymes or vitamins thus robbing the body of precious micro-nutrients. • It interacts with birth control pills and can elevate insulin levels in women on the pill. • Accelerates aging

  46. The Dangers of High Fructose Corn Syrup • It inhibits copper metabolism leading to a deficiency of copper, which can cause increased bone fragility, anemia, ischemic heart disease and defective connective tissue formation among others.

  47. Where Do You Find High Fructose Corn Syrup? • High-fructose corn syrup is highly valued by food manufacturers • It's easy to transport in tanker trucks • It isn't susceptible to freezer burn, as is sugar • It has a long shelf life and keeps foods from becoming dry • It gives bread and baked products a wonderful color

  48. Where Do You Find High Fructose Corn Syrup? • It's also cheaper than white sugar, partly because of generous federal subsidies and trade policies that encourage farmers to grow more corn. • Fast food chains add it to their products because it is cheaper. • It is in the sauces, in the condiments, in the breadings, in the buns and in soft-drinks • It is the commercially preferred artificial sweetener. • What's worse than sugar? Now you know.

  49. Glycemic Food Index • The Glycemic Index (GI) relates to the way your body’s sugar levels respond to certain foods. • Foods are given a rating from 0 –100 on the glycemic index with glucose in the highest position. • High Glycemic Index foods (white bread, white rice, potatoes) will increase the body’s sugar levels rapidly whereas low glycemic index foods (lentils, chickpeas, navy beans) will increase the body’s sugar levels slowly.