Carbohydrates

1. Carbohydrates Unit 2,Chapter 4 Stephen T. Kabrhel, M.S., A.T.C.

2. General Information • Carbohydrates - (CHO) - A compound that breaks down into glucose. • Glucose - Form of sugar that the body uses to make energy. • CHO made up of carbon, hydrogen, oxygen in varying structures. They are classified as either simple or complex. • SimpleCarbohydrates - Monosaccharides and Disaccharides • ComplexCarbohydrates - Polysaccharides

3. Types of Carbohydrates Monosaccharides Disaccharides Polysaccharides

4. Types of CHO - Monosaccharides • Monosaccharides - are knows as simple sugars. They have the form C6H12O6. Each has a different arrangement of this. • Glucose - blood sugar. There is always a glucose in a disaccharide. The storage form of glucose is glycogen. It fuels most of the body’s cells, and is the exclusive energy supply to the brain, nervous cells, and developing blood cells. • Fructose - occurs naturally in fruit and honey. Used commonly as sweeteners. • Galactose - found in milk, usually attached to glucose, not free.

5. Types of CHO - Disaccharides • Disaccharides - two monosaccharides put together. Glucose is always one of the mono. • Maltose - 2 glucose together. Found in alcohol fermentation. Rarely found in food. • Sucrose - glucose and fructose - found in fruits, vegetables, and grains (which makes them sweet). It is what is refined to make table sugar. • Lactose - Glucose and Galactose - found in milk.

6. Types of CHO - Polysaccharides • Polysaccharides - multiple monosaccharides, primarily glucose. • Glycogen - storage form of glucose found in animals. • Starches - storage form of glucose found in plants (wheat, rice, potatoes, peas, beans). They are broken down in the stomach. • Fibers - structure of plants (not to be confused with starch). They cannot be broken down in stomach.

7. Fiber Classification by Chemical Property • Cellulose - makes plant cell walls - found in veggies, fruits, legumes. Glucose molecules in chains. • Hemecellulose - main ingredient of cereal fibers. • Pectins - backbone of carbohydrates in the form of chains of monosaccharides. Found in fruits and veggies, used as thickener in jelly, salad dressings, etc. • Gums and Mucilages - monosaccharides found as aid to plant injury. Used as additives and stabilizers. • Lignin - 3-dimensional structure. Found in seeds, etc. It can’t be digested so it is rarely seen unnaturally.

8. Fiber Classification by Solubility • Insoluble fiber - doesn’t dissolve in water • Wheat bran, whole-grain breads, vegetables • Will accelerate GI transit, increase fecal weight • See Table 4-1.

9. Fiber Classification by Solubility • Soluble fiber - dissolves in water. • Fruits, oats, barley, legumes. • Delay’s GI transit, delays glucose absorption, lower blood cholesterol. • See Table 4-1

10. Digestion, Absorption and Transportation

11. CHO Digestion and Absorption • We eat CHO to get calories from glucose. • Mouth - chewing and presence of enzyme amylase in saliva starts to break down starches. Plants (starch) breakdown into polysaccharides and maltose. Fiber is not broken down. • Stomach - acid as well as enzymes mix with the Bolus. Their job is to inactivate amylase as well as break down some starched. However, the digestion is minimal in the stomach. Fiber will stay longer in stomach, creating full feeling (satiety).

12. CHO Digestion and Absorption • Small intestines - it is here where polysaccharides are broken down. It contains the necessary enzymes (Pancreatic amylase), resulting in disaccharides and glucose chains. • Outside Intestines - Sucrase, maltase, lactase will breakdown these disaccharides. • Maltase breaks maltose into 2 glucose. • Sucrase breaks sucrose into 1 glucose, 1 fructose. • Lactase breaks lactose into 1 glucose, 1 Galactose. • Glucose moves into blood stream. Fructose and Galactose are transported to and then converted into glucose in liver.

13. CHO Digestion and Absorption Cont. *IT takes 1-4 hours to digest all starches. • Large Intestines - Some starches (resistant starches) and fiber remain and are not broken down. In L.I., they attract water, which softens stool and allows for easy passage. • Fermentation (breakdown of starches and fiber without O2) also occurs, producing water, gas and fatty acids needed for energy.

14. CHO Digestion and Absorption Cont. • Blood • Glucose and Galactose move to blood from intestine by way of active transport. • Fructose - moves through intestine by way of facilitated diffusion, which is slower than active transport. • Galactose and fructose are deposited at the liver where they are further broken down into glucose. • Blood takes in glucose in from liver.

15. Lactose Intolerance • Lactase is an enzyme that breaks down lactose. Lactase activity is high at birth, decreases over time. Some people do not have lactase active at birth. If lactose isn’t broken down, it stays in the intestines, attracting water, causing bloating, discomfort, and diarrhea. • Dietary changes can help, altering dairy including eating lactose free diary.

16. Carbohydrate Metabolism

17. Carbohydrate Metabolism • Glycogen – Is the storage form of glucose • The liver stores about 1/3 of the bodies supply. • Muscle stores the rest. • Storage can last for a few hours. • 4kcal /g • Glucose can be made from protein, but not from fat. • Called Gluconeogenesis. • Protein sparing is when we intake enough carbs so that we don’t have to rely on protein to make glucose. • CNS only uses glucose for energy. • Extra glucose that is not stored will end up as fat. • Insulin, Glucagon, and epinephrine all are hormones that regulate the movement of glucose into and out of storage.

18. Health Affects of Sugar • This refers to simple sugars. • They can be either naturally found or artificially made. • Moderate amounts are fine. • Large amounts are not healthy • Found usually in form of “empty-calorie” foods. I.e. no nutrients value. • These sugars will contribute to tooth decay. • Bacteria that break down the sugar in the mouth produce acids, which dissolve tooth enamel. • Sticky foods stay longer which exacerbate the problem. • High sugar foods tend to also be high fat, which leads to obesity.

19. Health Affects of Sugar • High level of sugars will change lipid amounts to increase risk of heart disease. • There is no scientific proof that sugar leads to hyperactivity. • Recommend that we eat 10% or less of total daily kcal.

20. Health Affects of Starches and Fiber • Weight Control • High complex carbohydrates – Foods that have these tend to have less fat. • Promote the glycemic affect • Fiber will delay hunger, provide satiety. • Nutritious. • Heart Disease • Recommended amounts will decrease the chance of heart disease and stroke. • There will an associated decrease in animal fat and cholesterol intake that associates with an increase in starch and fat intake.

21. Health Affects of Starches and Fiber • Heart Disease cont. • Diets will be higher in fiber and vegetable protein. • Soluble fibers bind to bile, which in turn decreases cholesterol. • Cancer • Foods that contain Vitamin C and Vitamin E, green and yellow veggies, citrus fruits will contain antioxidants to fight cancers. • High fiber diets will decrease the risk of colon cancer by speeding up processing and transport in large intestines. • Diabetes • Diets high in starches and fiber. Promote healthier walls in artery. • Slows digestion, maintaining glucose levels.

22. Health Affects of Starches and Fiber • G.I. Health • Fibers enhance Large Intestine Function. • They also block “bad partials/foods”. • They attract water in LI for faster passage. • Insoluble fibers – such as Bran, fruits and veggies increase the fecal weight, easing passage. • Promotes strong, relaxed muscles in lower GI, preventing hemorrhoids.

23. Health Affects of Starches and Fiber • Harmful Affects of High Fiber diets • Many not receive enough KCAL, leading to malnourishment. • Can get temporary gas, diarrhea, GI obstruction, if you switch fast. • Too much insoluble fiber increase transit speed, preventing nutrients from being totally absorbed. • Recommendations • 55-60% of carbohydrates in diet • Fiber – sources are whole grains, fruits and legumes • 25g/2000kcal diet or 11.5g/1000kcal