1. Carbohydrates

2. Functions of Carbohydrates
Provides energy
4 calories per gram
Storage form called glycogen
Protein sparing action
Normal fat metabolism
Fat oxidization in cells produces ketones
Ketones- acids that accumulate in blood and urine
Ketoacidosis- acid-base balance upset, caused from starvation or low carb diets; can lead to coma or death
Provides fiber
Creates soft bulky stool that moves quickly through the large intestine

3. Food Sources Plant foods Good source of vitamins and minerals
Cereal grains, vegetables, fruits, sugars
Good source of vitamins and minerals
Enriched- B vitamins such as thiamine, riboflavin, and niacin added back after processing; also iron
Fortified- nutrient added that was never part of the grain, such as folic acid
Vegetables
Starch- potatoes, beets, peas, lima beans, corn
Fiber- green leafy
Fruits- fructose
Sugars- table sugar, syrup, honey

4. Classification of Carbohydrates
Monosaccharides
Disaccharides
Polysaccharides

5. Monosaccharides
Glucose- also called dextrose, all other forms converted to this
Corn syrup, some fruits and vegetables
Only source of fuel for central nervous system, red blood cells, and the brain
Fructose- also called levulose
Found with glucose in many fruits and honey
Sweetest of all monosaccs
Galactose- product of the digestion of milk

6. Disaccharides Sucrose- composed of glucose and fructose
Granulated, powdered, brown, and molasses
Sweetest, and least expensive
Maltose- produced by digestion of starch, created by fermentation process of alcohol
Infant formulas, malt beverages, beer
Less sweet than glucose or sucrose
Lactose- milk sugar
Helps body absorb calcium
Less sweet than all other sugars

7. Lactose Intolerance Body unable to digest lactose
Insufficient amounts of lactase- enzyme required for digestion of lactose
Bloating, abdominal cramps, diarrhea
Making cheese:
Milk separates into curds (solid) and whey (liquid)
Lactose in whey
No specific test for lactose intolerance

8. Polysaccharides
Starch- longer to digest; supply energy over a period of time
Grains, vegetables, dried beans and peas
Parts of the grain:
Glycogen- storage form of glucose in the body
½ day’s supply of energy is stored as glycogen
Dietary Fiber- called roughage, cannot be broken down by digestive enzymes
Soluble: partially dissolves in water
Insoluble: does not dissolve in water
Cellulose: primary source of dietary fiber
Skins of fruits, leaves and stems of vegetables, legumes

9. Fiber Helps lower blood glucose levels
Moves waste materials through colon faster, reducing exposure time to carcinogens
Helps prevent constipation, hemorrhoids, and diverticulitis
Recommended intake: g/day
Eating too much fiber in a short period of time can produce discomfort, gas, and diarrhea
Choose natural sources rather than supplements

10. Digestion and Absorption
Monosaccharides absorbed from the intestine directly into the bloodstream, carried to the liver, changes to glucose, then carried to cells
Disaccharides are converted to glucose
Polysaccharides: After cellulose wall is broken down, starch is changed to dextrin, then maltose, then glucose
Digestion begins in the mouth where the enzyme salivary amylase changes starch to dextrin.
Changes to simple sugars in the small intestine then absorbed by the blood

11. Metabolism and Elimination
Glycogen is formed when the cells cannot hold anymore glucose
Stored in the liver and muscles
Glucose converted to fat when the body cannot immediately use or store it
Glucose metabolism is controlled by insulin
When secretion of insulin is impaired or absent, blood glucose levels become high: Hyperglycemia
Hypoglycemia: blood glucose levels are low
Hunger is mild form and can result in fatigue, shaking, sweating, headache

12. Dietary Requirements
Half of energy should come from carbohydrates, mostly complex carbs
About 250 g/day
Weight loss and fatigue can result from eating few carbs
Surplus of carbs result in weight gain, spoiled appetite, and tooth decay

13. Fats

14. Functions of Fat Energy Cushion to protect organs Insulation
Transports vitamins
9 calories per gram
30% of daily calories

15. Sources
Animal foods
Cooking oils (from plants)
Nuts
avocados

16. Classification of Fats
Saturated- animal foods
Monounsaturated- olive oil, peanut oil, nuts, avocados
Polyunsaturated- soybeans

17. Cholesterol Found in animal foods Can lead to heart attacks
LDL- bad cholesterol
HDL- carry cholesterol away from the heart and back to the liver

18. Protein

19. Function of Proteins Energy Build and repair body tissues
Help maintain fluid and electrolyte balance
4 calories per gram
10% of daily calories

20. Sources Complete proteins- animal foods
Incomplete proteins- plant foods
Soybeans are complete proteins
Complementing proteins- combination of incomplete and complete proteins