Sources of Polysaccharides

Sources of Polysaccharides:

1. starch potatoes, corn, yams, noodles, beans

2. glycogen glucose stored in liver, muscles

3. cellulose wheat bran, whole grain, cereals, fruits, green leafy vegetables

4. hemicellulose whole grains

Digestion & Absorption of Monosaccharides

1. simple sugars directly absorbed into bloodstream

2. carried to liver fructose & galactose changed to glucose & this is carried to cells

Digestion and Absorption of disaccharides

1. enzymes sucrase, maltase, & lactase change sucrose, maltose & lactose to glucose

2. simple sugars absorbed directly into bloodstream

3. glucose carried to cells

Digestion and Absorption of Polysaccharides

1. more complex, digestibility varies

2. cellulose wall broken down, starch Δ'd to dextrin →maltose →glucose

3. starch digestion begins in the mouth (salivary amylase changes starch to dextrin)

Metabolism

1. Islets of Langerhans pancreas secretes insulin (hormone that controls glucose metabolism)

2. insulin is the hormone

3. impaired or absent insulin secretion (glucose ↑ = hyperglycemia)

4. low blood glucose level (not eating, insulin ↑ = hypoglycemia)

Dietary Requirements Food and Nutrition Board of the National Research Council recommends:

1. need half of energy requirements come from CHO's preferably (complex) polysaccharides

2. weight loss & fatigue can result from diet ↓ in CHO's

3. severe deficiency in ketosis

4. surplus becomes fat

5. excessive CHO intake can lead to obesity, dental caries, digestive disturbances

Fat Facts:

1. fats belong to a group of organic compounds called lipids

2. greasy substances insoluble in water

3. each gram of fat contains 9 calories

4. composed of carbon, hydrogen, and oxygen (has ↓ O₂ than CHO's)

Functions of Fats

1. provide energy

2. carry fat-soluble vits. A, D, E, & K

3. supply essential fatty acids

4. protect & support of organs & bones

5. insulate from cold

6. provide satiety after meal

Food Sources

1. Animal

a. fatty meats, fish (shrimp)

b. dairy products

c. whole milk

d. egg yolk

2. Plant

a. vegetable oil & margarine

b. nuts & olives

c. chocolate

d. avocado

Visible fats fats in foods that are purchased & used as fats butter, margarine, lard, cooking oil

Invisible fats fats that are not immediately noticeable egg yolks, cheese, cream, & salad dressing

Classifications

A. Triglycerides

1. most lipids in the body 95%

2. composed of three fatty acids attached to glycerol framework

B. Phospholipids similar to triglycerides, but have 2 fatty acids & peptide group

C. Sterols lipid = cholesterol