Nutrition Ch.10

Bioavailability

Rate and extent to which a nutrient is absorbed and used.

What does bioavailability depend on?

Efficiency of digestion/time of transmit through GI Tract

Previous nutrient intake and nutrition status

Other foods that may inhibit or enhance absorption

Source - whether natural or synthetic

Precursor

Form they are in food that is inactive

Once consumed it is converted to it’s active form

Fat Soluble Vitamins

Hydrophobic

found in fats and oils

absorbed into lymph then blood

require transport proteins

stored in cells associated with fat

less readily excreted

likely to reach toxic levels when consumed from supplements

needed in periodic doses

Water Soluble Vitamins

Hydrophilic

Absorbed into blood

travel freely

circulate freely in water-filled parts of body

Kidneys detect and excrete excess in urine

Possible to reach toxic levels when consumed from supplements

Needed in frequent does

Primary function in B Vitamins

Act as coenzymes in energy production

Function of a Coenzyme

To help compounds A, B, and CD respond to their enzymes

Beriberi

Deficiency disease of Thiamin

Wet, with edema

Dry, with muscle wasting

Richest food sources of Thiamin

PORK, other meats and grains

Best cooking method for food sources of Thiamin

Microwave

Function of the coenzyme form of Riboflavin

Carries hydrogens to the Electron Transport Chain

Deficiency disease of Riboflavin

Ariboflavinosis

Deficiency symptoms of riboflavin

Inflamed eyelids and sensitivity to light

Reddening of cornea

Cracks and redness at corners of mouth

Painful, smooth, purplish tongue

Inflammation characterized by skin lesions covered with greasy scales

Best food source of Riboflavin

Grains and Milk

What destroys Riboflavin?

UV Light

Niacin and Tryptophan

Tryptophan is the precursor of Niacin

Pellagra

Deficiency disease of Niacin

Deficiency symptoms of Niacin

4 D’s (Dermantis, Diarrhea, Dementia, and Death)

Inflamed, swollen, smooth, bright red tongue

Bilateral symmetrical rash on areas exposed to sunlight

Niacin flush

Toxicity symptoms of Niacin (painful flush, hives, and rash)

Protein found in what food inhibits absorption of Biotin

Raw egg whites

Vitamin synthesized by intestinal bacteria

Biotin

Vitamin that is part of Coenzyme A

Pantothenic Acid

Vitamin thought to combat PMS

Vitamin B6

Vitamin that reduces risk of neural tube defects

Folate

Most common neural tube defect

Spina Bifida (sac forms on spine)

Function shared by Vitamin B12 and Folate

Removing the methyl group in activation (Deficiency in either results in anemia)

Vitamin bound to glutamic acid molecules in food

Folate

Bioavailability of folate

Dietary: 50%

Supplemental: 100%

Deficiency symptoms of folate

Anemia (megaloblastic anemia)

Smooth, red tongue

Intrinsic Factor

What Vitamin B12 must bind with in small intestine to be absorbed

Likely reason for B12 deficiency

Atrophic Gastritis (inflammation of the stomach, common in older people)

Deficiency symptoms of B12

Anemia

Degeneration of peripheral nerves (leads to paralysis)

Groups at risk for B12 deficiency

Vegetarians since it mainly comes from animal sources

Pernicious anemia

B12 deficiency caused by Atrophic gastritis and lack of intrinsic factor

Main functions of Vitamin C (antioxidant)

Collagen synthesis (Strengthens blood vessel walls, forms scar tissue)

Thyroxin Synthesis (metabolism)

Strengthens resistance to infection

Vitamin C deficiency signs and symptoms

Atherosclerotic plaques

Pinpoint hemorrhages, bone fragility, joint pain

Bleeding gums, loosened teeth

Foods rich in Vitamin C

Citrus fruits, cabbage type and dark green veggies, cantaloupe, strawberries, etc.

Alt name for Thiamin

Vitamin B1

Alt name for Riboflavin

Vitamin B2

Alt names of Niacin

Nicotinic acid

Nicotinamide

Niacinamide

Alt name for Vitamin B6

Pyridoxine

Alt names for Folate

Folic acid

Folacin

Pteroylglutamic acid (PGA)

Alt name for Vitamin B12

Cobalamin

Alt name for Vitamin C

Ascorbic acid