Ch 7 - Vitamins

vitamins

organic compounds vital to life and indispensable to body function, but only needed in small amounts

precursors, provitamins

compounds that can be converted into active vitamins

properties of vitamins

essential micronutrient, organic, non-caloric, most help regulate rxns as coenzymes

2 classes of vitamins

fat soluble and water soluble

the fat soluble vitamins

vitamins A, D, E, and K

fat soluble vitamins are absorbed with ____ and transported via ___

fat, lipoproteins

are excess fat soluble vitamins excreted in urine?

no

overdoses of fat soluble vitamins can cause this

toxicity

length of time leading to deficiency of fat soluble vitamins

longer

these vitamins are water soluble

B complex vitamins and Vitamin C

absorbed ____ into the bloodstream (except B12 which needs ____)

directly, intrinsic factor

are water soluble vitamins stored in the body?

not really

water soluble vitamins are usually not toxic unless ___

high doses are consumed

excess water soluble vitamins are _____

excreted in urine

frequency of water soluble vitamins needed in order to prevent deficiency

regular supply

characteristics of fat soluble vitamins

require bile for absorption, stored in fatty tissues, deficiencies caused by malabsorption disesases

retinoids

(retinol) preformed vitamin A, antioxidant functions, can be toxic

carotenoids

(beta carotene) vitamin A precursor from plant products that is converted if necessary, antioxidant functions

functions of Vitamin A

visual abilities, cell growth & reproduction, immunity, epithelial tissue

Vitamin A deficiency

often seen in developing countries; blindness, infections, growth defects, exhaustion, death

Vitamin A toxicity

skin rashes, hair loss, hemorrhages, bone abnormalities & fractures, yellow skin, birth defects, liver failure, death

food sources of Vitamin A

milk, carrots, sweet potatoes, spinach and green leafy vegetables, liver, apricots

vitamin received from sun exposure

Vitamin D

functions of Vitamin D

maintains calcium levels, bone mineralization and regrowth; works in brain, heart, skin, reproductive organs

Rickets

vitamin D deficiency in children; bones are too weak to support the body, bowing out of legs, knock knees, beaded ribs

Osteomalacia

vitamin D deficiency in adults, softening of bones, leads to fractures

vitamin D toxicity

most potentially toxic; extra calcium deposits where it doesn't belong (soft tissue), excessive thirst, headache, nausea

food sources of vitamin D

milk, salmon, shrimp, enriched foods

tocopherol

vitamin E

functions of vitamin E

works as an antioxidant to stop free radicals from destroying cell components, helps nerve development and immune system

vitamin E deficiency

very rare; erythrocyte hemolysis in preemies or fat malabsorption; impaired vision/speech, loss of muscle coordination

vitamin E toxicity

interferes with vitamin K and anticoagulation

food sources of vitamin E

safflower oil, canola oil, sunflower seeds, wheat germ

functions of vitamin K

synthesis of blood clotting proteins (prothrombin) and bone proteins

vitamin K deficiency

due to long term antibiotic use or in newborn babies; hemorrhage, abnormal bone formation

vitamin K toxicity

sometimes seen in infants or pregnant women; opposes effects of anti-clotting meds, jaundice

sources of vitamin K

50% comes from the intestinal tract; cabbage, cauliflower, spinach, canola oil, soybeans, lettuce

B - complex vitamins

Thiamin, Riboflavin, Niacin, Folate, B12, B6 (Pyridoxine), Biotin, Panothenic Acid

reason to take extra water soluble vitamins

NONE, excreted in urine anyway

functions of vitamin C

produces and maintains collagen, enhances immune response, thyroxine regulation/production, helps produce carnitene (transports fatty acid), iron absorption

are vitamin C claims accurate?

mostly not

Scurvy

vitamin C deficiency, often seen in elderly, smokers, alcoholics, drug addicts, infants only fed cow's milk

symptoms of vitamin C deficiency

***

vitamin C toxicity

altered insulin response to carbs, nausea, abdominal cramps, diarrhea, extreme gas, drug rxns

food sources of vitamin C

fresh fruits and veggies; orange juice, red and green peppers, broccoli, brussel sprouts, citrus fruits, sweet potato, strawberries

B vitamins are

coenzymes