Vitamins

Vitamin A

Function: vision, immune function, bone/body growth, reproduction, healthy body linings, skin

Sources: (preformed active) liver, enriched milk; (precursor - beta carotene) bright orange and dark green fruits and vegetables

Deficiency: night blindness (early), blindness (severe), dry skin, eroded body linings, decreased immune function

Toxicity: hair loss, stunted growth, liver failure, weak bones (from supplements), yellow skin (from beta carotene)

***Different forms:

• Retinol: transportation and storage, what we consume

• Retinal: vision

• Retinoic acid: growth, gene regulation

DRI is based on RAE

Vitamin D

Function: promotes bone mineralization (gets calcium and phosphate), immune function

Sources: sunlight (UVB), salmon, mackerel, sardines, tuna, fortified milk, egg yolks

Deficiency: rickets (children) and osteomalacia (adults)

Toxicity: most potentially toxic (not possible from sun exposure), can be deadly

Vitamin E

Function: protects cell membranes, immune system, fat-soluble antioxidant

Sources: vegetable oils, fruits, vegetables

Deficiency: rare, inadequate intake is common, based on absorption rather than consumption

Toxicity: rare, large doses may interfere with coagulants

DRI is based on alpha tocopherol (smokers may have higher needs)

Vitamin K

Function: blood clotting, bone formation

Sources: made by intestinal bacteria (not enough), dark green leafy vegetables

Deficiency: rare, injection at birth

Toxicity: not common from food sources

Thiamin, Riboflavin, Niacin

Function: energy metabolism

Sources: whole grain bread/cereals, enriched bread/cereals

• Riboflavin: milk

• Niacin: meat, fish, poultry

Thiamin Deficiency: beriberi (loss of sensation in hands and feet)

Niacin Deficiency: pellagra (rough skin)

Niacin Toxicity: UL is based on synthetic sources, large doses can cause painful tingling

Biotin and Pantothenic acid

Function: energy metabolism

• Biotin: coenzyme in digestion

• Pantothenic acid: stimulates growth

Deficiency and Toxicity: none, well balanced diet is enough

Vitamin B6

Function: amino acid synthesis, hemoglobin synthesis, regulation of blood glucose

Sources: meats, fish, poultry, potatoes, bananas

Deficiency: general symptoms (weakness, immune response)

Toxicity: supplements can be dangerous, stored in muscle, can cause reversible neuropathy

Vitamin B12

Function: enables folate to get into cells, helps maintain sheath around nerve cells

Sources: animal products (eggs, milk, cheese, meats), fortified products for vegans

Deficiency: results from poor absorption rather than intake, pernicious anemia, paralysis of nerves and muscles

Toxicity: no reported symptoms

Folate

Function: synthesizes DNA for cell division in tissues, antacids and aspirin interfere with the use of folate

Sources: green leafy vegetables, breads and cereals (now fortified with folic acid)

Deficiency: anemia, impaired cell division, neural tube defect at birth

Toxicity: can mask B12 deficiency which causes nerve damage, UL for supplements and fortified foods only

RDA: essential nutrient for women of child bearing age (measured in DFE)

Vitamin C

Function: produces and maintains collagen, immune response (doesn’t prevent colds), iron absorption, antioxidant

Sources: citrus fruits and juices, sweet potatoes, strawberries, kiwi, broccoli, tomatoes, peppers

Deficiency: bleeding gums and early bruises (early) scurvy (when >10mg/day)

Toxicity: large doses in pill form (people w/ blood thinners, kidney stones, gout) can cause nausea, cramps, and diarrhea