Nutrient

RDA

UL*

Experimental high dose**

Potential toxic effects

Main function

Best food sources

Vitamin A

Men: 3,000 IU
Women: 2,300 IU

10,000 IU

3,000-10,000 IU

Liver toxicity, dry rough skin and cracked lips, irritability, headache, birth defects

Healthy immune barriers and epithelial tissue, growth, reproduction, bone and red blood cell formation, vision

Foods high in beta carotene, fortified foods, liver

Beta carotene (as mixed carotenoids)

N.D.

N.D.

5,000-25,000 IU

Possibly increased lung cancer in smokers, harmless orange skin colour

Antioxidant, source of vitamin A, immune booster, possible cancer prevention, vision

Orange, yellow, red and green vegetables and fruits

Vitamin D

9-50 years: 200 IU
51-70 years: 400 IU
> 70 years: 600 IU
Osteopenia or osteoporosis: 1,000 IU

2,000 IU

1,000 IU

Heart/liver/kidney toxicity, hypercalcemia (excess calcium in the blood)

Calcium metabolism, bone mineralization, possible cancer prevention

Fortified milk, fatty fish

Vitamin E

22 IU

1,500 IU

200 IU

Possible increase in heart disease, excess bleeding

Antioxidant, anticoagulant, protection from heart disease, possible cancer prevention

Wheat germ, vegetable oils, nuts

Vitamin K

M: 120 mcg
W: 90 mcg

N.D.

N.D.

Interaction with blood thinners

Bone mineralization, blood clotting

Green leafy vegetables

Vitamin C

M: 90 mg
W: 75 mg
smokers add 35 mg

2,000 mg

500-2,000 mg

Pro-oxidant, excess iron absorption, diarrhea

Antioxidant, immunity, antiviral in test-tubes, cancer prevention, increases iron absorption

Fruits and vegetables, especially peppers and citrus fruits

Thiamine (B₁)

M: 1.2 mg
W: 0.9 mg

N.D.

30-100 mg

Very high doses may promote tumour growth

Energy metabolism, mood, nervous system

Whole grains, brown rice, fortified foods, legumes, pork, oysters

Riboflavin (B₂)

M: 1.3 mg
W: 1.1 mg

N.D.

30-100 mg

N.D.

Energy metabolism, antioxidant, possible migraine prevention

Dairy products, leafy greens, oysters

Niacin (nicotinic acid)

M: 16 mg
W: 14 mg

35 mg

500-1,000 mg

Itching, skin flushing,
Liver toxicity, insulin resistance

Energy metabolism, lowers LDL cholesterol and triglycerides, raises HDL cholesterol

Poultry, red meat, fish, legumes, peanut butter, nuts

Vitamin B₆

M: 1.3-1.7 mg
W: 1.3-1.5 mg

100 mg

100 mg

Nerve damage (neuropathy)

Protein metabolism, immunity, neurotransmitter synthesis (e.g. serotonin and dopamine), treats peripheral neuropathy and PMS

Meat, fish, poultry, eggs, potatoes, fortified cereals, peanuts, soybeans

Folate

0.4 mg

1 mg

0.4 -1.0 mg

High dose can mask B₁₂ deficiency leading to nerve damage

Cell division, prevents neural tube defects and perhaps other birth defects, lowers homocysteine, possible cancer prevention

Leafy greens, legumes, oranges, broccoli, cauliflower

Vitamin B₁₂ (cobalamin)

2.4 mcg

N.D.

1,000 mcg weekly or monthly for deficiency

Rare cases of eye damage

Cell division, amino acid metabolism, nervous system, mental function

Fish, shellfish, meat, fortified soy and rice milk, fermented soy products

Calcium

1,000-1,200 mg

2,500 mg (from food and supplements)

1,000-1,500 mg

Calcium deposits in soft tissues

Bone mineralization, muscle contraction

Dairy products, fortified soy and rice milk, fish bones

Magnesium

M: 400 mg
W: 320 mg

350 mg

350 mg

Diarrhea, decreased calcium absorption

Bone mineralization, active in more than 300 chemical reactions in the body

Whole grains, nuts, green vegetables, legumes

Iron

M: 8 mg
W: 18 mg

45 mg

Use only to treat iron-deficiency anemia

Iron overload disorders, heart disease, liver cirrhosis

Makes hemoglobin which carries oxygen, makes energy in the mitochondria

Meat, legumes, tofu, leafy greens, breakfast cereals

Zinc

M: 11 mg
W: 8 mg

40 mg

40 mg

Immune suppression, nausea, metallic taste, copper deficiency

Growth, immunity, wound healing, taste, sperm production, antioxidant, prostate health

Oysters, meat, poultry, fish

Selenium

55 mcg

400 mcg

100-400 mcg

Brittle hair and nails, irritability, garlic breath, fatigue, nausea

Antioxidant, immunity, possible cancer prevention, viral infections

Whole grains from selenium-rich soils, poultry, meat, dairy

RDA: recommended daily allowance (from all sources); UL: upper tolerable limit (from supplements only); N.D.: not determined; IU: international unit; mg: milligram; mcg: microgram
* Caution should be exercised when taking doses above the UL.
** There is little to no evidence of efficacy for these doses. Discuss your options with your physician and dietitian.