Vitamins

Definition

Vitamins are a group of substances that are needed for normal cell function, growth, and development.

There are 13 essential vitamins. This means that these vitamins are required for the body to work properly. They are:

Vitamins are grouped into two categories:

Function

Each of the vitamins listed below has an important job in the body. A vitamin deficiency occurs when you do not get enough of a certain vitamin. Vitamin deficiency can cause health problems.

Not eating enough fruits, vegetables, beans, lentils, whole grains and fortified dairy foods may increase your risk for health problems, including heart disease, cancer, and poor bone health (osteoporosis).

Food Sources

FAT-SOLUBLE VITAMINS

Vitamin A:

Vitamin D:

Vitamin E:

Vitamin K:

WATER-SOLUBLE VITAMINS

Biotin:

Folate:

Niacin (vitamin B3):

Pantothenic acid:

Thiamine (vitamin B1):

Pyroxidine (vitamin B6):

Vitamin B12:

NOTE: Animal sources of vitamin B12 are absorbed much better by the body than plant sources

Vitamin C (ascorbic acid):

Side Effects

Many people think that if some is good, a lot is better. This is not always the case. High doses of certain vitamins can be toxic. Ask your health care provider what is best for you.

Recommendations

The Recommended Dietary Allowances (RDAs) for vitamins reflect how much of each vitamin most people should get each day.

The best way to get all the daily vitamins you need is to eat a balanced diet that contains a wide variety of fruits, vegetables, fortified dairy foods, legumes (dried beans), lentils, and whole grains.

Dietary supplements are another way to get the vitamins you need if the food you eat is not supplying enough vitamins. Supplements can be helpful during pregnancy and for special medical problems.

If you take supplements, DO NOT take more than 100% of the RDA. Be very careful about taking large amounts of fat-soluble vitamin supplements. These include vitamins A, D, E, and K. These vitamins are stored in fat cells, and they can build up in your body and may cause harmful effects.

References

Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academy Press. Washington, DC, 1998. PMID: 23193625 www.ncbi.nlm.nih.gov/pubmed/23193625.

Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenium, Nickel, Silicon, Vanadium, and Zinc. National Academy Press. Washington, DC, 2001. PMID: 25057538 www.ncbi.nlm.nih.gov/pubmed/25057538.

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 225.

Salwen MJ. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 26.



Review Date: 2/2/2015
Reviewed By: Emily Wax, RD, The Brooklyn Hospital Center, Brooklyn, NY. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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