Vitamins

Vitamins and their functions and sources
Date updated: February 06, 2009
Debby Golonka, MPH
Content provided by Healthwise
The tables below list the vitamins, what they do in the body (their functions), and their sources in food.
Water-soluble vitamins
Water-soluble vitamins travel freely through the body, and excess amounts usually are excreted by the kidneys. The body needs water-soluble vitamins in frequent, small doses, and these vitamins are not as likely as fat-soluble vitamins to reach toxic levels. However, niacin, vitamin B6, folate, choline, and vitamin C have upper consumption limits. Vitamin B6 at high levels over a long period of time has been shown to cause irreversible nerve damage.
A balanced diet usually provides enough of these vitamins. People older than 50 and some vegetarians may need to use supplements to get enough B12.
Water-soluble vitamins
Nutrient Function Sources
Thiamine (vitamin B1)
Part of an enzyme needed for energy metabolism; important to nerve function
Found in all nutritious foods in moderate amounts: pork, whole-grain or enriched breads and cereals, legumes, nuts and seeds
Riboflavin (vitamin B2)
Part of an enzyme needed for energy metabolism; important for normal vision and skin health
Milk and milk products; leafy, green vegetables; whole-grain, enriched breads and cereals
Niacin (vitamin B3)
Part of an enzyme needed for energy metabolism; important for nervous system, digestive system, and skin health
Meat, poultry, fish, whole-grain or enriched breads and cereals, vegetables (especially mushrooms, asparagus, and leafy, green vegetables), peanut butter
Pantothenic acid
Part of an enzyme needed for energy metabolism
Widespread in foods
Biotin
Part of an enzyme needed for energy metabolism
Widespread in foods; also produced in intestinal tract by bacteria
Pyridoxine (vitamin B6)
Part of an enzyme needed for protein metabolism; helps make red blood cells
Meat, fish, poultry, vegetables, fruits...