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Basic Nutrition Lesson Five - Introduction to Water-Soluble Vitamins
Part Two

By Shereen Jegtvig, About.com Guide

Updated July 26, 2009

About.com Health's Disease and Condition content is reviewed by our Medical Review Board

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Lean beef with healthy vegetables in the correct portion sizes.

Photo © Fiona Haynes

In part one of the introduction to water soluble vitamins, you learned that you don’t store water-soluble vitamins in your body very well so they need to be replaced constantly through your diet. You also learned more about vitamin C, thiamin and riboflavin.

Now in part two you will learn about the rest of the B complex vitamins, niacin, pantothenic acid, B6, B12 and biotin.

Niacin – B3

You need sufficient amounts of niacin in order to have a healthy digestive system, healthy skin and normal nervous system function. Like all B vitamins, niacin helps to convert the food you eat to energy. A deficiency in niacin could lead to a disease called pellagra. The symptoms include inflamed and damaged skin, digestive problems, and impaired cognitive function.

Niacin is often taken as a supplement to help control cholesterol levels and as an antiinflammatory agent. Taking large doses of niacin, over 250 mg, will cause a niacin flush. This is an itching, burning feeling in the joints and face that is accompanied by a red flush to the skin. The niacin flush is not dangerous, however larger doses of niacin may cause liver damage if taken for long periods of time. Niacin is very effective for control of cholesterol, however the dosage should be determined by a health care professional and if large doses are used, your liver function tests should be monitored.

Niacin and Diet

Niacin is abundant in dairy products, meats, poultry, fish, eggs, nuts, legumes and fortified breads and cereals.

The RDA for niacin

children age 4 to 8 need 8 mg
males age 9 to 13 need 12 mg
males age 14 and up need 16 mg
females age nine to 13 need 12 mg
females age 14 and up need 14 mg
pregnant females need 18 mg

Here are some foods that contain niacin:

one cup two percent milk – 0.224 mg
one-half cup sweet corn – 1.075 mg
one whole lime – 0.134 mg
one cup cooked pinto beans – 0.544 mg
six ounce pork chop – 3.287 mg
one egg – 0.031 mg
twelve almonds – 1.113 mg
one cup chopped chicken breast – 19.197 mg
three ounces tuna – 11.295 mg

Pantothenic Acid - B5

This vitamin is found in many foods so deficiencies are very rare. Vitamin B5 is needed for energy production and the formation of cholesterol, bile salts, fatty acids and some hormones.

The AI (adequate intake) for pantothenic acid

children age 4 to 8 need three mg
males age 9 to 13 need 4 mg
males age 14 and up need 5 mg
females age 9 to 13 need 4 mg
females age 14 and up need 5 mg
pregnant females need six mg

Pyridoxine – B6

Vitamin B6 is important for nervous system and muscle function. Pyridoxine may also ease the symptoms of premenstrual syndrome and menopausal discomfort. Vitamin B6 will also help keep homocysteine levels down, which may be important for cardiovascular health. Symptoms of vitamin B6 deficiency include weakness, nervousness, depression and memory loss.

B6 supplements are available, but care must be taken to follow label instructions. Very large doses of pyridoxine can cause permanent nerve damage when taken over long periods of times.

Pyridoxine and Diet

Pyrodoxine is found in a several foods, including meats, legumes, grains and vegetables. A balanced diet will provide you with enough vitamin B6 for normal health.

The RDA for pyridoxine

children age 4 to 8 need 0.6 mg
males age 9 to 13 need 1 mg
males age 14 to 50 need 1.3 mg
males age 50 and up need 1.7 mg
females age 9 to 13 need 1 mg
females age 14 and up need 1.4 mg
pregnant females need 1.8 mg

Here are some foods that contain pyridoxine:

one cup cooked green beans – 0.070 mg
one cup strawberries – 0.071 mg
six ounce pork chop – 0.305 mg
one slice whole wheat bread – 0.059 mg
one cup cauliflower – 0.222 mg
one ounce pecans – 0.060 mg
three ounces tuna – 0.350 mg

Folate – B9

Folate is well known as a vitamin needed for fetal neural tube development. Folate is also important for blood cell production and for healthy homocysteine levels. You will find folate in green leafy vegetables, fruits and legumes.

Folic acid is the supplemental form of folate and is a common nutritional ingredient in fortified foods.

A deficiency can result from not eating enough foods that contain folate or from taking any of a variety of drugs that deplete your body's folate or by heavy alcohol consumption. Symptoms of a folate deficiency include diarrhea, loss of appetite, weight loss, weakness, headaches, sore tongue and impaired mental function.