Vitamin B Recommended Dosage

The B vitamin complex constitutes a group of eight vitamins that function in cell growth and development, as well as energy and red blood cell production. Adequate intake of the B vitamins daily is important as part of a balanced diet and may help prevent development of such conditions as heart disease.

About the B Vitamins

The B vitamin complex includes thiamin, riboflavin, niacin, pantothenic acid, vitamin B-6, biotin, folic acid, and vitamin B-2. Thiamin, niacin, and riboflavin function in energy production and affect the enzymes that influence the muscles, nerves, and heart, while pantothenic acid influences normal growth and development. Vitamin B-6 and B-12 function in protein breakdown and are necessary for the health of red blood cells, the nervous system and parts of the immune system, with vitamin B-12 assisting in the body's use of folic acid. Folic acid also assists in the production of red blood cells, as well as helping the cells make and maintain DNA, while biotin functions in the breakdown of protein and carbohydrates and assists in the production of hormones.

Vitamin B Health Effects

Deficiency of B vitamins can weaken the immune system and cause symptoms such as anemia, fatigue, loss of appetite, abdominal pain, depression, and muscle cramps. On a positive note, adequate intake of B vitamins, especially folic acid, may decrease the risk of heart disease. A report from the Harvard School of Public Health showed that folate supplementation decreases levels of homocysteine in the blood, which can cause clogging of the arteries in high amounts. In addition, folate supplementation in pregnant women can decrease the risk of birth defects in the fetus.

Vitamin B Recommended Intake

According to the Institute of Medicine, the daily recommended intake for most adults is 1.1 to 1.3 mg of thiamin and riboflavin, 14 to 16 mg of niacin, 1.3 to 1.7 mg of vitamin B-6, 400 micrograms of folate and 2.4 micrograms of vitamin B-12. The adequate intake (AI) for pantothenic acid is 5 mg and 30 micrograms for biotin.

Vitamin B Sources

The recommended intake of B vitamins can be reached through daily consumption of animal products such as meat, fish, poultry, eggs, and dairy products, as well as leafy green vegetables, beans, peas, and whole grain products. Beef liver and clams are the richest source of vitamin B-12, while fortified cereals are a rich source of vitamin B-6. In addition, biotin and folic acid can be found in citrus fruits such as oranges and grapefruits, while vitamin B-6 and biotin can be found in bananas. Daily consumption of a balanced diet of lean meats, dairy products, whole grains, fruits, and vegetables will ensure adequate intake of B complex vitamins.