The Health Benefits & The Daily Allowance Of Vitamin B

The B vitamins represent a family of chemicals that include vitamins B-1, B-2, B-3, B-5, B-6, B-7, B-9 and B-12. Each has a specific function in the body, and some B vitamins have a number of identified functions. Their ubiquitous roles in the body illustrate the importance of maintaining a proper daily dose of B vitamins. B vitamins can be obtained from supplements or from proteins such as fish, chicken, meat and eggs. Leafy green vegetables, beans and green peas are another good source, as are some breads and fortified cereals.

Preventing Birth Defects

Vitamin B-9 (folic acid) is crucial in preventing some birth defects, says the National Institutes of Health (NIH). This vitamin is required so the embryonic central nervous system can form and grow properly. A maternal deficiency of vitamin B-9 can result in the birth defects known as anencephaly and spina bifida, which causes the brain and spinal cord, respectively, to not form within their bony cavities. Instead, these structures become exposed to the fetus's exterior. The result can be profound neurological impairment or death.

Nervous System Functions

The B vitamins are important to various neurological functions in the body. Vitamin B-6 (pyridoxine) is being investigated for its contribution to headaches, depression, seizures, Parkinson's disease and other neurological problems, says NIH. It is required for synthesizing two brain neurotransmitters, serotonin and dopamine, which are chemicals that nerve cells use to communicate.

Vitamin B-12 (methylcobalamin) also helps prevent nerve problems and may facilitate recovery of some effects of Bell's palsy. If a diet is deficient in vitamin B-12, it may lead to conditions such as leg and arm spasticity, gait disturbance or bladder and bowel dysfunction. Vitamin B-1 (thiamine) may assist with the brain's cognitive functions.

Blood Glucose

Vitamin B-6 is an important component of maintaining blood glucose within normal levels throughout the day. As the body's calorie intake drops, it uses vitamin B-6 to help convert stored carbohydrates and other nutrients to glucose in order to keep blood glucose levels within a normal range. A deficiency of vitamin B-6 can hinder the body's ability to maintain normal blood glucose; however, B-6 supplements will not enhance the ability to maintain normal blood glucose if the person is already well nourished, says NIH.

Other Functions

Vitamin B-9 is shown conclusively to lower the risk of cancer when taken in the recommended amounts, says the American Cancer Society. Vitamin B-6 is needed to manufacture proteins and to metabolize enzymes, says NIH.

Vitamin B-12 and vitamin B-5 (pantothenic acid) in the diet can help fight anemia. Vitamin B-5 also is needed to maintain immune and gastrointestinal function.

Vitamins B-12 and B-2 (riboflavin) are important for creating new erythrocytes (red blood cells). Vitamin B-1 can enhance circulation of blood through the body.

Recommended Dietary Allowance (RDA)

The NIH publishes the adult RDA for most B vitamins. The RDA for B-9 in pregnant women is 600 mcg. The RDA of B-12 is 2.4 mcg. The RDA for B-6 is 1.3 mg for ages 19 to 50 years and 1.5 to 1.7 for ages over 50 years. The RDA for B-1 is 1.1 to 1.2 mg. The RDA for B-2 is 1.1 to 1.3 mg. The RDA for B-5 is 5 to 10 mg.