Why Do We Need The Vitamin B Group?

The B complex vitamins are a diverse group of nutrients that share many similar functions in your body. They are frequently found together in foods. All B vitamins are water-soluble, which means excess dietary intake is easily eliminated in your urine and most are not stored for extended periods of time in your tissues. Therefore, daily consumption of most B vitamins is required to avoid deficiency. Many B vitamins, such as niacin, thiamine and pyridoxine, must be activated in your cells before they can exert their physiologic effects.

Energy Production

In his book, "Staying Healthy with Nutrition," Dr. Elson Haas calls the B vitamins "catalytic sparkplugs" due to their participation in metabolizing energy molecules -- carbohydrates, proteins and fats -- in your cells. By serving as cofactors for enzymes in the cytoplasm of your cells, some B vitamins facilitate the breakdown of nutrients into simpler compounds, which can then be channeled into your mitochondria, where other B vitamins help to drive the energy-producing metabolic pathways.

Synthesis

B vitamins are not only involved in the degradation of energy molecules; several are instrumental in synthetic processes, as well. For example, thiamine, or vitamin B-1, is needed for the initial steps of fatty acid production, which is important for fat storage, cholesterol metabolism and the production of steroid hormones. Vitamins B-6, B-12 and folate participate in the manufacture of hemoglobin and DNA, which are required for red blood cell production. Additionally, B-12 is essential for producing and maintaining myelin, the protective insulation around your nerves.

Neurotransmitters

B vitamins play a vital role in the production and metabolism of neurotransmitters, which are chemical messengers used by your nervous system to relay impulses. For example, vitamin B-6 is needed by the enzymes that produce serotonin, dopamine, norepinephrine and gamma-aminobutyric acid, or GABA. Thus, vitamin B-6 deficiency can interfere with normal nervous system function and can even lead to seizures. Vitamin B deficiencies can also impair other neurotransmitter-regulated functions such as platelet activity and intestinal motion.

Sources

Many of the B vitamins tend to occur together in foods. Dr. Haas states that the richest natural source of B vitamins is brewer's yeast, although it is lacking in vitamin B-12. The bran and germ of cereal grains is another good source of many B vitamins, as are legumes and nuts. Liver is an excellent source of B complex vitamins, including vitamin B-12, which is only found in appreciable amounts in animal foods, such as red meats, fish and poultry. B complex supplements are also commercially available.

Considerations

A well-balanced diet that includes animal protein or a supplemental source of vitamin B-12 is the best way to ensure adequate intake of B vitamins. The recommended daily intake for this diverse group varies significantly, depending on the vitamin in question and your age, gender and pregnancy status. B complex supplements are often marketed according to the milligram content of the prominent B vitamins, such as "B Complex 50" or "B Complex 100." Since B vitamins are water-soluble, a good deal of latitude in dosing is usually well-tolerated. Ask your doctor about your specific B vitamin needs.