As a group they are named the B complex vitamins because they are commonly found together in foods and have similar coenzyme functions, often needing each other to perform best. Certain of the B vitamins can also be made in the body by inhabitant microorganisms, primarily in our large intestine. Bacteria, yeasts, fungi, and molds are all capable of producing B vitamins.

These vitamins are fairly easily digested from food or supplements and then absorbed into the blood, mainly from the small intestine. When the amount of Bs taken exceeds the body's needs, the excess is easily excreted in the urine, giving it a dark yellow color. Excesses of certain B vitamins, such as thiamine (B1), are also eliminated in our perspiration. Since there are many deficiencies and no known toxicities of the B vitamins, taking modest excesses is really of no concern and may be helpful to many people. However, taking huge quantities is probably not needed under most conditions.

Sources: The B vitamins are found in many foods, and they often occur together. Actually, in nature, there is no B vitamin found in isolation. Heating, cooking, acid, and alkali affect each vitamin differently, so check the sections on individual Bs for this information.

The richest natural source containing the largest number of B vitamins is brewer's yeast, or nutritional yeast. Yeast is a common source used to make B vitamin supplements as well. However, this is not necessarily an ideal food for many people, since sensitivities to yeast may cause digestive tract problems or allergy. Different yeasts may also vary in their concentrations of specific B vitamins.

The germ and bran of cereal grains are good sources of these vitamins, as are some beans, peas, and nuts. Milk and many leafy green vegetables may also supply small amounts of B vitamins. Liver is an excellent source of the B complex vitamins. Other meats, such as beef, are fairly low, except for B12, which is found mainly in animal foods. Check the discussion of each individual B vitamin for its best sources. And remember, the B vitamins are produced by human intestinal bacteria, which seem to work best with the milk sugar and fats in our diet, though most foods can provide a source for this biodynamic B vitamin production in the colon. Antibiotics such as sulfa drugs and tetracyclines, which kill the intestinal bacterial flora, also lower our potential to produce B vitamins. Replacing the lactobacillus intestinal bacteria after taking antibiotics is important in maintaining the health and microbial ecosystem in the colon.

Functions: The B vitamins are the catalytic spark plugs of our body; they function as coenzymes to catalyze many biochemical reactions. B vitamins help provide energy by acting with enzymes to convert carbohydrates to glucose and also are important in fat and protein/amino acid metabolism.The B complex vitamins are very important for the normal functioning of the nervous system and are often helpful in bringing relaxation or energy to individuals who are stressed or fatigued. The health of the skin, hair, eyes, and liver is influenced by the B vitamins, as is that of the mucosal linings, especially in and around the mouth. The general muscle tone of the gastrointestinal tract is also enhanced with proper levels of B vitamins, allowing the bowels to function most efficiently.

Uses: The functions of the B vitamins are so interrelated that it is suggested they be taken combined in B complex food supplements. They are usually part of any multiple vitamin and are often taken in increased amounts for problems of stress, fatigue, anxiety and nervousness, insomnia, and hyperactivity. B vitamins are also used for many kinds of skin problems, especially dry or itchy dermatitis rashes, or cracks at the corners of the mouth. Some cases of vitiligo may be helped by B complex supplements, including higher amounts of PABA. Premenstrual and menopausal problems may be helped with additional B complex vitamins. Treatment of alcoholism and withdrawal from alcohol may be aided by taking large amounts of the B vitamins.

A wide range of various B vitamin deficiency symptoms can be treated with supplemental Bs. The natural food extract supplements are often preferred over the synthetic B complex because they seem to work more harmoniously and are more easily tolerated; in addition, it is likely that there are other enzymes, cofactors, and possibly even undiscovered B vitamins within the natural supplements.

Deficiency and toxicity: There are basically no real toxicity problems with any of the B vitamins, even in large amounts, since the body readily eliminates the excesses. There may be, of course, some subtle problems from taking high-dose individual B vitamins for too long. One such problem with taking large amounts of a single B vitamin is that this may cause a depletion of other Bs. Therefore, it is best to take a complete B complex supplement whenever taking any individual B vitamin regularly in higher amounts.At least thirteen B vitamins are found in our food. Some may be lacking in many Americans' diets because of the consumption of refined flour products, sugar, coffee, and alcohol, which can deplete B vitamins. Deficiency symptoms include fatigue, irritability, nervousness, depression, insomnia, loss of appetite, sore (burning) mouth or tongue, and cracks at the corners of the mouth. Some deficiencies may also reduce immune functions or estrogen metabolism; other potential problems are anemia, especially from vitamin B12 or folic acid deficiency, constipation, neuritis, skin problems, acne, hair loss, early graying of the hair, increased serum cholesterol, and weakness of the legs, to name a few.

Requirements: The daily amount required for each of the B vitamins varies, and the RDA is not very high for any of them. (For specific values, see the separate discussions of the various Bs.) The overall recommended minimums may be too low, and most people who take B vitamins take much higher amounts than the RDA. Since the body does not store much of the B complex vitamins and many commonly used, diet-related substances such as sugar, coffee, and alcohol deplete B vitamins in the body, these B vitamins should be taken daily. B vitamins are needed for growth, so increased amounts are also suggested for children and for pregnant or breast-feeding women. Stress, infections, and high-carbohydrate diets also may cause greater requirements of of B vitamin supplements.