There are many other circumstances where B vitamins help with neurological problems. Vitamin B6 is used for women suffering from depression due to the birth control pill or premenstrual syndrome (11). It also helps some cases of carpal tunnel syndrome, where the median nerve is painfully compressed within the wrist (11). There's even a type of rare epilepsy that retreats when B6 is given (12).

Researchers are also analyzing the subtle behavioral and neurological changes that result from mild deficiencies. At one time doctors would admit a vitamin was lacking only with laboratory evidence or well established deficiency symptoms. Experts have discovered that individual tissues, not necessarily the whole body, can be low in a vitamin. They're also realizing that vitamin requirements might be higher, especially for specific functions, than previously thought. As research continues, the biochemical roles of vitamins are expanding (13).

Slightly low levels of niacin, for instances, may lead to depression, apprehension, hyper-irritability, emotional instability and impairment of recent memory. Marginal thiamin deficiency could, in only five days, cause lassitude (14).

"It is possible that some of the decline in cognitive function associated with aging is preventable or reversible with improved vitamin nutriture especially vitamin B-12, vitamin B6, and folate," say investigators at the US Department of Agriculture Human Nutrition Research Center on Aging. Some typical psychiatric conditions seen in older citizens, especially depression and even Alzheimer's, may be due to or exacerbated by poor nutrition. Sadly, low vitamin levels could simmer for months or years without any overt signs (15). Decreased stomach acid (which increases with age), poor eating, chronic illness, medications or institutionalized care may contribute to inadequate B vitamins and other nutrients (16).

Where Have All the B Vitamins Gone?
Modern day lifestyle is not very B vitamin friendly. The manner in which we grow and handle food, our medicines and habits are rough on the fragile members of B complex. Each B vitamin responds differently to its environment with some hardier than others. Here are a few ways the B's suffer.

This epic begins in the field. Agricultural factors such as the soil, climate, fertilizers used and other growing conditions influence a food's vitamin content. How ripe or mature a food is when picked determines its nutritional value. Processing foods, like milling flour or grains, curing meats, irradiation, canning, freezing, sulfite use, milk pasteurization and evaporation, also tamper with B vitamin nutriture

Once a food finds its way into your kitchen, it endures another set of B vitamin challenges. Peeling a fruit or vegetable removes much of its goodness (though for highly sprayed produce this is probably wise.) Cooking conditions, which vary widely from cook to cook, rob a few more of the B's. Finally, the longer you store food, the more you lose. Light is especially hard on nutrients, especially B6 and riboflavin.

Next, the B vitamins must survive the route from your plate to needy spots in your body. Virtually no vitamin is absorbed 100 percent. Even less is absorbed, however, if there's intestinal damage or low stomach acid. Nutrient status influences how well we use other vitamins and minerals in our food. Absorption of, example B12, decreases with an iron or B6 deficiency.