There's no doubt that the nervous system and brain require their fair share of food and oxygen to grow and thrive. The 100 billion nerve cells that make up the brain and about two percent of the body are very metabolically active. A busy, hungry brain is also sensitive to the ups and downs of nutrients in the blood. Without its own nutritive supply, the brain depends on the rest of the body to feed it.
B vitamins are an important part of the brain's diet. Many of them help form neurotransmitters, the chemical messengers of the nervous system. Pyridoxal phosphate, a B6 member, is pivotal in the synthesis of the neurotransmitters serotonin, dopamine and gamma-amino butyric acid (GABA) (1). When thiamine is too low, the neurotransmitters glutamate and aspartate also decline. Choline, the vitamin-like cousin of B complex, is needed for acetylcholine.
B Vitamins and Health
Medical journals are brimming with hard-to-pronounce neurological and behavioral conditions that occur when B vitamins are in short supply. Besides emotional, cognitive and behavioral symptoms, inadequate B vitamins can bring on physical complaints too.
While neuropathies, a general term for disorders of the nervous system, can be caused by any number of nutritional deficiencies, B vitamins account for many of them. Pellagra, a niacin-deficient state, and beriberi, due to low thiamin, are probably the most well known of the B deficiency conditions. Beriberi in this country is usually associated with alcoholism, but not always.
The Mayo Medical Center in Rochester, Minnesota reported a case of a 66 year old woman who complained of irritability, loss of appetite, and nausea among other symptoms. Her doctors determined that her sparse diet of fruit cocktail, pop and popsicles, not surprisingly low in thiamin, was responsible. This patient displayed mental changes seen in cerebral beriberi called Wernicke's encephalopathy. If left untreated, this brain disorder can progress to the more serious Korsakoff's psychosis. She was given thiamin and eventually recovered (2).
Psychiatric conditions, not typically thought of as B deficient disorders, have also been treated with various B vitamins. Some physicians have given B6 (3), niacin (4) and folate (5) to their schizophrenic patients. Other psychiatric disorders have also been treated with various B vitamins (6).
Most of us, however, are not battling neuropsychiatric illnesses. Still there's plenty of examples of more common conditions affected by poor B nutrition.
Hungarian scientists discovered that folic acid, alone or with a multivitamin supplement, prevents recurrent neural-tube defect, a type of birth defect. These researchers suggested that all women planning a pregnancy should take folic acid (7). The Center for Disease Control in Atlanta went one step further and advises that all women who "could" become pregnant take this B vitamin (8).
Once a baby is born, the mother must ensure he is properly fed. Thirty-five years ago a proprietary formula, where B6 was inadvertently destroyed during sterilization, caused widespread seizures in infants. The newborns were cured with a B6 supplement, but this situation dramatically shows the impact B vitamins have on the nervous system (1). (By the way, babies who are breast fed by mothers eating a low B6 diet can also have seizures.)
Some neurological childhood conditions also appear to be connected to B vitamins. An interesting study done 20 years ago at Saint Joseph Hospital in Pennsylvania found low serotonin levels in hyperactive children. The investigators fed some of the subjects B6, and observed the neurotransmitter, serotonin, rise appreciably (9). Autism, also called infantile psychosis, has been treated with B6 as well (10).