Diet & Brain Health

Cells in the brain and central nervous system require specific nutrients to function properly, just as any other cell in the body does. This begins in the embryo, where certain nutrients must be present so that the nervous system can develop normally. In adults, a lack of particular nutrients, such as vitamins, can lead to various neurological dysfunctions. These can manifest either as psychological or physiological problems.

Brain Function

Immediately after conception, the brain requires adequate folic acid from the mother's diet to develop normally. The National Institutes of Health, or NIH, warns that if the mother's diet is deficient in folic acid, a grave birth defect called anencephaly can occur, in which the head end of the neural tube fails to close early in fetal development, much of the brain does not develop at all and what does develop is exposed -- not enclosed by the skull -- resulting in profound problems.
The normal adult brain also depends on vitamin B6 to manufacture enzymes and the neurotransmitters dopamine and serotonin. It is also needed to aid in protein metabolism. Vitamin B6 deficiency may also be involved in seizure disorders, Parkinson's disease, depression and many pain disorders. Vitamin B12 aids with various cell functions and with making DNA. The Internet Journal of Nutrition and Wellness advises that deficiencies of B12 may be associated with psychosis and dementia.

Brainstem and Spinal Cord Function

The spinal cord and brainstem also require folic acid to develop normally. Lack of maternal folic acid can produce the birth defect known as spina bifida, according to the NIH. In the more severe types of this condition, the spinal cord is exposed, leading to severe and permanent neurological damage. Other spinal cord abnormalities can result from vitamin B12 deficiency in the adult diet. The NIH advises that these problems may be caused by nerve cell degeneration, manifesting as spasticity, walking impairments and difficulty with limb coordination.

Peripheral Nerve Function

Lack of vitamin B6 in the adult diet may result in neuropathy, or peripheral nerve problems in which nerves are unable to conduct signals normally, resulting in sensory and motor impairment. The NIH advises that either very high or very low levels of vitamin B6 can cause neuropathy, and its involvement in neuron damage is currently under investigation. Vitamin B12 deficiency can also cause peripheral nerve damage. The NIH advises that this may manifest as weakness or numbness in the arms and legs. More severe deficiencies may be evident as problems with the bowels and genitourinary systems and may result in impotence in men.

Recommended Dietary Allowance

The Office of Dietary Supplements (ODS) of the NIH publishes the Recommended Dietary Allowance (RDA) for nutrients such as vitamins. For folic acid, the RDA for pregnant women or those about to be pregnant is 600 micrograms. For all adults 19-50 years old, the ODS has determined an RDA for vitamin B6 of 1.3 mg. For those above age 50, the RDA for vitamin B6 is 1.5 mg for women and 1.7 mg for men. The RDA for vitamin B12 in adults is 2.4 micrograms.

Food Sources

The ODS publishes a list of foods that contain the highest concentrations of nutrients and vitamins. An abundance of folic acid can be found in fortified breakfast cereals, beef liver and certain vegetables such as spinach, asparagus, cowpeas, peas, white rice and broccoli. Vitamin B6 is abundant in fortified breakfast cereals, various fish, poultry, meat, beans, vegetables and fruit. Vitamin B12 is concentrated in foods such as meats, poultry, various fish, eggs and milk.