Nutrition And Neurologic Disorders

The brain and nervous system require the full complement of essential nutrients and energy to develop and maintain their neurons and supporting cells. A deficiency of any one of these essential nutrients may impair the structure or functionality of the neurologic system.

Stroke is the most common life-threatening neurologic disease. Other neurologic conditions are, epilepsy, chronic headaches, and Alzheimer's disease.

The brain metabolizes 100 g to 150 g of glucose per day. During starvation, it adapts and uses ketones, derived from the breakdown of body fat stores, for energy and thus spares blood glucose and conserves body protein.

Severe deficiencies of vitamins, especially the B-complex group, impair nervous system function. Thiamin deficiency causes beriberi neuropathy as well as a peripheral neuropathy and polyneuritis that leads to paralysis of the eye muscles, loss of muscular coordination, and memory loss, especially in long-term alcoholics. Inadequate niacin intake causes pellagra, with symptoms that include intellectual impairment and dementia. Deficiency caused by vitamin B12 malabsorption in untreated pernicious anaemia, or as a result of a long term deficient vegetarian diet, can result in subacute degeneration of the spinal cord, optic nerves, cerebral white matter, and peripheral nerves. Severely deficient intakes of other vitamins of the B-complex group also affect neurologic function. In the early stages, these symptoms are readily overcome by increased dietary intake of the appropriate vitamins, but nerve damage in later stages are irreversible.

Deficiencies of other nutrients relate to defects in the nervous system function. Iodine deficiency during brain development causes mental retardation and neuromotor abnormalities. Chronic iron deficiency is associated with deficits in cognitive abilities. Vitamin E deficiency can cause spinal cord, cerebellar, and peripheral nerve degeneration with muscle wasting.


Stroke is the sudden loss of brain function caused by thrombosis, embolism, stenosis, atherosclerosis, or haemorrhage from rupture of a cerebral artery. These events deprive the brain of oxygen and cause tissue death and irreversible damage to nervous tissue. Symptoms range from those too trivial for the victim to notice to major sensory deficits, blindness, paralysis, speech loss, coma, and death.

Persons at greatest risk for stroke are those with hypertension and diabetes, and those who smoke cigarettes and display impaired cardiac function due to coronary heart disease, congestive heart failure, or hypertensive heart disease. These major risk factorsfor stroke are related to nutritional, dietary, and lifestyle factors.

Moderate sodium intake, high potassium intake, vegetarian diets, calcium, weight reduction, and alcohol restriction all have been suggested as factors associated with lowering the risk factor for stroke in humans.


Headache is one of the most common complaints evaluated by neurologists. The foods most frequently implicated contain tyramines (eg. cheese, red wines), or phenylethylamine (eg. chocolates). The "Chinese Restaurant Syndrome" is associated with numbness around the mouth, tingling, flushing of the face, dizziness, and headache. This syndrome could be attributable to the high quantity of monosodium glutamate (MSG) used in the prepared foods.


Low levels of magnesium can cause seizures, and the magnesium-deficient rat is used as a model of experimental epilepsy. [Buck, D.R., Mahoney, A.W., and Hendricks, D.G.: Preliminary report on the magnesium deficient rat as a model of epilepsy. Laboratory Animal Science. 28(6),680-85, 1978.] Magnesium deficiency in humans most often results from kidney disease and is not a significant cause of epilepsy in people.

Vitamin Intake and Drug-Nutrient Interactions

Excessive intake of vitamin A causes reversible intracranial hypertension, headache, blurred vision, seizures, end encephalopathy. Excessive pyridoxine has been associated with peripheral nerve deterioration.

Naturally occurring food-borne toxins also affect the mature nervous system. Specific dietary constituents, such as heavy and trace metals, may have adverse effects on the nervous systems of older adults. Increased amounts of aluminum and calcium have been reported in brains of patients with Alzheimer's disease.

Some of the drugs used to treat neurologic disease can lead to vitamin deficiencies by changing the metabolism of vitamins, causing a secondary impairment of brain function. Dilantin, used to treat epilepsy, can increase folate requirements and cause vitamin K deficiency. Hydralazine can cause neuropathy, tranquilizers such as chlorpromazine and other phenothiazines may cause hyperphagia and weight gain. Monoamine oxidase inhibitors can cause acute hypertensive crises, including excruciating headaches or fatal intracranial haemorrhages, when taken with foods or beverages high in tyramine. Caffeine, found in foods and drugs, is an active pharmacologically active agent that can enter the brain because of its lipid solubility.

Nutrition Programs and Services

Food Labels:
Evidence related to the role of dietary factors in stroke and other neurologic diseases supports the need for sodium labeling of packaged food products.

Food Services:
Food service programs should emphasize diets low in sodium and calories to maintain ideal body weight and to control obesity and diabetes. [The Surgeon General's Report on Nutrition & Health, 1988.]

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