Although every major organ is critical to physiological functioning, one might say that the brain is the body's dictator. This three-pound, walnut-shaped organ encased in the skull orchestrates an astounding array of functions throughout the body. As Richard Restak, M.D., notes: "The human brain can store more information than all the libraries in the world. It is also responsible for our most primitive urges, our loftiest ideals, the way we think. ... The workings of an organ capable of creating Hamlet, the Bill of Rights and Hiroshima remain deeply mysterious."¹

Naturally, medical researchers have been trying to crack the mystery for years. In their efforts to analyze the central nervous system, they discovered that complex brain functions depend on a balance of nutrients. Increasing evidence demonstrates that nutrient deficiencies and chemical imbalances can disrupt both emotional and psychological well-being.

It May Not Be Alzheimer's
One of the most common indications of deteriorating brain function is memory loss. Many older people, when they become aware of memory lapses, jump to the conclusion that they are experiencing the early signs of Alzheimer's disease, when in fact their declining memory may be rooted in a nutritional deficiency.

In the mid-1940s and 1950s, scientific research clearly showed that healthy brain functioning depends on sufficient amounts of B vitamins. Experts today still tout the importance of B vitamins, particularly the following five (keep in mind that these vitamins are all water-soluble and should be taken together for maximum benefit):

B1 (thiamine) helps convert glucose to energy. It also mimics acetylcholine (a neurotransmitter involved in memory) and plays a role in brain functions related to memory and cognition.² Chronic, heavy alcohol consumption can cause a thiamine deficiency resulting in Wernicke-Korsakoff syndrome, a disease marked by mental confusion. Severe thiamine deficiency leads to beriberi, a disease characterized by weakness, wasting, nerve inflammation and numbness of the hands and feet. A recent study shows that high-dose thiamine supplementation (3-8 g/day) may actually decrease the deleterious effects of senility.³ Thiamine supplementation also appears to elevate mood. In another study, 120 young women took either placebo or 50 mg thiamine daily for two months. Before-and-after tests assessed mood, memory and reaction times. Women who took the thiamine supplements reported feeling significantly more clearheaded, composed and energetic.⁴

B3 (niacin) enhances the ability of red blood cells to carry oxygen. It is also vital to the formation and maintenance of many tissues, including nerve tissue. A severe niacin deficiency produces pellagra, a disease characterized by the three Ds: dermatitis, diarrhea and dementia.

B6 (pyridoxine) is needed for the production of amino acid-derived neurotransmitters such as norepinephrine, serotonin and dopamine. B6 deficiency can cause many ailments including slow learning and visual disturbances. Low levels of this vitamin may also provoke epileptic seizures in people prone to them.

B12 (cobalamin) plays an important role in the formation of the myelin sheath around nerve fibers. It also helps the body transport and store folic acid. Vitamin B12 deficiency can cause pernicious anemia, nerve dysfunction (weakness, poor reflexes and strange sensations in the arms and legs) and impaired mental activity. It has also been linked to depression, especially in the elderly.⁵

Folic acid is necessary for DNA synthesis, hence it plays an essential role in all cell divisions and in the development of the fetal nervous system. Folic acid deficiency can lead to megaloblastic anemia and poor growth in children and can also contribute to various psychiatric disturbances including depression. As many as 31 to 35 percent of all depressed patients have folic acid deficiencies.⁶ Folic acid supplementation is perhaps most widely known for preventing neural tube defects in the developing fetus.⁷

The following nutrients related to the B vitamins can also enhance brain functioning:

Choline, a component of lecithin, is critical to memory, learning and mental alertness. Manufacture of cell membranes and the neurotransmitter acetylcholine depend on it. Choline helps increase the amount of acetylcholine in the memory circuits of the temporal lobe.⁸ Although supplemental choline improves memory performance in younger people, it has failed to consistently help elderly adults who already suffer from memory loss or Alzheimer's disease.

Inositol, although not officially a B vitamin, is recognized as part of the B complex. It occurs in cell membranes as phosphatidylinositol. The neurotransmitters serotonin and acetylcholine both require phosphatidylinositol for proper functioning.
Two clinical trials have shown that rather large amounts of inositol can improve certain psychiatric disorders. In a double-blind, controlled crossover study of 13 patients with obsessive-compulsive disorder conducted by Mendel Fux, M.D., and colleagues at Ben Gurion University of the Negev in Beersheva, Israel, 18 g/day of inositol for six weeks significantly lowered scores on the Yale-Brown Obsessive Compulsive Scale.⁹

Another study conducted by Joseph Levin, M.D., looked at the effects of taking inositol for four to six weeks in patients with depression (28 patients, 12 g/day); panic disorder (21 patients, 12 g/day); schizophrenia (12 patients, 12 g/day); obsessive-compulsive disorder (13 patients, 18 g/day); Alzheimer's disease (11 patients, 6 g/day); electroconvulsive therapy-induced memory loss (12 patients, 6 g/day); attention deficit disorder (11 children, 200 mg/kg/day) and autism (9 children, 200 mg/kg).¹⁰ Inositol had significant therapeutic effect for depression, panic disorder and obsessive-compulsive disorder illnesses that respond to ProzacTM.

Phosphatidylserine is the major phospholipid in the brain. Present in cell membranes, it plays a major role in determining their integrity and fluidity. The brain generally makes enough, but deficiencies of essential fatty acids or vitamins such as folic acid and B12 can inhibit production.

The potential benefits of phosphatidylserine on dementia and memory loss have been studied extensively. Results are fairly positive; most studies reported short-term cognitive gains in study participants. One of the larger double-blind, placebo-controlled studies followed more than 400 patients ages 65 to 93 who had moderate to severe cognitive decline. Compared to the placebo group, both cognitive and behavioral parameters improved significantly within the six-month study period for the phosphatidylserine-treated group.¹¹ Other studies indicate that phosphatidylserine may be particularly effective in improving cognition in the early stages of Alzheimer's disease.¹²

Docosahexaenoic acid (DHA), a polyunsaturated fatty acid also known as an omega-3 fatty acid, plays a critical role in infant brain development and vision. Before a child is born, DHA from the mother's blood travels to the placenta where it is used for membrane development in the brain and retina.¹³ Research has also linked the rising rate of depression among adults to an imbalance in the ratio of omega-3 fatty acids to omega-6 fatty acids (arachadonic acid).¹⁴

Amino Acids
Amino acids, the building blocks of protein, are critical to the formation and functioning of neurotransmitters. Of the 20 amino acids, two are particularly important to brain function: L-tyrosine and L-tryptophan.

L-tyrosine, one of the nonessential amino acids found in protein-rich foods such as meat, poultry, seafood and tofu is a precursor to the neurotransmitters norepinephrine and dopamine. These chemical messengers promote mental acuity and alertness. Increased levels of these neurotransmitters can affect mood and behavior, fostering a tendency to think more quickly and react more rapidly.¹⁵

L-tryptophan is integral to the production of serotonin, a neurotransmitter with sedative and sleep-promoting effects. L-tryptophan is found in foods such as bananas, milk and sunflower seeds. Once available as a supplement, it was recalled by the Food and Drug Administration (FDA) in 1989 because of reported neuromuscular side effects. Although these effects were later traced to a bacterial contaminant from a single manufacturer, the FDA has not withdrawn its ban of over-the-counter L-tryptophan sales.
[Supplemental 5-HTP (5-Hydroxy Tryptophan) is now available, however; please read the article on that nutirent]

Minerals
Iron, magnesium, calcium, copper and zinc all help keep the body functioning smoothly. Proper balance of these minerals is especially critical to brain performance; even a slight imbalance may create psychological disturbances. Here are highlights of the most important mineral functions.

Iron is particularly critical to motor and mental development during infancy. An iron deficiency can adversely affect the ability to learn and understand new information and may result in poor concentration and attention span.¹⁶

Calcium and magnesium regulate nerve impulses and aid in the formation of neurotransmitters. Excessive levels of calcium may result in mental changes--the extreme being stupor or even coma.¹⁷

Zinc deficiency may contribute to dementing illnesses such as Alzheimer's disease. A small study suggests that supplemental zinc may provide benefits in cases of dementing illness.¹⁸

The sophisticated chemistry of the brain depends on all of these nutrients, but further research is needed to elucidate the effects of supplementation on various central nervous system disorders.

Michelle Badash has 12 years of experience working at a nutrition research center in Boston. She has written and edited a newsletter about nutrition research and is also a free-lance writer.

REFERENCES
1. Restak, R. The Brain: 1. New York: Bantam Books, 1984.

2. Meador, K.J., et al. "Evidence for a central cholinergic effect of high dose thiamine." Ann Neurol, 34: 724-26, 1993.

3. Benton, D., et al. "The impact of long-term vitamin supplementation on cognitive function." Psychopharmacology, 117: 298-305, 1995.

4. Benton, D., et al. "Thiamine supplementation for mood and cognitive functioning." Psychopharmacology, 129: 66-71, January 1997.

5.Godfrey, P.S.A., et al. "Enhancement of recovery from psychiatric illness by methyl folate." Lancet, 336: 392-95, 1990.

6. Crellin, R., et al. "Folates and psychiatric disorders: Clinical potential." Drugs, 45: 623-36, 1993.

7. MRC Vitamin Study Research Group, "Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study." Lancet, 338: 131-37, 1991.

8. Vernon, M., & Jeffrey, M. Brain Power: A Neurosurgeon's Complete Program to Maintain and Enhance Brain Fitness Throughout Your Life: 139. New York: Houghton Mifflin, 1989.

9. Fux, M., et al. "Inositol treatment of obsessive-compulsive disorder." Am J Psychiatry, 153: 1219-21, 1996.

10. Levine, J. "Controlled trials of inositol in psychiatry." Eur Neuropsychopharmacol, 7: 147-55, May 1997.

11. Cenacchi, T., et al. "Cognitive decline in the elderly: A double-blind, placebo-controlled multicenter study on efficacy of phosphatidylserine administration." Aging, 5: 2, 123-33, April 1993.

12. Crook, T., et al. "Effects of phosphatidylserine in Alzheimer's disease." Psychopharmacol Bull, 28: 61-66, 1992.

13. Carlson, S.E., et al. "Synopsis: Dietary omega-3 fatty acids and the development of the brain and retina in human infants." NOAA technical memorandum, NMFS-SEFSC-367, NIH meeting on omega-3 fatty acid research, May 12, 1994.

14. Hibbeln, J., & Salem, N. "Dietary polyunsaturated fatty acids and depression: When cholesterol does not satisfy." Am J Clin Nutr, 62: 1-9, 1995.

15. Vernon, M., & Jeffrey, M., op. cit., 137.

16. Oski, F. "Iron deficiency in infancy and childhood." New England J Med, 329: 190-93, 1993.

17. Garrison, R. & Somer, E. The Nutrition Desk Reference. New Canaan, Conn.: Keats Publishing Inc., 1995.

18. Constantinidis, J. "Treatment of Alzheimer's disease by zinc compounds." Drug Develop Res, 27: 1-14, 1992.