Food Product Design: Nutrition Notes - January 2001 - Treating Alzheimer's Disease Nutitionally

January 2001

Treating Alzheimer’s Disease Nutritionally By: Andrea Platzman, R.D.Contributing Editor

It is estimated that more than 20 million people suffer from Alzheimer’s disease worldwide — 4 million in the United States alone. That number is expected to grow threefold by 2050, as both the population and life-expectancy age grows.

Alzheimer’s disease (AD) is named after Alois Alzheimer, the German neurologist who first identified it in 1907. The cause is still unknown, but it may result from deterioration of the nerve fibers that carry information to and from the brain. Research shows that a lack of mental and physical exercise may contribute to the disease’s development, and an estimated 30% to 40% of people over age 85 have at least the mildest version of the disease.

The aging brainThe cognitive-power decline that normally accompanies aging is less dramatic than many people think. When the mind grows cloudy with age, there are possible causes, usually treatable, other than Alzheimer’s. These may include an underlying health problem such as hypothyroidism, diabetes or depression; a nutritional deficiency, usually of vitamin B12 or folic acid; or side effects of some medications.

Mind alteringJoshua Miller, Ph.D., assistant adjunct professor, department of pathology, University of California-Davis Medical Center, Sacramento, explains that: "Taking B vitamin supplements, folic acid, B12 and B6, to reduce plasma homocysteine levels, might be beneficial, but we don’t yet know for sure." However, a gross deficiency of vitamin B12 can cause a certain type of dementia and correcting the deficiency can sometimes restore clear thinking. Some research has shown that moderate deficiencies of vitamin B12 and folic acid elevate the homocysteine blood level, which may contribute to cognitive decline and the onset of Alzheimer’s disease.

Plaque deposits on the brain might promote oxidation — another reason that neurons are killed. According to Miller, the brain requires oxygen and polyunsaturated fatty acids and is therefore prone to lipid peroxidation. This leads to the production of free radicals that may attack and irreversibly damage neural tissue. Maintaining and optimizing antioxidant defenses, such as vitamin E, in the brain could be an important strategy for preventing or slowing the progression of cognitive decline, but more studies need to be done to confirm this theory. In one study, published in the April 24, 1997 New England Journal of Medicine, patients suffering from moderate Alzheimer’s disease showed a slowing of the disease’s progression by seven months when given high doses of vitamin E, but did not show improved cognitive function.

Ginkgo biloba also has shown promise in fighting Alzheimer’s based on a study published in an October 1997 issue of the Journal of the American Medical Association conducted by Dr. Pierre L. Le and colleagues at the New York Institute for Medical Research. However, a recent Dutch study headed by Dr. Martien van Dongen published in the October 2000 Journal of the American Geriatrics Society has not seen results that strongly support the earlier study.

Research recently completed by Sharoni Jacobs and colleagues, Salk Institute, La Jolla, CA, found direct evidence that vitamin A is required for memory and learning. Mice fed diets low in vitamin A from birth were impaired in long-term memory and learning, but the impairments were reversed when vitamin A was added to their diet.

Women develop Alzheimer’s disease more often than men of the same age, probably because of the postmenopausal drop in estrogen levels. Estrogen fights oxidation and inflammation and may boost the level of the beneficial chemical acetylcholine. Some studies have shown that using hormone replacement therapy in women may decrease the development of Alzheimer’s disease.

The omega-3 fatty acid docosahexaenoic acid (DHA) is an essential constituent of nervous tissue and accounts for 8% of the polyunsaturated fatty acids in the brain. "Studies are currently being done to evaluate the effectiveness of DHA on Alzheimer’s disease and other cognitive dysfunction diseases," says Deanna McCarthy, senior manager, scientific affairs, OmegaTech Inc., Boulder, CO.

The body uses phosphatidylserine (PS), a phospholipid found naturally in all healthy cells, to make acetylcholine. PS is especially concentrated in the brain where it helps keep neurons flexible to better transmit nerve impulses. Because both PS and acetylcholine levels decline with age, some studies have shown that supplementing with 200 to 300 mg of PS can improve memory. PS is found mostly in soy and lecithin, and more studies are being done on the effects of PS supplementation on cognitive dysfunction and Alzheimer’s disease.

Huperzine A, a purified compound of Chinese club moss (Huperzia serrata), inhibits the enzyme that breaks down acetylcholine. It is brewed as an herbal tea in China and is thought to work similarly to tacrine and donepezil, medications used to treat dementia. A recent study by D.L. Bai and colleagues, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China, tested the effects of 100 to 200 mcg of huperzine A and received positive results.

Future promisesHope for an Alzheimer’s cure may soon be answered through the development of new drugs. However, proper nutrition may still be important. "Since an increasing body of evidence has implicated vascular disease and vascular disease risk factors, including hypertension, diabetes, presence of the apolipoprotein E4 allele and hyperhomocysteintemia, as risk factors for cognitive deficits and Alzheimer’s disease, I strongly recommend following a heart-healthy diet," says Miller

Andrea D. Platzman is a registered dietitian who is a consultant to the food industry, and regularly writes for nutrition publications. She earned a master’s degree in nutrition from New York University, and has a strong culinary and business background.

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