Several herbal remedies and other dietary supplements are promoted as effective treatments for Alzheimer's disease and related disorders. Claims about the safety and effectiveness of these products, however, are based largely on testimonials, tradition, and a rather small body of scientific research. The rigorous scientific research required by the U.S. Food and Drug Administration for the approval of a prescription drug is not required by law for the marketing of dietary supplements.

Although many of these remedies may be valid candidates for treatments, there are legitimate concerns about using these drugs as an alternative or in addition to physician-prescribed therapy:

Effectiveness and safety are unknown

The maker of a dietary supplement is not required to provide the U.S. Food and Drug Administration (FDA) with the evidence on which it bases its claims for safety and effectiveness.

Purity is unknown

The FDA has no authority over supplement production. It is a manufacturer's responsibility to develop and enforce its own guidelines for ensuring that its products are safe and contain the ingredients listed on the label in the specified amounts.

Bad reactions are not routinely monitored

Manufacturers are not required to report to the FDA any problems that consumers experience after taking their products. The agency does provide voluntary reporting channels for manufacturers, health care professionals, and consumers, and will issue warnings about products when there is cause for concern. Dietary supplements can have serious interactions with prescribed medications. No supplement should be taken without first consulting a physician.

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Ginkgo biloba is a plant extract containing several compounds that may have positive effects on cells within the brain and the body. Ginkgo biloba is thought to have both antioxidant and anti-inflammatory properties, to protect cell membranes, and to regulate neurotransmitter function. Ginkgo has been used for centuries in traditional Chinese medicine and currently is being used in Europe to alleviate cognitive symptoms associated with a number of neurological conditions.

In a study published in the Journal of the American Medical Association (October 22/29, 1997), Pierre L. Le Bars, MD, PhD, of the New York Institute for Medical Research, and his colleagues observed in some participants a modest improvement in cognition, activities of daily living (such as eating and dressing), and social behavior. The researchers found no measurable difference in overall impairment.

Results from this study show that ginkgo may help some individuals with Alzheimer’s disease, but further research is needed to determine the exact mechanisms by which Ginkgo works in the body. Also, results from this study are considered preliminary because of the low number of participants, about 200 people. Few side effects are associated with the use of Ginkgo, but it is known to reduce the ability of blood to clot, potentially leading to more serious conditions, such as internal bleeding. This risk may increase if Ginkgo biloba is taken in combination with other blood-thinning drugs, such as aspirin and warfarin.

Currently, a multicenter trial with about 3,000 participants is investigating whether Ginkgo may help prevent or delay the onset of Alzheimer's disease or vascular dementia.

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Huperzine A is a moss extract that has been used in traditional Chinese medicine for centuries. Because it has properties similar to those of FDA-approved Alzheimer's medications, it is promoted as a treatment for Alzheimer's disease.

Evidence from small studies show that the effectiveness of huperzine A may be comparable to that of the approved drugs. Large-scale trials are needed to better understand the effectiveness of this supplement.

Because huperzine A is a dietary supplement, it is unregulated and manufactured with no uniform standards. If used in combination with FDA-approved Alzheimer's drugs, an individual could increase the risks of serious side effects.

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Phosphatidylserine (pronounced FOS-fuh-TIE-dil-sair-een) is a kind of lipid, or fat, that is the primary component of cell membranes of neurons. In Alzheimer's disease and similar disorders, neurons degenerate for reasons that are not yet understood. The strategy behind the possible treatment with phosphatidylserine is to shore up the cell membrane and possibly protect cells from degenerating.

The first clinical trials with phosphatidylserine were conducted with a form derived from the brain cells of cows. Some of these trials had promising results. However, most trials were with small samples of participants.

This line of investigation came to an end in the 1990s over concerns about mad cow disease. There have been some animals studies since then to see whether phosphatidylserine derived from soy may be a potential treatment. A report was published in 2000 about a clinical trial with 18 participants with age-associated memory impairment who were treated with phosphatidylserine. The authors concluded that the results were encouraging but that there would need to be large carefully controlled trials to determine if this could be a viable treatment.

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