Fighting Age-related MEMORY Decline

Prepared Foods, June, 2000 by Elizabeth Mannie

Scientists investigate whether dietary components can reduce age-associated memory impairment

Modest forgetfulness among the elderly is generally considered normal. This age-associated memory impairment (AAMI) can occur when a person is tired, sick, or under stress. It is not progressive or disabling, as are certain types of dementia [1].

Vascular dementia, accounting for 10% to 20% of dementia cases, can result from several small strokes in the brain or from long-term high blood pressure, cardiovascular disease or diabetes. However, preventive measures like weight control, exercise, medications, low salt and lowfat diets can help thwart further deterioration [1].

Alzheimer's Disease (AD) affects three to four million Americans. Of those aged 65 and older, 7% of men and women suffer from AD or other forms of dementia. Estimates indicate that by the middle of this century, the numbers will reach 14 million. Aging baby boomers pose a serious threat to Medicare with the high cost of care to AD patients.

Diet and Cognitive Decline

"People are always interested in dietary habits that can prevent disease such as a lowfat diet preventing heart disease, but at this time there is no major dietary intervention known to prevent AD or memory impairment," says Bill Thies, vice president, Medical and Scientific Affairs at the Alzheimer's Association. "However, a healthy diet allows people to do as well as they can if they contract AD or are a caregiver for someone with the disease."

Dietary components that are associated with improved cognitive functions include:

* Monounsaturated Fatty Acids: Italian researchers and others claim that a diet high in monounsaturated fatty acids (MUFAs), such as those found in olive oil, may help protect against cognitive decline [2]. Higher intakes of MUFAs were associated with better scores on the mini-mental state exam in 278 men and women aged 65 to 84 who did not have dementia. Authors theorized that the antioxidants in olive oil provided the protective effect.

* Vitamin E: Functioning as an antioxidant, vitamin E may aid in the breakdown of free radicals causing damage to tram cells in AD patients. The National Institute on Aging's Memory Impairment Study, one of the first major prevention trials for AD currently being conducted, is designed to test drug interventions in well-functioning people by combining a cholinesterase inhibitor donepezil (Aricept(r)) and vitamin E to investigate their effectiveness in delaying or preventing the onset of AD in individuals with mild cognitive impairment.

An earlier multilocation, double-blind, placebo-controlled study [3] concluded that in patients with moderately severe impairment from AD, treatment with selegiline or [alpha]-tocopherol (vitamin E) slowed the progression of the disease by over 6 months.

"If vitamin E can slow the progression of AD after it is diagnosed, it is very likely that it would have a much stronger effect for prevention if people at risk start taking it early. But it is important to take the complete family of tocopherols plus tocotrienols because they provide a wider spectrum of protection, especially against nitrogen radicals which have been implicated in neurodegenerative diseases like AD," says Andreas M. Papas, Ph.D., author of "The Vitamin E Factor" (HarperCollins, 1999; http://www.vitaniinefactor.com).

* Folic acid: In the Nun Study, low serum folate levels were strongly associated with cerebral cortex atrophy in those with significant Alzheimer lesions in the brain. Folate is important for development of the human nervous system during pregnancy; time will tell whether mandated folic acid fortification will reduce incidence of AD.

* Huperizine A: Dietary supplement huperzine A (hup A) is considered to be as potent as the prescription cholinesterase inhibitors on the market. However, supplements are not yet manufactured under uniform standards, so questions are associated with its use. Derived from the moss of Huperzia serrata, hupA is gaining attention in the U.S.

* Ginkgo biloba: "Western medicine has not widely investigated the pharmacological properties of memory-enhancing plants in current models of AD. An exception is Gingko biloba, in which the gingkolides have antioxidant, neuroprotective and cholinergic activities relevant to AD mechanisms," notes Dr. E.K. Perry, Medical Research Council, Newcastle General Hospital, Newcastle upon Tyne, U.K.

The therapeutic efficacy of Ginkgo extracts in AD in placebo-controlled clinical trials is reportedly similar to currently prescribed drugs and undesirable effects are minimal. Old European reference books on medicinal herbs document a variety of other plants such as Salvia officinalis (sage) and Melissa officinalis (balm) with memory-improving properties, and cholinergic activities have recently been identified in extracts of these plants, Perry notes.

As developed countries rush into the new millenium with rapidly aging populations, interest in memory-enhancing dietary components will no doubt increase as well.