MedicalResearch.com Interview with:
William B. Grant, Ph.D.
Director, Sunlight, Nutrition, and Health Research Center
San Francisco, CA
www.sunarc.org
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The present study is the culmination of 20 years of investigating dietary links to Alzheimer's disease (AD). I am a physicist by training and spent my salaried career as an atmospheric scientist. In the 1990s while studying the effect of acid rain and ozone on eastern hardwood forests, I became familiar with the geographical ecological study approach. In this approach, populations are defined geographically, such as by state or country, and health outcomes are compared statistically with risk-modifying factors. Ecological studies are an efficient way to analyze the results of unplanned experiments.
In 1996, I read that Japanese-American men living in Hawaii had two and a half times the prevalence of Alzheimer's disease as native Japanese. I knew that AD patients often had higher concentrations of aluminum in their brains than other people, and that acid rain increased the concentration of aluminum in trees. It quickly occurred to me that the American diet must be the cause of the increased AD rate, and that by using the ecological approach, I could prove it. My first study, published in 1997, compared AD prevalence rates for 11 countries with macro-dietary factors of national diets. Total fat was found to have the highest correlation with AD, followed by total energy (calories), with fish reducing risk slightly, while countries such as China, Japan, and India, with large amounts of rice in the diet, had very low Alzheimer's disease rates. This study was the first major study linking diet to risk of AD and led to observational studies that confirmed the findings five years later.
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