Drinking fruit and vegetable juices frequently may delay the onset of Alzheimer's disease. In a study published in the September issue of The American Journal of Medicine, researchers followed almost 2000 subjects for up to 10 years and found that the risk for developing Alzheimer's disease was reduced by 76% for those who drank fruit and vegetable juices more than 3 times per week compared with those who drank juices less than once per week. A lower reduction (16%) was obtained for juice consumption once or twice per week.

Recent studies of Alzheimer's disease biochemistry have focused on the accumulation of beta-amyloid peptide in the brain, and the action of hydrogen peroxide in mediating this process. Various studies have suggested that polyphenols, strong anti-oxidants available in many foods, might disrupt these processes and provide some protection against Alzheimer's disease. Although some studies of anti-oxidant vitamins have been disappointing, this study is the first to examine juices rich in polyphenols as a preventive measure for Alzheimer's disease.

The subjects were already part of the Kame Project, a prospective study of Japanese populations living in Hiroshima, Japan; Oahu, Hawaii; and the metropolitan area of Seattle, Washington. Drawing from the Seattle population, 1836 people were identified as free of dementia in 1992-1994, and were followed at 2-year time intervals until the end of 2001. Dietary consumption of fruit and vegetable juices was determined from self-administered questionnaires developed for Asian populations. Cognitive function was assessed by trained interviewers using a standardized test, with clinical follow-up resulting in clinical diagnoses for those patients showing impairment.

Writing in the article, Qi Dai, MD, PhD, states, "We found that frequent drinking of fruit and vegetable juices was associated with a substantially decreased risk of Alzheimer's disease. This inverse association was stronger after adjustments for potential confounding factors, and the association was evident in all strata of selected variables. These findings are new and suggest that fruit and vegetable juices may play an important role in delaying the onset of Alzheimer's disease". Qi Dai also said that the next step is to investigate whether high blood concentrations of polyphenols high in major fruit and vegetable juices are associated with a reduced risk of cognitive decline and Alzheimer's disease.

The study is "Fruit and Vegetable Juices and Alzheimer's Disease: The Kame Project" by Qi Dai, MD, PhD, Amy R. Borenstein, PhD, Yougui Wu, PhD, James C. Jackson, PhD, and Eric B. Larson, MD, MPH, and comes from the Vanderbilt School of Medicine, the Veterans Administration Tennessee Valley Geriatric Research, Education, and Clinical Center, the University of South Florida, Tampa, Florida, and the Group Health Cooperative, Seattle, Washington.

Aug. 31, 2006 - News in Today's Dietitian