A diet rich in certain foods such as nuts, fish, and vegetables and low in high-fat dairy foods and red meat appears to exert a preventive effect on the development of Alzheimer's disease, according to a study.
“Our findings provide support for further exploration of food-combination–based dietary behavior for the prevention of this important public health problem,” wrote Yian Gu, Ph.D., of the Taub Institute for Research in Alzheimer's Disease and the Aging Brain at Columbia University, New York, and associates.
The researchers sought to assess food combinations rather than individual nutrients in relation to Alzheimer's risk, so they studied dietary data obtained by food frequency questionnaires in two multiethnic cohorts: elderly subjects participating in the 1992 and the 1999 Washington Heights–Inwood Columbia Aging Project (WHICAP). Their study included 2,148 individuals who underwent serial batteries of neuropsychological tests, assessments of social and occupational function, and specific testing for cognitive deficits and dementia.
During an average follow-up of 4 years, 253 of these subjects developed Alzheimer's. Subjects were diagnosed for dementia with criteria developed by the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer Disease and Related Disorders Association. Some of the patients also may have had a stroke.
The investigators calculated dietary patterns based on variations in the content of seven key nutrients that have been most consistently related to dementia risk in the literature. Only one dietary pattern was found to be strongly associated with AD prevention: a diet rich in omega-3 polyunsaturated fatty acids, omega-6 polyunsaturated fatty acids, vitamin E, and folate and poor in saturated fatty acids and vitamin B12.
This pattern correlated with high intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous and dark leafy green vegetables, and low intakes of high-fat dairy foods such as butter, red meats, and organ meats, Dr. Gu and colleagues said (Arch. Neurol. 2010 April 12 [doi:10.1001/archneurol.2010.84]).
The protective effect of such a diet did not change after the data were adjusted to account for age, level of education, ethnicity, and sex. Further analysis adjusting for smoking status, body mass index, caloric intake, comorbidities, and apolipoprotein E genotype only slightly attenuated the results. Similarly, adding data on alcohol consumption and use of nutritional supplements did not substantially change the association between this dietary pattern and lower risk of AD. The results were “essentially unchanged” when the analysis was repeated in the subgroup of subjects who developed AD without concomitant stroke.
The study was limited by the use of a single measurement of diet that did not capture long-term dietary habits.
Disclosures: This study was funded by the National Institute on Aging. No financial conflicts of interest were reported.