Diet helps prevent Alzheimer's

The low-fat, low-glycaemic diet often promoted for general health and well-being may lower the risk of developing Alzheimer's disease if adopted early in life and making a switch to this dietary pattern may provide some benefit to those who are experiencing cognitive difficulty. But starting such an eating plan after symptoms surface doesn't seem to help prevent deterioration of brain function.

Although previous studies have probed connections between lifestyle factors and cognitive ability, there is as yet no clear proof that diet (or much else) can prevent Alzheimer's, the most common form of dementia among the elderly. A low-glycemic diet, which focuses on eating fruits and vegetables, whole grains and lean meats, avoids spikes in blood sugar and is said to promote feelings of fullness.

Older age is the leading known risk factor for Alzheimer's disease. A gene variation is also tied to high risk for the brain disorder. Experts stress that the general public should still focus on avoiding behaviors already linked to other chronic diseases.

The study, conducted in America, looked at the effect of different diets on biomarkers associated with Alzheimer's, such as blood sugar levels, cholesterol and blood lipid levels. The researchers also tested memory after participants followed the assigned diets. Twenty healthy adults and 29 with mild memory problems often considered a precursor to Alzheimer's followed either a high-fat, high simple-carbohydrate diet (HIGH diet) or a diet lower in fat and simple carbohydrates (LOW diet). After four weeks, healthy participants on the LOW diet had changes in biomarkers, including insulin and lipid levels in the blood, which were moving away from those normally associated with dementia. In participants with mild cognitive impairment, this diet had the opposite effect. Additionally, the LOW diet improved performance on delayed visual recall tests for both healthy and memory-impaired participants, but did not affect scores on other cognitive measures. In healthy adults, the HIGH diet moved the biomarkers in a direction that may characterize a presymptomatic stage of Alzheimer's disease.

It, however, remains to be seen if the changes noted in this study actually translate, over the longer term, into differences in risk for developing Alzheimer's disease. The bottom line, though, is the same as it's been for eons: A healthy diet lowers risk of type 2 diabetes, heart disease, cancer and maybe even Alzheimer's. That means staying away as much as possible from processed foods.  The findings may reveal important treatment targets that can be modulated through targeted dietary or drug intervention.