Diet Affects Markers of Alzheimer's Disease
Low-Fat, Low-Glycemic-Index Diets Improve Markers for Alzheimer’s Disease, Study Suggests
Eating a low-fat, low-glycemic-index diet, on the other hand, lowered levels of beta-amyloid in healthy adults and improved other markers of inflammation and damage in both groups.
What’s more, people who were already showing signs of Alzheimer’s appeared to be even more sensitive to the diets. They saw blood levels of total cholesterol rise nearly twice as much as those of healthy adults on a high-fat, high-glycemic-index diet.
For both groups, the low-fat, low-glycemic-index diet also improved delayed visual memory, which is the ability to remember and recognize complex patterns.
The study is published in the Archives of Neurology.
“We are getting closer to the day where we might give someone an anti-Alzheimer's diet prescription, but we are not there yet,” says P. Murali Doraiswamy, MD, professor of psychiatry and head of the division of biological psychiatry at the Duke University Medical Center in Durham, N.C.
Studies in animals that have been bred to develop brain changes similar to the kind that occur in Alzheimer’s show that high-fat diets can accelerate the disease, says Doraiswamy, who was not involved in the research. “This is the first randomized trial to test that in humans at risk for Alzheimer's,” he says.
But he also cautions that with just 49 participants, “the study is too small to draw any firm conclusions.”
But he said it should inspire a larger, longer-term study that could provide more definitive results.
Tracking the Influence of Diet on Alzheimer’s
For the study, researchers recruited 49 older adults. Twenty of the participants were healthy and showed no intellectual or memory declines. Twenty-nine had been diagnosed with mild cognitive impairment, a condition that’s thought to be early-stage Alzheimer’s disease.
None of the participants had histories of major mental illnesses, alcoholism, neurologic disorders, diabetes, liver or kidney disease, COPD, or unstable coronary artery disease. None was taking medications to lower cholesterol.
The average age of adults in the healthy control group was 69. Those with mild cognitive impairment were slightly younger, about 67 years old, on average.
Before the study, participants took a battery of tests designed to test how quickly their brains worked and how well they were able to remember things.