Eat Less To Help Prevent Brain Diseases, Study Suggests

In a study of animal models of brain diseases, researchers at the University of Kentucky's Sanders-Brown Center on Aging found they could reduce the effects of experimentally induced injuries to the brain by maintaining rats on reduced diets.

"It's a leap to extrapolate from animal studies to human diseases," said Mark P. Mattson, Ph.D., professor of anatomy and neurobiology at the University of Kentucky, senior author of the report. "However, when you consider these results in light of the evidence that diet reduction reduces risk in humans for cardiovascular diseases and cancer, which involve some of the same cellular mechanisms, it isn't unreasonable to recommend that people reduce food intake as a hedge against neurodegenerative diseases."

Although formal studies of calorie intake and neurodegenerative diseases in humans have not been performed, correlations have been pointed out between the lower caloric intake and lower incidences of Alzheimer's for people in China and Japan compared to the United States and Canada.

In the University of Kentucky study, one group of rats was fed only every other day, consuming 30% fewer calories and weighing 20% less, than a second group whose diet was not restricted. Several months later, the researchers administered toxins that selectively destroy parts of the brain in ways that mimic the destruction wrought by neurodegenerative diseases.

In an experimental model of Alzheimer's disease, the toxin kainic acid was used to damage the hippocampus, a part of the brain involved in learning and memory. In an experimental model of Huntington's disease, the toxin 3-nitropropionic acid was used to damage the striatum, a part of the brain critical for movement.

Scientists are particularly interested in the damage caused to cells by toxins such as kainic acid and 3-nitropropionic acid because it offers clues to the formation of free radicals, molecules that are implicated not only in neurodegenerative diseases and stroke but also in cardiovascular disease and cancer.

The rats whose diets had been restricted were much more resistant to the toxins. Their hippocampal and striatal cells appeared to be buffered from the degeneration that occurred in the corresponding brain areas of the normally fed rats. Similarly, food-restricted rats performed better on learning and memory tests after kainic acid and on movement tests after 3-nitropropionic acid.

Much of the research in age-related neurologic disease is focused on trying to cure or slow down these processes with drugs and other therapeutic approaches. The results of this study, said Mattson, suggest a complementary approach based on educating the public about diet.

Other scientists stress that these data should be viewed cautiously. Until more evidence, especially in humans, becomes available, they feel it is inappropriate to use this study alone to recommend calorie reduction in human diets.

Other authors of the study were Annadora J. Bruce-Keller, PhD, Gloria Umberger, BS, MPH, and Robert McFall, BS, of the University of Kentucky.