There are many good reasons for eating less fat, but researchers at the Medical University of South Carolina have come up with an especially memorable one. Their study, published recently in the Journal of Alzheimer’s Disease, links cholesterol and saturated fats with a form of memory loss.
The study, conducted by Lotta Granholm-Bentley, DDS, PhD, and her team in the department of neurosciences and the Center on Aging at MUSC, fed 16-month-old laboratory rats a diet in which 12% of their calories came from fats. One group received 10% of saturated fat and 2% cholesterol, while the other received 12% fats, mostly polyunsaturated and monounsaturated fats and no cholesterol. Rats in both groups ate comparable amounts of food and gained similar weight during their eight weeks on the specialized diet.
During the study, both groups of rats were tested on how well they remembered how to negotiate a series of mazes. The animals eating the bad fats made more mistakes, especially as the maze tasks became more complex. In addition, the animals in the saturated fat-cholesterol group were found to have significantly altered structure in the hippocampus in the temporal lobe compared with those that ate the low saturated fat, no cholesterol diet. Also the rats on bad fats had both fewer and weaker nerve cells in this area of the brain.
The hippocampus is the brain’s spatial memory center, Dr. Granholm-Bentley explains, noting that the bad-fat rats had the type of memory impairment that can be compared to deficits seen in Alzheimer’s patients. “In rats, these skills are important for staying alive in their natural environment, while in humans, they’re what allow us to find the way to the grocery store or remember where we live,” she explained.
Dr. Granholm-Bentley and her colleagues are continuing to study the effects of specific types of fats on memory. In the meantime, she warns that the rats consumed a proportion of fat well below the average 36% of fat that many people eat. Translated to a human timetable, she says that researchers see that memory loss can occur within just a few years — and they hope the reverse proves true, too. “We hope we’ll find that some of the memory damage can be reversed through eating a better diet,” she said. But remember, we all need some fat and cholesterol for optimal health, so don’t go overboard and omit all fat from your diet.
