More than just contributing to high obesity rates, diets high in cholesterol and saturated fat can contribute to memory loss as we age.
In a study published in the June issue of the Journal of Alzheimer’s Disease (14(2):133-145), researchers at Medical University of South Carolina, Charleston, and at Arizona State University, Tempe, linked declining working memory in middle-age rodents to a high-fat, high-cholesterol diet.
The memory loss is associated with inflammation in the brain, as well as the impairment of structural proteins that affect how a nerve cell functions. This diet-induced inflammation could also lead to failure of eyesight, hearing and other key functions.
For the study, researchers fed a high-cholesterol (2%) and high-saturated-fat (hydrogenated coconut oil, 10%) diet to 16-month-old rats for 8 weeks. A control group consumed an isocaloric diet (12% soybean oil). Lipid profiles revealed elevated levels of plasma triglycerides and total cholesterol for the cholesterol and saturated fat group compared to the isocaloric control group. Weight increase and food consumption were similar in both groups.
Rats in the cholesterol and saturated fat group committed more working memory errors in a water radial arm maze, especially at higher memory loads. Analysis of rats fed the cholesterol and saturated fat diet indicated a loss of dendritic integrity and inflammation, among other conditions.
Results of the study suggest that—assuming the same phenomenon that occurred in rodents also occurs in humans—as humans age, memory might be preserved and brain functions improved by restricting consumption of cholesterol and saturated fats.