While it’s no secret that eating too many foods containing bad fats—saturated fats (primarily animal fats) and trans fats (hydrogenated oils and the processed foods that contain them), is bad for for your heart. Now we’re learning that saturated fat is associated with worse overall cognitive function and memory in women over time. By contrast, a "good" fat—mono-unsaturated fat, found in certain vegetable oils—was associated with better overall cognitive function and memory.
In a study from Brigham and Women's Hospital published online by Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society, researchers analyzed data from the Women's Health Study, which originally involved nearly 40,000 women, age 45 and older. For this study, researchers focused on data from a subset of 6,000 women, all over age 65. The women participated in three cognitive function tests, which were spaced out every two years, for an average testing span of four years, filling out very detailed food frequency surveys at the start of the Women's Health Study, prior to the cognitive testing. "When looking at changes in cognitive function, what we found is that the total amount of fat intake did not really matter, but the type of fat did," explained Olivia Okereke, MD, MS, BWH Department of Psychiatry. Compared to women who ate the lowest amounts of saturated fat—such as red meat, cream, full-fat dairy and butter, the women who ate the highest amounts had worse overall cognition and memory over the four years of testing. Women who ate the most of the monounsaturated fats, which can be found in olive oil, had better patterns of cognitive scores over time.
"Our findings have significant public health implications," said Okereke. "Substituting in the good fat in place of the bad fat is a fairly simple dietary modification that could help prevent decline in memory." Okereke notes that strategies to prevent cognitive decline in older people are particularly important. Even subtle declines in cognitive functioning can lead to higher risk of developing more serious problems, like dementia and Alzheimer disease.