Finishing off a juicy steak can be the highlight of your night out, but when that special meal becomes a regular occurrence, you could be harming your brain over the long term.
Previous studies have linked saturated fats in red meat to an increased risk of heart attack, stroke, and death. This type of fat is also in fatty dairy foods like ice cream and whole milk, and packaged foods such as cookies and crackers.
A new study by researchers at Brigham and Women’s Hospital found that these sources of “bad” saturated fats might also affect your brain function, including memory.
Researchers looked at data from 6,000 women over the age of 65 who were part of a larger women’s health study. At the start of the study, they interviewed the women about their diets. Each woman completed three cognitive—mental—function tests over a four-year period, one about every two years.
Total fat intake didn’t affect brain function, but women who ate the most saturated fats had the worst changes in their cognitive function and memory. Women who ate the most monounsaturated fats—such as those found in olive oil, avocados, and nuts—fared the best.
Early declines in brain function and memory can put people at risk of more serious conditions later, such as dementia and Alzheimer’s disease. This study shows that small dietary changes could have a potentially huge impact later on.
“People will want to think about substituting out saturated fat in favor of monounsaturated foods,” study author Dr. Olivia Okereke told Time. “Making that substitution might be a way to prevent cognitive decline in older people.”