That bacon double cheeseburger may be as bad for your brain
as it is for your heart. A recent study in Annals of Neurology found a link
between heart-unhealthy saturated fat and worsening mental test scores in older
women over time. In fact, a diet high in saturated fat seemed to speed up
mental decline by five to six years, compared to a diet low in this kind of
The study was led by Olivia Okereke, MD, an assistant
professor of psychiatry and epidemiology at Harvard. It was based on data from more
than 6,000 women over age 65.
Researchers identified a group of women who had the greatest
mental decline during the four-year study period. Women with the highest intake
of saturated fat were 60 to 70 percent more likely to be in this group, compared to
those with the lowest saturated fat intake. Foods laden with saturated fat
include fatty beef and pork, poultry with skin, butter, whole milk, and
Scientists are still studying how dietary fat affects brain function.
But it’s known that a diet high in saturated fat can contribute to heart and
blood vessel disease. And that, in turn, can restrict the brain’s blood supply,
making it harder for brain cells to get all the oxygen and nutrients they need.
Heart health guidelines recommend replacing saturated fat
with moderate amounts of a good-for-you alternative, such as monounsaturated
fat—the type found in olive oil. Monounsaturated fat helps fight high
cholesterol and lowers the risk for heart disease. Based on the new study, shifting
your diet in this direction could be smart for your brain as well.
Women in the study with the highest intake of monounsaturated
fat were 40 to 50 percent less likely to be
in the greatest mental decline group, compared to those with the lowest
monounsaturated fat intake. In addition to olive oil, foods rich in this type
of fat include canola oil, peanut oil, sunflower oil, and sesame oil. Other
sources include avocados, peanut butter, and many nuts and seeds.
As people get older, many notice that they’ve become a little
more forgetful or that it takes a bit longer to remember names. But for some,
the changes grow more pronounced. When thinking ability and memory slip enough
to be an increasing concern, but not enough to limit day-to-day activities, a
person may have mild cognitive impairment. This condition can be worrisome in
itself. But the biggest issue is that it can be an intermediate step between
normal aging and Alzheimer’s disease.
There’s not enough evidence yet to say conclusively that limiting
saturated fat helps prevent or delay mild cognitive impairment. But research
suggests that it might. And what have you got to lose? Replacing saturated fat with
a healthier fat helps protect your heart. If it helps keep your brain younger,
too, that’s a two-for-one deal you don’t want to pass up.