From time to time, we all like to sink our teeth into a gooey cheese pizza or chocolaty cookie, or sip on a frothy milkshake. But even a single such indulgence can have a negative impact on our brain, according to a recent study.
Researchers found that eating a single high-fat meal can inhibit the flow of blood to the brain. If this happens often enough over time, it could increase the risk of brain conditions like stroke or dementia, they say.
For the study, the researchers enlisted 20 men between the ages of 18 and 35 and 21 men between the ages of 60 and 80.
Participants were given a milkshake containing 130 grams of fat (most of which was from saturated fat) and 1,362 calories. It was intended to mimic a fast-food meal.
The researchers measured how well the participants’ blood vessels linked to heart and brain health functioned before they drank the milkshake and for four hours after.
Participants were also asked to perform squats. The goal was to determine how effectively the brain could manage swings in blood pressure — such as happen when you stand up — after a high-fat meal.
Ultrasound testing was used to determine how blood flowed through vessels.
The researchers found that in both the younger and older participants, the high-fat meal reduced the ability of blood vessels to open for several hours. That in turn lowered the brain’s ability to buffer changes in blood pressure. The impact was about 10% worse in the older men.
In an article about the study’s findings, two of the researchers, both of the University of South Wales in the United Kingdom, write:
“Although we didn’t directly test for the long-term effects of a high-fat meal on mental functioning in this study, we have previously shown that such a meal increases free radicals (unstable, cell-damaging molecules) and decreases nitric oxide (molecules that help blood vessels relax and open up to transport oxygen and glucose around the body).”
The researchers say this may account for the impaired blood flow they observed.
The study findings were published in a scientific journal of the Physiological Society.
It is well-known that eating a meal high in saturated fat causes levels of fat to increase in the blood. The process peaks after about four hours and causes blood vessels to stiffen, restricting blood flow throughout the body.
But prior to the study led by the University of South Wales researchers, little was known about how these changes impact the brain, or how well the brain’s blood supply was protected.
The study findings underscore the importance of eating a diet low in saturated fat as a means of protecting both the heart and the brain, the researchers say.
They add that this is even more important for older adults, who may be more vulnerable to the negative impact of high-fat diets and who are naturally at a higher risk of stroke and neurodegenerative diseases like dementia compared to younger people.
The American Heart Association recommends that people consume no more than 13 grams of saturated fat per day.
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