Eating too much salt and failing to exercise may contribute to a higher risk of heart disease, but according to a new study from Canadian researchers, it may also be bad for the brain.
Using data from the Longitudinal Study on Nutrition and Successful Aging, scientists found that eating a high-salt diet and being sedentary was strongly linked with faster cognitive decline in elderly people.
Among 1,262 healthy participants who ranged in age from 67 to 84, those with the highest daily sodium intake (defined as 3,091 mg a day or more) and the lowest levels of exercise were more likely to show declining scores on tests of cognitive function over a three-year period, compared with those who had the lowest salt intake (no more than 2,263 mg/day) and exercised regularly.
The association remained even after the scientists controlled for a variety of lifestyle factors like education level, overall diet and waist circumference.
While the study, which was published in Neurobiology of Aging, wasn’t designed to explain the link, its findings support mounting evidence that poor vascular health — which is associated with high-sodium diets and a lack of exercise — may be related to dementia risk.
Currently, some 4 million Americans suffer from some form of dementia, and that number is expected to rise as baby boomers reach the advanced ages at which dementia typically sets in.
Nutrition experts warn that most of us eat too much salt. The average U.S. adult consumes 3,400 mg each day, significantly more than the U.S. Department of Agriculture’s Dietary Guidelines for Americans recommend: young, healthy adults should cap sodium intake at 2,300 mg per day, while those over age 50 or who suffer from hypertension should get no more than 1,500 mg per day.
Those targets are generally easy to hit by eating healthfully prepared meals and avoiding processed foods, which are typically high in sodium. In addition to lowering salt, the study suggests that exercising is key for brain health.
Reported ABC News:
Although cutting down on salt is a safe move, staying fit might be the more important factor when it comes to protecting cognition with age. In fact, exercise may even counteract any potentially damaging effects sodium may have on the heart and blood vessels.
“People who were physically active were protected, regardless of their sodium intake,” said Dr. Carol Greenwood, one of the study’s authors and a professor of nutrition at the University of Toronto. “What’s important is maintaining the integrity of the cardiovascular system, and the benefits of exercise are going to outweigh any negative effects we see with salt.”
So if you just can’t take the salt shaker off the tabletop, at least spend more time on the treadmill. Both your heart and your brain will thank you.