Could a Healthy Diet Lower Risk of Cognitive Decline?
Healthier eating may be linked to stronger cognitive health later in life, according to a study in the journal Neurology.
Researchers followed nearly 28,000 people for an average of 5 years, monitoring their diets, and testing declines in thinking and memory tests. Hailing from 40 different countries across the globe, all of the participants were ages 55 and older.
Those who reported eating the healthiest diets showed a lower likelihood of having a drop in thinking and memory.
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“Rather than focus on the intake of any specific food or nutrient, or a particular diet pattern, our study shows that higher diet quality is associated with a reduced risk of cognitive decline,” says lead study author Andrew Smyth, MMedSc, of McMaster University in Hamilton, Ontario, Canada, and the National University of Ireland in Galway.
The healthy diet associated with stronger cognitive health included lots of fruits and vegetables, nuts, and fish, a moderate amount of alcohol, and not much red meat.
“We chose this approach instead of focusing on any particular food, as foods are not consumed in isolation and changes in the intake of one particular food will likely result in an increase or decrease in the intake of other foods,” he explains. “In addition, different people consume particular foods differently—for example, fresh fruit vs. cooked/stewed fruits, fresh/raw vegetables vs. steamed vegetables vs. fried vegetables.”
Smyth says there are a few possible mechanisms that may account for the association between healthy diet and reduced risk of cognitive decline:
• “People who consume healthy diets often have healthy lifestyles in general (e.g. less likely to smoke, more likely to be active, etc.),” he says. He and his colleagues controlled for these factors in their statistical analyses but cannot be certain that some of the effect wasn’t due to a healthy lifestyle overall.
• “A healthy diet is associated with a reduction in cardiovascular events (including overt and covert stroke), so the reduction in cognitive decline may be due to reduction in cardiovascular risk and events,” he says. The team conducted an additional analysis where they excluded people who had new strokes or heart attacks during the study follow-up, and showed a similar association.
• “A healthy diet often includes the intake of foods rich in omega-3 fatty acids, vitamin C, vitamin E, folate, and other agents that may have effects on inflammatory pathways that may reduce tissue damage,” he says.
Smyth and his colleagues concluded that improved diet quality could offer an important potential target for reducing the global burden of cognitive decline. He plans to continue studying the association between modifiable lifestyle factors, such as diet, and non-communicable disease, including heart disease, stroke, kidney function, cognitive function, and overall functional status.
—Colleen Mullarkey
Reference
Smyth A, Dehghan M, O’Donnell M, Anderson C, Teo K, Gao P, et al. Healthy eating and reduced risk of cognitive decline: A cohort from 40 countries. Neurology. 6 May 2015. [epub ahead of print].