Diet and cognitive decline

Scientists from the Harvard School of Public Health and Rush University Medical Center performed a landmark study to determine if a Mediterranean-style diet could protect people against cognitive decline. (Short answer: No.) The study, called the MIND Diet Trial, was considered “landmark” because the researchers used the “gold standard” of research: the randomized controlled trial. Because such trials are expensive and take a lot of time, they’re rarely undertaken for nutrition studies. (Most nutrition studies are “observational” and thus not trustworthy.)

After screening 1,929 people, researchers selected 604 older adults who were either overweight or obese, whose diets were “suboptimal,” and who had a family history of dementia, putting them at a high risk for the disease. The participants—none of whom had dementia—were divided into two groups: one who ate a MIND diet with “mild caloric restriction,” and one who ate their normal diets, but also with caloric restriction. At the beginning of the trial, all participants were given cognitive assessment tests and brain scans.

As you’d probably guess, the MIND diet consists of whole grains, leafy green vegetables, nuts, beans, berries, occasional poultry and fish, and olive oil. Specifically, it calls for at least six servings of leafy greens and two servings of berries each week. It restricts pastries, sweets, red meat, cheese, and fried foods to less than one serving a week, and limits butter to less than a tablespoon a day.

The trial lasted for three years, at the end of which participants were again given cognitive assessment tests and brain scans. As reported in The New England Journal of Medicine, outcomes “did not differ significantly between those who followed the MIND diet and those who followed the control diet….”

Perversely, this outcome pleases me. I get so tired of the sanctimonious advice-givers touting the Mediterranean diet. Bring on the cheese and butter! 

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