A new diet known by the acronym MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) could significantly lower a person’s risk of developing Alzheimer’s disease (AD) — even if the diet is not meticulously followed, according to a paper published in the journal Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
This finding comes from a longitudinal study by Rush University Medical Center and Harvard School of Public Health of 923 volunteers (144 of them developed Alzheimer’s Disease) shows that the MIND diet lowered the risk of Alzheimer’s Disease by as much as 53 percent in participants who adhered to the diet rigorously, and by about 35 percent in those who followed it moderately well.
Developed by nutritional epidemiologist Martha Clare Morris, PhD, and colleagues at Rush University Medical Center in Chicago, the MIND diet is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets, both of which have been found to reduce the risk of cardiovascular conditions, like hypertension, heart attack, and stroke. Some researchers have found that these two older diets provide protection against dementia as well.
Morris and her colleagues developed the MIND diet based on information that has accrued from years’ worth of past research about what foods and nutrients have good, and bad, effects on the functioning of the brain over time. This is the first study to relate the MIND diet to Alzheimer’s disease.
Easier to follow than the Mediterranean diet
In the latest study, the MIND diet was compared with the two earlier diets. People with high adherence to the DASH and Mediterranean diets also had reductions in AD — 39 percent with the DASH diet and 54 percent with the Mediterranean diet — but got negligible benefits from moderate adherence to either of the two other diets.
The MIND diet is also easier to follow than, say, the Mediterranean diet, which calls for daily consumption of fish and three to four daily servings of each of fruits and vegetables, Morris said.
The MIND diet has 15 dietary components, including 10 “brain-healthy food groups” — green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and wine — and (because it was tracking what people actually eat, rather than what they should) five unhealthy groups that comprise red meats, butter and stick margarine, cheese, pastries and sweets, and fried or fast food.
The MIND diet includes at least three servings of whole grains, a salad and one other vegetable every day — along with a glass of wine. It also involves snacking most days on nuts and eating beans every other day or so, poultry and berries at least twice a week and fish at least once a week. Dieters must limit eating the designated unhealthy foods, especially butter (less than 1 tablespoon a day), cheese, and fried or fast food (less than a serving a week for any of the three), to have a real shot at avoiding the devastating effects of Alzheimer’s, according to the study.
Berries are the only fruit specifically to make the MIND diet. “Blueberries are one of the more potent foods in terms of protecting the brain,” Morris said, and strawberries have also performed well in past studies of the effect of food on cognitive function.
Participants in study were assigned points if they ate brain-healthy foods frequently and avoided unhealthy foods. The one exception was that participants got one point if they said olive oil was the primary oil used in their homes.
The study enlisted volunteers already participating in the ongoing Rush Memory and Aging Project (MAP), which began in 1997 among residents of Chicago-area retirement communities and senior public housing complexes. An optional “food frequency questionnaire” was added from 2004 to February 2013.
Food more important than genetic risk factors
“With late-onset AD, with that older group of people, genetic risk factors are a small piece of the picture,” she said. Past studies have yielded evidence that suggests that what we eat may play a significant role in determining who gets AD and who doesn’t, Morris said.
When the researchers in the new study left out of the analyses those participants who changed their diets somewhere along the line — say, on a doctor’s orders after a stroke — they found that “the association became stronger between the MIND diet and [favorable] outcomes” in terms of AD, Morris said. “That probably means that people who eat this diet consistently over the years get the best protection.”
In other words, it looks like the longer a person eats the MIND diet, the less risk that person will have of developing AD, Morris said. As is the case with many health-related habits, including physical exercise, she said, “You’ll be healthier if you’ve been doing the right thing for a long time.”
Morris said, “We devised a diet and it worked in this Chicago study. The results need to be confirmed by other investigators in different populations and also through randomized trials.” That is the best way to establish a cause-and-effect relationship between the MIND diet and reductions in the incidence of Alzheimer’s disease, she said.
The study was funded by the National Institute on Aging.
Abstract of MIND diet associated with reduced incidence of Alzheimer’s disease
Background: In a previous study, higher concordance to the MIND diet, a hybrid Mediterranean- Dietary Approaches to Stop Hypertension diet, was associated with slower cognitive decline. In this study we related these three dietary patterns to incident Alzheimer’s disease (AD).
Methods: We investigated the diet-AD relations in a prospective study of 923 participants, ages 58 to 98 years, followed on average 4.5 years. Diet was assessed by a semiquantitative food frequency questionnaire.
Results: In adjusted proportional hazards models, the second (hazards ratio or HR 5 0.65, 95% confidence interval or CI 0.44, 0.98) and highest tertiles (HR 5 0.47, 95% CI 0.26, 0.76) of MIND diet scores had lower rates of AD versus tertile 1, whereas only the third tertiles of the DASH (HR 5 0.61, 95% CI 0.38, 0.97) and Mediterranean (HR 5 0.46, 95% CI 0.26, 0.79) diets were associated with lower AD rates.
Conclusion: High adherence to all three diets may reduce AD risk. Moderate adherence to the MIND diet may also decrease AD risk.