The MIND diet ― a hybrid of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet ― may slow cognitive decline in elderly adults, according to researchers from Chicago's Rush University Medical Center who developed the MIND diet.
In an observational study, elderly people who rigorously followed the MIND diet were 7.5 years younger cognitively during a period of roughly 5 years than those with the poorest adherence.
"Following the MIND diet may be a way to preserve the brain with age and to prevent dementia," Martha Clare Morris, ScD, a nutritional epidemiologist at Rush University Medical Center, told Medscape Medical News.
The study was published online June 15 in the journalAlzheimer’s and Dementia.
"MIND" is an acronym for Mediterranean-DASH Diet Intervention for Neurodegenerative Delay. Both the Mediterranean and DASH diets have been found to reduce the risk for hypertension, myocardial infarction, and stroke.
"The MIND diet modifies the Mediterranean and DASH diets to highlight the foods and nutrients shown through the scientific literature to be associated with dementia prevention," Dr Morris said in a news release.
The MIND diet has 15 dietary components, including 10 "brain-healthy" food groups and five unhealthy groups (ie, red meat, butter and stick margarine, cheese, pastries and sweets, and fried or fast food).
To stick to the MIND diet, a person has to limit intake of the designated unhealthy foods, especially butter (<1 a="" and="" any="" cheese="" day="" fast="" fat="" food="" for="" fried="" of="" or="" p="" pastries="" serving="" sweets="" tablespoon="" the="" three="" week="" whole="">
As for the brain-healthy foods, a person would need to eat at least three servings of whole grains, a green leafy vegetable, and one other vegetable each day, along with having a glass of wine. They would also need to snack most days on nuts, have beans every other day or so, and eat poultry and berries at least two times a week (berries are the only fruits allowed in the MIND diet) and fish at least once a week.
The researchers assessed cognitive change during a period of 4.7 years in 960 adults (mean age, 81.4 years) in the Rush Memory and Aging Project. "The study was not an intervention. We just observed what foods people consumed and then scored them on how well their diets conformed to the MIND diet," Dr Morris told Medscape Medical News.
The overall rate of change in cognitive score was a decline of 0.8 standardized score units per year. In mixed models adjusted for a variety of relevant factors, including age, sex, education, total energy intake, APOE4 carrier status, and participation in cognitive activities, the MIND diet score was "positively and statistically significantly" associated with slower decline in global cognitive score (β = 0.0092; P < .0001) and with five cognitive domains, especially episodic memory, semantic memory, and perceptual speed, the researchers report.
"The difference in decline rates for being in the top tertile of MIND diet scores versus the lowest was equivalent to being 7.5 years younger in age," they write.
Skip the Diet Wars
Strengths of the current study include the prospective study design with up to 10 years of follow-up, annual assessment of cognitive function using standardized tests, comprehensive assessment of diet using a validated questionnaire, and controlling for key confounding factors. "Another important strength is that the MIND diet score was devised based on expansive reviews of studies relating diet to brain function," Dr Morris and her colleagues say.
The observational nature of the study is the primary limitation, they say. "Replication of these findings in a dietary intervention trial would be required to verify its relevance to brain health," they note.
Commenting on this research, Keith Fargo, PhD, director of scientific programs and outreach at the Alzheimer's Association, said, "I don't think we need to be involved in sort of the diet wars. The take-away in general is that if a person is eating in a manner that is heart healthy, that's probably also going to be brain healthy, because the brain does use so much of the nutrients and the oxygen that are carried in the vascular system, and as you age, if your brain isn't getting enough nutrients and oxygen, it is going to be less likely to be able to deal with other factors that cause Alzheimer's disease or other dementias."
"It's probably not that one diet is going to be the best. It's probably just making sure that you are eating healthy," Dr Fargo said.
The study was funded by the National Institute on Aging. The authors have disclosed no relevant financial relationships.
Alzheimers Dement. Published online June 15, 2015. Abstract1>