CHICAGO — The popular Mediterranean-DASH Intervention for Neurodegenerative Delay diet, better known as the MIND diet, specifically focuses on foods and nutrients beneficial for brain health. Now, a new study shows the diet is reaping benefits with a “short-term” impact on cognition.
Despite the positive short-term outcome, results from a three-year clinical trial may not be as remarkable as previously observed in MIND diet studies.
“The benefits within the new study’s three-year clinical trial weren’t as impressive as we’ve seen with the MIND diet observational studies in the past, but there were improvements in cognition in the short-term, consistent with the longer-term observational data,” says Dr. Lisa Barnes, the study’s lead author and associate director of the Alzheimer’s Disease Research Center at RUSH University Medical Center, in a university release.
The findings show no significant statistical difference in cognitive changes between participants on the MIND diet and those on a control diet. Both groups aimed to reduce their daily caloric intake by 250 kilocalories. Noticeable cognitive improvements, though, were detected in the study’s initial two years.
“What we saw was improvement in cognition in both groups, but the MIND diet intervention group had a slightly better improvement in cognition, although not significantly better,” notes Dr. Barnes. “Both groups lost approximately 5 kilograms over three years, suggesting that it could have been weight loss that benefited cognition in this trial.”
This trial was significant, being the first-of-its-kind to explore the effects of a diet believed to boost brain health on cognitive ability decline in a large group of individuals 65 years and older without any cognitive impairment. Over the past six years, U.S. News & World Report has consistently ranked the MIND diet among the top five diets.
The MIND diet is a blend of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. These diets are known to reduce the risk of various cardiovascular issues, like hypertension and diabetes. The MIND diet centers on foods and nutrients beneficial for brain health, and prior research indicated it could decelerate cognitive decline and substantially reduce Alzheimer’s disease risk, even without strict adherence.
The trial involved 604 participants who were overweight, ate suboptimal diets, and had a family history of Alzheimer’s disease. It examined two different dietary interventions, both with the goal of a 250-calorie reduction per day for weight loss.
Due to the intensive support and monitoring each group received from dietitians, discerning significant differences between the groups in this relatively short timeframe proved challenging.
“By the end of the study, the average weight loss was approximately 5.5 percent of initial body weight for all participants, exceeding the study target of 3 percent, the amount recognized as clinically significant to prevent or improve adverse health outcomes,” says Jennifer Ventrelle, assistant professor in the Departments of Preventive Medicine and Clinical Nutrition and lead dietitian on the MIND diet trial at RUSH.
The improved MIND scores at the study’s conclusion indicate both groups likely experienced cognitive benefits, though further research is required to confirm these findings.
“The average MIND score at the end of three years for the MIND group was 11.0 and 8.3 for the control group, placing both groups in a therapeutic range to slow cognitive decline and lower a risk for Alzheimer’s disease, according to previous studies,” explains Ventrelle. “The significant weight loss and improved MIND scores suggest that the control group also improved their diet and may suggest that following the MIND diet at a score of at least 8.3, coupled with at least a 250 calorie reduction to produce weight loss, may improve cognition.”
The MIND diet includes 14 dietary components, with nine recommended “brain-healthy food groups” such as chicken, fish, green vegetables, berries, and nuts. On the contrary, it advises against five unhealthy groups, including red meat and pastries.
“Randomized trials are gold standards for establishing a cause-and-effect relationship between diet and incidence of Alzheimer’s disease,” says Barnes. “These individuals were healthy at the start of the trial and had no cognitive impairment, and their cognition got slightly better over time. Why there was no difference between the two diet groups at the end of the trial could be a result of many factors including that the control group had a relatively healthy diet. Moving forward, we will look at specific food groups and their associations with biomarkers that were measured in the blood to see if certain nutrients and food groups are more important than others since the two groups were pretty healthy from a dietary perspective at the start.”
The study is published in the journal New England Journal of Medicine.
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