Research shows the importance of long-term commitment to the MIND diet for reaping the greatest benefit to brain health.
“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,” said lead study author Lisa Barnes, PhD, associate director of the Alzheimer’s Disease Research Center at RUSH.
Results from the study, published in The New England Journal of Medicine, showed that within a three-year period, there was no significant statistical difference in change in cognition for participants in the MIND diet group compared to the usual diet control group; both groups were coached to reduce calories by 250 kilocalories per day. But there was a significant improvement during the first two years of the study.
“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,” Barnes said. “Both groups lost approximately 5 kilograms over three years, suggesting that it could have been weight loss that benefited cognition in this trial.”
Study tracked 604 participants over three years
The latest trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons, was a randomised, Phase III trial that enrolled 604 people who were overweight and had a suboptimal diet and a family history of Alzheimer’s disease. The trial compared two different diet interventions, both of which included dietary counselling with mild calorie restriction of 250 calories per day for weight loss.
Participants of both groups had individualised diet guidelines developed by dietitians, and they received regular phone and in-person consultations, as well as occasional group sessions over the three-year life of the study. Participants were seen five times during the three years to evaluate their mental abilities, blood pressure, diet, physical activity, health conditions and medication use.
“Both groups of participants got a lot of support and accountability by trained registered dietitians,” said Jennifer Ventrelle, assistant professor in the Departments of Preventive Medicine and Clinical Nutrition and lead dietitian on the MIND diet trial at RUSH.
“The good news is that this helped all participants improve on average, but unfortunately hindered the ability to detect significant differences between the two groups in this relatively short period of time. Current and future research plans to look at people coached to follow the diet in this format compared to individuals following a usual diet in a format closer to usual care such as brief clinical encounters or a self-guided program with less support.”
“By the end of the study, the average weight loss was approximately 5.5% of initial body weight for all participants, exceeding the study target of 3%, the amount recognised as clinically significant to prevent or improve adverse health outcomes,” Ventrelle said.
“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. 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. More research is needed to confirm this.”
“These individuals were healthy at the start of the trial and had no cognitive impairment, and their cognition got slightly better over time,” Barnes said. “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.”
Research: Barnes L, et al. (2023). Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons. New Eng J Med.; doi: 10.1056/NEJMoa2302368.