While everyone may benefit from a healthy diet, those with higher levels of Alzheimer’s-related blood biomarkers may be more likely to benefit from a MIND diet intervention, according to a new study from the MIND trial.
The biomarkers that were found in the participants’ blood measure two specific proteins that are central to Alzheimer’s disease, beta-amyloid (or amyloid-β40) and phosphorylated tau (or p-tau181).
Beta-amyloid develops into sticky plaques that form between nerve cells in the brain and disrupt cell communication. It is thought to be one of the very early features of the disease.
Similarly, phosphorylated tau are proteins that clump together to form tangles and interfere with normal nerve cell processes. Both biomarkers — often referred to as plaques and tangles — are strongly associated with risk of Alzheimer’s disease and dementia.
“In our analysis of data from the MIND trial, we found that the association between the dietary intervention and cognition varied by how much beta-amyloid and phosphorylated tau individuals had in the blood at the start of the study, raising the possibility that the MIND diet may be more beneficial for individuals with higher levels of these blood biomarkers,” said Klodian Dhana, MD, PhD, lead author of the paper and an associate professor in the department of internal medicine.
The study was published in the June print issue of the Journal of Alzheimer’s Disease.
“While the study is limited because the analysis was conducted after data was collected to uncover patterns, these findings may help inform future research exploring the use of biomarkers to better understand individual responses to the MIND diet,” Dhana said.
MIND diet trial primary results
The recent results were pulled from the MIND trial data whose main findings were published in the New England Journal of Medicine in 2023. It was the first randomized clinical trial designed to test the effects of a diet thought to be protective for brain health on the decline of cognitive abilities among a large group of individuals 65 years or older who did not have cognitive impairment. The 2023 study showed improvement in cognition in both the MIND diet intervention and control groups, but the MIND diet intervention group had a slightly better improvement in cognition, although not significantly better. Both groups lost approximately 5 kilograms, or about 11 pounds, over three years, suggesting that it may have been weight loss that benefited cognition.
“Although the MIND diet did not improve cognition significantly more than the control diet overall,” Dhana said, “this study suggests that the cognitive response to the MIND diet may depend on participants’ baseline levels of blood biomarkers.
“Higher baseline levels of amyloid β40 and p-tau181 were associated with cognitive decline over the study period in the control diet group, but not in the MIND diet group.”
Previous research by the late Martha Clare Morris showed that there was a slower rate of decline among those who ate specific foods. Morris was a nutritional epidemiologist at Rush and the original principal investigator of the MIND diet study. The study was funded by a $14.5 million National Institutes of Health grant and involved two clinical sites, Rush in Chicago and Harvard School of Public Health in Boston.
In 2015, Morris and her colleagues at Rush and Harvard University developed the MIND diet — which is short for Mediterranean-DASH Intervention for Neurodegenerative Delay — in preparation for the trial.
The diet is based on the most compelling research on the foods and nutrients that affect brain health. As the name suggests, the MIND diet is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. Both diets have been found to reduce the risk of cardiovascular conditions, such as high blood pressure, diabetes, heart attack and stroke.
In two studies published in 2015, Morris and colleagues found that the MIND diet could slow cognitive decline and lower a person’s risk of developing Alzheimer’s disease significantly, even if the diet was not followed meticulously.
MIND trial tracked 604 participants over three years
The first trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons, was a randomized, Phase III trial that enrolled 604 people with an average age of 70 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 counseling with mild calorie reduction of 250 calories per day for weight loss.
Participants of both groups had individualized 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.
MIND diet food groups
The MIND diet has 14 dietary components, including nine “brain-healthy food groups” — such as chicken and fish, green leafy vegetables and berries, and nuts — and five unhealthy groups: red meat, butter and stick margarine, full fat cheese, pastries and sweets, and fried foods.