MIND, Mediterranean diets linked to fewer signs of Alzheimer’s disease

Individuals who consumed MIND and Mediterranean diets had fewer amyloid plaques and tau tangles in their brain, which are indicators of Alzheimer’s disease, according to researchers.

“While our research doesn’t prove that a healthy diet resulted in fewer brain deposits of amyloid plaques ... we know there is a relationship and following the MIND and Mediterranean diets may be one way that people can improve their brain health and protect cognition as they age,” Puja Agarwal, PhD, an assistant professor in the department of internal medicine at Rush Medical College, said in a press release.

Agarwal and colleagues examined associations between the two diets — which were previously found to benefit cognitive health in older adults — and amyloid and neurofibrillary tangles, both “important hallmarks” of Alzheimer’s disease, the researchers wrote in Neurology.

“Some researchers have reported that the MIND and Mediterranean diets are positively associated with factors that may partly explain their associations with cognition, such as total brain volume, cortical thickness, and white matter hyperintensity,” they wrote.

The researchers analyzed the prevalence of amyloid plaques and tau tangles during the autopsies of 581 participants who had undergone a dietary assessment prior to death. The participants had a mean age of 84 years at assessment and 91 years at death.

Agarwal and colleagues scored patients’ level of adherence to the diets from:

• zero to 55 total points for the Mediterranean diet; and
• zero to 15 total points for the MIND diet.

Higher scores indicated greater adherence to the diets.

The researchers found that, for the Mediterranean diet, participants in the highest adherence group had an average score of 35 points, while those in the lowest group had an average score of 26 points. For the MIND diet, participants in the highest scoring group had an average score of nine points and the lowest group had an average score of six points.

Overall, higher scores of both the MIND diet (P = .035) and Mediterranean diet (P = .039) were associated with lower global Alzheimer’s disease pathology and a lower beta-amyloid load.

After the researchers adjusted for several factors, including age at death, sex and whether participants had a gene linked to Alzheimer’s disease, they found that those with the highest adherence scores for the Mediterranean diet had plaque and tangle amounts that were similar to being aged 18 years younger than participants with the lowest adherence scores, according to the release. In addition, participants who had the greatest adherence to the MIND diet had average plaque and tangle amounts that were similar to being aged 12 years younger than those with the lowest scores.

Agarwal and colleagues additionally found that a MIND diet score “one point higher corresponded to typical plaque deposition of participants who are 4.25 years younger in age.”

However, they reported that the inverse association between beta-amyloid load and diet adherence was stronger for the Mediterranean diet than the MIND diet.

“Thus, we speculate that the MIND diet, which recommends berries and green leafy vegetables intake, and other important nutrients for brain health may have its relationship with Alzheimer’s disease via unknown mechanisms in addition to beta-amyloid load and needs further investigation,” they wrote.

The study was limited due to the possibility that cognitive decline altered dietary patterns, according to the researchers. In addition, there was an underrepresentation of diverse populations.

“Our finding that eating more green leafy vegetables is in itself associated with fewer signs of Alzheimer’s disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet,” Agarwal said in the release.

References:

• MIND and Mediterranean diets associated with fewer Alzheimer’s plaques and tangles. https://www.newswise.com/articles/mind-and-mediterranean-diets-associated-with-fewer-alzheimer-s-plaques-and-tangles. Published March 8, 2023. Accessed March 8, 2023.
• Agarwhal P, et al. Neurology. 2023;doi:10.1212/WNL.0000000000207176.