People who eat a diet rich in green leafy vegetables as well as other vegetables, fruits, whole grains, olive oil, beans, nuts and fish may have fewer amyloid plaques and tau tangles in their brains — hallmarks of Alzheimer’s disease — than those who March 8, 2023- According to a study published in its online issue, don’t consume such foods Neurology®Medical Journal of the American Academy of Neurology.
The study examined how closely people follow MIND and the Mediterranean diet. Although similar, the Mediterranean diet recommends eating three or more servings of vegetables, fruit and fish per week while the MIND diet prioritizes leafy greens such as spinach, kale and collard greens along with other vegetables. The Mind Diet prioritizes berries over other fruits and recommends one or more servings of fish per week. Both MIND and the Mediterranean diet recommend wine in moderation.
Although this study shows an association of regular consumption of these foods with fewer Alzheimer’s disease plaques and tangles, it does not establish a cause and effect relationship.
“These results are exciting — in just one case improving people’s dietary habits — such as eating more than six servings of green vegetables per week or not eating fried foods — was associated with fewer amyloid plaques in the brain. About four years younger,” said RUSH University in Chicago, Ph.D. Pooja Aggarwal, author of the study. “Although our research does not prove that a healthy diet results in less accumulation of amyloid plaques in the brain, which are also known to be indicators of Alzheimer’s disease, we do know that there is a relationship and that following MIND and the Mediterranean diet may be a way that people can do Improving their brain health and protecting cognition as they age.”
The study involved 581 people with an average age of 84 at the time of the diet assessment who agreed to donate their brains at the time of death to advance dementia research. Participants completed annual questionnaires about how much they ate food items in different categories.
Participants died an average of seven years after the start of the study. Just before death, 39% of participants were diagnosed with dementia. When examined postmortem, 66% met criteria for Alzheimer’s disease.
At autopsy, researchers examined participants’ brains to determine the amount of amyloid plaques and tau tangles. Both are found in the brains of people with Alzheimer’s disease but can also be found in the brains of older people with normal cognition. The researchers then looked back at the diet questionnaires that were collected during follow-up and determined diet quality for each individual.
For the Mediterranean diet, there were 11 food categories. Participants were given a score from zero to 55, if they followed a diet in these categories: whole grain cereals, fruits, vegetables, legumes, olive oil, fish and potatoes. Those who ate red meat, poultry and full-fat dairy were given lower scores.
For Mind Diet, there were 15 categories. Participants were given a score from zero to 15, one point each for 10 brain-healthy food groups, including green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and wine. They lose one point if they eat more than the recommended amount from five unhealthy food groups, including red meat, butter and margarine, cheese, pastries and sweets, and fried and fast food.
The researchers then divided the participants into three groups for each diet and compared those in the highest group with the lowest group. For the Mediterranean diet, people in the highest group had a mean score of 35 while people in the lowest group had a mean score of 26. For the MIND diet, the highest group mean score was 9 while the lowest group mean score was 6.
After adjusting for age at death, sex, education, total caloric intake and whether people had a gene associated with Alzheimer’s disease risk, the researchers found that those who scored highest for adherence to the Mediterranean diet had an average of plaques and tangles in their brains. Like being 18 years younger than the lowest scoring people. The researchers also found that those who scored the highest for adherence to the MIND diet had a mean plaque and tangle volume 12 years younger than those with the lowest scores.
A MIND diet score one point higher corresponded to a normal plaque amount in participants who were 4.25 years younger.
When looking at single food items, the researchers found that people who ate the most green leafy vegetables, or seven or more servings per week, had brain plaque amounts that were about 19 years younger than those who ate the least. or fewer servings per week.
“Our finding that eating more green vegetables is associated with fewer symptoms of Alzheimer’s disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet,” said Agarwal. “Future studies are needed to further establish our findings.”
A limitation of the study was that the participants were mostly white, non-Hispanic, and elderly so the results may not be generalizable to other populations.
The study was funded by the National Institutes of Health.