Two diets, the Mediterranean and the MIND, based on the consumption of green leafy vegetables and others, fruits, whole grains, olive oil, nuts and fish seem to be related to the lower presence of one of the signs of Alzheimer’s disease, such as tau protein plaques and tau protein tangles in the brain.
However, the authors warn that although their results show an association between the regular consumption of these diets and fewer plaques and tangles characteristic of Alzheimer’s disease, in no case is a cause and effect relationship established.
The study, published in “Neurology”, examined a group of people who followed the MIND and Mediterranean diets. The Mediterranean diet recommends the consumption of vegetables, fruits and three or more servings of fish per week, while the MIND prioritizes green leafy vegetables such as spinach, kale along with other vegetables. The MIND diet also prioritizes berries over other fruits and recommends one or more servings of fish per week. Both MIND and the Mediterranean diet recommend small amounts of wine daily.
“Improvement in people’s diets in just one area, such as eating more than six servings of leafy greens per week or not eating fried foods, was associated with fewer amyloid plaques in the brain, which would be similar to being about four years younger,” says study author Puja Agarwal, of RUSH University in Chicago.
“Although our research does not prove that a healthy diet is responsible for fewer brain deposits of amyloid plaques, we do know that there is a relationship and following the MIND and Mediterranean diets may be a way to maintain brain health and protect cognition as we age.” ».
The study included 581 people with an average age of 84 at the time of the diet evaluation who agreed to donate their brains after death. The participants completed annual questionnaires about their food intake in various categories.
Just before death, 39% of the participants had been diagnosed with dementia. When postmortem brains were examined, 66% met the criteria for Alzheimer’s disease.
At autopsy, the participants’ brains were examined for the number of amyloid plaques and tau tangles. Both are found in the brains of people with Alzheimer’s disease, but they can also be found in the brains of older people with normal cognition.
Those who scored highest on the MIND diet had similar amounts of plaque and tangles as their 12-year-old younger
They then reviewed questionnaires about their diets and ranked the quality of each person’s diet.
For the Mediterranean diet, there were 11 food categories. Participants received a score of zero to 55, with higher scores if they adhered to the diet in these categories: whole grains, fruit, vegetables, legumes, olive oil, fish, and potatoes. They received lower scores if they ate red meat, poultry, and full-fat dairy products.
For the MIND diet, there were 15 categories. People received a score of zero to 15, with one point for each of 10 brain-healthy food groups, including leafy greens, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and wine. In addition, they lost one point if they ate more than the recommended food from five unhealthy food groups, including red meat, butter and margarine, cheese, pastries and sweets, fried foods, and fast food.
Green leafy vegetables (such as spinach and green salad), at least six servings a week.
The rest of the vegetables, at least one a day.
Nuts, five servings (approximately 35 grams each serving) per week
Berries, two or more servings a week
Legumes, at least three servings a week
Whole grains, three or more servings a day
Fish, once a week
Poultry, twice a week
Olive oil, as top oil
After adjusting for age at death, gender, education, total caloric intake and whether people had a gene linked to increased risk of Alzheimer’s disease, the researchers found that those who scored highest for adhering to the Mediterranean diet had average amounts of plaque and tangles in the brain similar to being 18 years younger than people who scored the lowest.
They also found that people who scored the highest for adhering to the MIND diet had similar average amounts of plaque and tangles to those 12 years younger than those who scored the lowest.
Looking at individual components of the diet, the researchers found that people who ate the most leafy green vegetables, or seven or more servings per week, had amounts of plaque in their brains corresponding to being almost 19 years younger than people who ate less – one or fewer servings per week.
“Our finding that eating more leafy green vegetables is itself associated with fewer signs of Alzheimer’s disease in the brain.” is intriguing enough that people consider adding more of these foods to their diet», subroad Agarwal.
One limitation of the study was that the participants were mostly white, non-Hispanic, and older, so the results cannot be generalized to other populations.