Two Diets Found to Reduce Hallmarks of Alzheimer’s Disease in the Brain

What we eat can have a big impact on our health, including our brain health. Foods that have been linked with brain benefits include leafy greens, fatty fish, berries, and walnuts. Maybe unsurprisingly, a new study finds diets that focus on such foods may help reduce signs of Alzheimer’s in the brain… and slow its aging.

Researchers at RUSH University recently investigated the impact of their own MIND diet and the Mediterranean diet on the brains of older adults, finding that both were linked with fewer amyloid plaques and neurofibrillary tangles, hallmarks of Alzheimer’s disease. The study, published in the journal Neurology, also found that people who stuck to these diets the most had younger brains on average. This adds further evidence to the idea that certain foods can help the brain.

Study author Dr. Puja Agarwal says, “These results are exciting. Improvement in people’s diets in just one area — such as eating more than six servings of green leafy vegetables per week, or not eating fried foods — was associated with fewer amyloid plaques in the brain similar to being about four years younger.”

Agarwal adds that though the study doesn’t prove the diets directly cause these brain benefits, there is still an established link, meaning that following these diets may serve as one way to help keep your brain sharp as you age.

The Mediterranean diet focuses on plant-based foods and healthy fats. Staples include extra virgin olive oil, fish with omega-3 fatty acids, whole grains, fruits, veggies, beans, lentils, and nuts. It also limits meat, sweets, and butter.

The MIND diet is similar, promoting 10 brain-healthy foods: leafy greens, other veggies, berries, nuts, beans, whole grains, fish, poultry, olive oil, and small amounts of wine. It also identifies five unhealthy foods to limit, including butter and stick margarine, cheese, sweets, and fried or fast food.

To study the impacts of these diets on the brain, the team used data from participants in the long-term RUSH Memory and Aging Project, which includes residents living in Chicago-area retirement communities and senior public housing. For this study, the researchers included 581 people with an average age of 84 who had filled out annual questionnaires about their diets. On average, they lived for another seven years after this study began. Just before death, 39% had been diagnosed with dementia, with two-thirds meeting the criteria for Alzheimer’s.

The participants were given a point for every brain-healthy food they ate, while they lost a point for each unhealthy food. They were then divided into three groups for each diet. The group with the best adherence to the Mediterranean diet had an average score of 35, while the group with the lowest adherence had a 26. For the MIND diet, the top group had an average score of 9, while the bottom group averaged a 6. The brains of those in the top groups were compared to those in the lowest groups.

The researchers found that, after adjusting for possible confounding factors, those who had the highest adherence to the Mediterranean diet had average amyloid plaque and neurofibrillary tangle amounts of a person 18 years younger than those with the lowest scores. For the MIND diet, the split was about a 12 year difference between the two groups.

The team also found that one particular type of food had the strongest benefit. Those who ate the most leafy greens – seven or more servings per week – had plaque amounts of a brain nearly 19 years younger than those who ate little or no leafy greens.

Agarwal says, “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. Future studies are needed to establish our findings further.”

Though further study is needed, the results are similar to other research on the topic. One recent study found that middle-aged people who regularly eat healthy foods, similar to those in this study, have more gray matter and a higher brain volume. Meanwhile, other research has linked a long-term high-fat diet with cognitive issues.