Eating these foods might protect against cognitive decline, study finds

An apple a day keeps the doctor away but recent research suggests it might also lower your risk for cognitive decline.

Researchers found that people who had a diet high in flavonoids, natural substances in plants that give them their colors, might have a 20% lower risk of cognitive decline compared to people with a diet low in flavonoids.

“There is mounting evidence suggesting flavonoids are powerhouses when it comes to preventing your thinking skills from declining as you get older,” said study author Walter Willett, MD, DrPH, of Harvard University in a statement released by the American Academy of Neurology. “Our results are exciting because they show that making simple changes to your diet could help prevent cognitive decline.”

To reach their conclusion, the researchers analyzed questionnaires where study participants recorded how often they consumed a standard portion size of various foods over the previous year. The nearly 75,000 participants had completed the questionnaire multiple times over the study’s 20 year length.

The researchers also had participants complete questionnaires to determine cognitive decline twice over the 20 year period. The questionnaires included yes or no questions like “Do you have more trouble than usual remembering a short list of items, such as a shopping list?”

“The people in our study who did the best over time ate an average of at least half a serving per day of foods like orange juice, oranges, peppers, celery, grapefruits, grapefruit juice, apples and pears,” Willett said in the statement. “While it is possible other phytochemicals are at work here, a colorful diet rich in flavonoids—and specifically flavones and anthocyanins—seems to be a good bet for promoting long-term brain health.”

The study also found that some foods were associated with a greater reduction in risk than others. For example eating yellow and orange fruits and vegetables containing flavones were associated with a 38% reduction in risk for cognitive decline while eating fruits like blueberries, blackberries, and cherries that contain anthocyanins were associated with a 24% reduced risk of cognitive decline.

The results were similar to a 2020 study of over 2,800 people that found people who consumed high amounts of flavonoid-rich foods were 50% less likely to develop Alzheimer’s disease and related dementias.

“When we look at the study results, we see that the people who may benefit the most from consuming more flavonoids are people at the lowest levels of intake, and it doesn’t take much to improve levels. A cup of tea a day or some berries two or three times a week would be adequate,” Esra Shishtar, who at the time of that study was a doctoral student at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, said in a 2020 statement released by Tufts University.

“The study provides more proof of how the power of plants and produce is so important in our daily diets, and how it can be beneficial nutritionally and possibly protect your mental health,” Karen Blakeslee, a food scientist at Kansas State University who not involved in the study said in a statement.

According to a 2021 report by the Alzheimer’s Association, an estimated 6.2 million people in the United States age 65 or older are living with the disease. By 2050, that number is estimated to double.

“If it is possible to reduce risks of chronic illness with food, why not add these to our diet?” Blakeslee said in a statement.

Both studies however were observational in that researchers did not change the participant’s diets during the study. Instead, they only observed what participants recorded through their questionnaires and whether they developed cognitive decline or Alzheimer’s disease and related dementias during the course of the study.

Nevertheless, the authors still observed benefits regardless of when participants began consuming more flavonoids.

“It’s never too late to start, because we saw those protective relationships whether people were consuming the flavonoids in their diet 20 years ago, or if they started incorporating them more recently,” Willett said in a statement.

This story was originally published August 17, 2021 at 4:09 AM.