Diets rich in flavonoids associated with better brain health
Q: Of the nutrients in plant foods, it seems flavonoids may be special for brain health. What do we know?
A: Science is already touting the heart health benefits of plant-based diets like the Mediterranean, MIND, and DASH diets. Researchers are discovering how a plant-based diet can also play an important role in cognitive health and possibly help prevent dementia, including Alzheimer’s disease.
And one class of nutrients in plants continues to stand out: flavonoids. They have six subclasses: anthocyanidins, flavan-3-ols, flavanones, flavones, flavonols and polymers. A variety of fruits and vegetables contain flavonoids. Some of the highest amounts are found in berries, apples, citrus fruits (oranges, lemons), grapes, spinach, legumes, kale, broccoli, soybeans, onions, tea, cocoa and wine. Some foods contain only one subclass of flavonoids, while others have several.
Researchers believe that flavonoids can help the brain in several ways. For example, studies suggest that they reduce free radicals that damage cells and soothe inflammation. Some early-stage animal studies have shown that flavonoids can block the build-up of beta-amyloid plaque in the brain, a hallmark of Alzheimer’s disease.
Flavonoids can also improve blood flow to the brain. Some studies have shown that flavonoid intake is inversely linked to cardiovascular disease, and what is good for the cardiovascular system is also good for the brain.
Large human studies on flavonoids are still in their infancy, but the first findings are promising. One of the most significant to date was a recent study linking a high intake of flavonoids to a lower risk of Alzheimer’s disease and related dementias (conditions with symptoms similar to Alzheimer’s disease). The results were published online April 22, 2020 by The American Journal of Clinical Nutrition.
Using data from the Framingham Heart Study, researchers looked at the eating habits of nearly 3,000 people, an average of 59 years old, without any signs of dementia. Over 20 years, people with the highest daily intake of flavonoids (about 297 milligrams) had a lower risk of developing Alzheimer’s disease or related dementia than those who consumed the smallest amounts (about 123 milligrams). ).
Still, the link between flavonoids and brain health could be a coincidence. It may take a team effort from all kinds of nutrients, but flavonoids can be one of the main players.
How many do you need? There is no defined recommended daily allowance for flavonoids. Three servings of vegetables and two servings of fruit per day is the commonly suggested goal. The more colors and types of food you can put on your plate at each meal, the better. This should be a great start to giving you the flavonoids that your body – and your brain – may need.
(Howard LeWine, MD, is an internist at Brigham and Women’s Hospital in Boston and an assistant professor at Harvard Medical School. For more information on consumer health, please visit www.health.harvard.edu.)