Can flavonoids help fight forgetfulness?



The staple of a healthy diet is a vibrant rainbow of fruits and vegetables, like pinkish red strawberries, dark green spinach leaves, or sunny yellow peppers. Their colors often come from flavonoids, powerful plant chemicals (phytochemicals) that appear to contribute to many aspects of health. And now, a large Harvard study published online in Neurology in July suggests that flavonoids may also play a role in protecting cognition.


Scientists evaluated health data and self-reported diet information from more than 77,000 middle-aged men and women, collected over 20 years.

The information included how often participants ate many types of flavonoid-rich foods and whether participants reported cognitive changes in their 70s, such as difficulty

  • remember recent events or a short list of items
  • remember things from one second to the next
  • understand the instructions
  • following a group conversation or a television intrigue
  • find their way through the familiar streets.

The researchers then calculated participants’ intake of six classes of flavonoids:

  • flavonols (such as quercetin in onions and kale)
  • flavones (like luteolin in green peppers and celery)
  • flavanones (like naringenin in grapefruit and oranges)
  • flavan-3-ol monomers (such as the catechins in red wine and strawberries)
  • anthocyanins (such as cyanidin in blackberries and red cabbage)
  • polymers (such as theaflavins in black tea).

What the study found

After taking into account factors that might have affected cognition (such as age, weight, physical activity, alcohol consumption, depression, and intake of non-flavonoid nutrients), the scientists found that people with the highest daily intakes of flavonoids were 19% less likely to report problems. with memory and reflection, compared to people with the lowest daily intakes of flavonoids.

“Our results are exciting because they show that eating foods rich in flavonoids could help prevent or slow the decline of memory and other cognitive processes at the end of life,” says Dr. Walter Willett, one of the authors. of the study and professor of epidemiology and nutrition. at Harvard TH Chan School of Public Health.

“We noticed that early consumption of foods rich in flavonoids seemed to improve the protective effect on the brain. But even participants who started eating more flavonoids later in life saw benefits,” says Dr. Tian-Shin Yeh, lead author of the study and a postdoctoral researcher at the Harvard-Oxford Program in Epidemiology and the Department of Nutrition at the Harvard TH Chan School of Public Health.

The study was only observational, relying on what people remembered about their diet and what they noticed about cognition, and did not conclusively prove that consuming flavonoids maintained healthy eating habits. alert people in old age. But smaller or shorter-term studies have also found a link between flavonoids and cognitive health benefits.

Flavonoid Superstars

Some flavonoids in particular seemed to have protective effects on the brain:

  • Flavones were associated with a 38% lower risk of self-reported cognitive decline.
  • Flavanones had a 36% lower risk of self-reported cognitive decline
  • Anthocyanins had a 24% lower risk of self-reported cognitive decline.

Click here (note: automatic download) for a USDA list of the best choices for these three types of flavonoids.

The fruits and vegetables in the study most associated with beneficial cognitive effects, ranked from strongest to weakest, were:

  • Brussels sprouts
  • strawberries
  • cauliflower
  • raw spinach
  • yams / sweet potatoes
  • blueberries
  • yellow / orange winter squash
  • cooked spinach
  • cooked carrots
  • peaches / apricots / plums
  • cantaloupe
  • tomato juice
  • Applesauce
  • green / red / yellow peppers
  • broccoli
  • cabbage
  • tomato sauce
  • Romaine lettuce
  • tomatoes
  • grapefruit
  • celery
  • beets
  • iceberg lettuce
  • baked / boiled / mashed potatoes
  • Orange juice
  • raw carrots
  • apples / pears
  • grapefruit juice
  • bananas
  • oranges
  • onions
  • apple juice / cider
  • tea
  • White wine
  • raisins / raisins
  • Red wine.

What is the magic of flavonoids?

We are not sure why flavonoids might play a role in protecting cognition. But we do know that flavonoids are powerful antioxidants, which can fight brain inflammation and amyloid buildup, a hallmark of Alzheimer’s disease.

Antioxidants may also play a role in

  • keep blood vessels healthy (which keeps blood flowing to the brain)
  • increase the production of brain-derived neurotrophic factors, chemicals that repair brain cells, strengthen their connections, promote the growth of new brain cells, and increase the size of your hippocampus (a part of the brain involved in storing and retrieving blood memories).

Additionally, we know that flavonoids are associated with fighting inflammation and tumor growth, and lowering blood pressure.

Set simple flavonoid goals

With so many potential benefits for flavonoids, you might be wondering what kind of levels you should be aiming for in your diet. In the study, flavonoid intakes ranged from low – about 150 milligrams (mg) per day – to high – about 620 mg per day.

But tracking flavonoids is complicated. They vary a lot depending on the food. For example, half a cup of blueberries contains about 165 mg of anthocyanins; half a cup of peppers contains about 5 mg of flavones. And many fruits and vegetables contain several types of flavonoids, as well as many other phytochemicals.

So don’t stress about it. Just eat a diet with a wide variety of fruits and vegetables – the sooner you start, the better. Try to reach the goal of five fruits and vegetables per day (recent evidence suggests that the most effective combination is two servings of fruit plus three servings of vegetables per day).

Then when you enjoy foods like strawberries, blueberries, peppers, celery, apples, bananas, oranges, and grapefruits, remember that they are not only tasty and good for your overall health. , but they are also potentially useful for your brain.

“It’s called ‘eating the rainbow’ and can lead to healthier and more delicious food; and that’s another reason we should make sure everyone has access to fruits and vegetables. fresh vegetables, ”says Dr. Deborah Blacker, a co-study. author and professor and vice-president of epidemiology at Harvard TH Chan School of Public Health.

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