Eating foods high in flavonoids have now been shown in the research to reduce cognitive decline. Other research shows that flavonoids boost immunity. They also reduce something called neuroinflammation.
Let’s take a quick look at the research before we discuss which foods are highest in flavonoids.
Flavonoids reduce cognitive decline
Scientists from the American Academy of Neurology examined history and diets for over 78,000 people in their late forties and early fifties.
They examined data from 49,493 women, average age of 48. And 27,842 men with an average age of 51. Over a 20 year period, the subjects answered a number of questionnaires on their diet.
From this data, the researchers extrapolated the flavonoid intake in their diets. They also determined the frequency of flavonoid consumption.
The subjects also underwent cognition self-evaluations during the study. They answered questions such as:
“Do you have more trouble than usual remembering recent events?”
“Do you have more trouble than usual remembering a short list of items?”
The researchers found those who ate the highest amount of flavonoids had 20 percent less cognitive decline compared to those who ate the least amount.
How much flavonoids did they eat?
The greatest amount consumed was about 600 milligrams each day. Those who consumed the least amount of flavonoids ate about 150 milligrams.
150 milligrams translates to very little fresh fruits and vegetables. About the amount contained in one apple.
What are flavonoids?
Flavonoids are produced by plants as a result of converting nutrients and ultraviolet radiation. Nitrogen fixation is often involved.
Plants produce flavonoids to help protect them from diseases and invaders. These include bacteria and fungi, along with insects.
Flavonoids are often evidenced in foods by their colors. But this is not in every case. Flavonoids include isoflavones, flavonols, flavanones, flavanonols, anthocyanidins and anthoxanthins.
What foods are highest in flavonoids?
Foods known for their high flavonoid content include:
- Citrus fruits
- Dark chocolate (cocoa greater than 70%)
- Ginkgo biloba
- Green tea
The researchers in the study above found that flavones had the greatest positive effect on cognition. Flavones are found in parsley, celery, red peppers and orange fruits and vegetables. These flavones reduced cognitive decline risk by 38 percent.
The research also found that anthocyanins reduced decline significantly as well. Anthocyanins consumption found in blue and purple berries like blueberries, blackberries and cherries, resulted in 24 percent reduced cognitive decline.
The study was published in Neurology, the journal of the American Academy of Neurology.
“There is mounting evidence suggesting flavonoids are powerhouses when it comes to preventing your thinking skills from declining as you get older,” said lead study author Walter Willett, MD, DrPH, of Harvard University.
“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. “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. And 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.”
Flavonoids reduce neuroinflammation
Research has also found that flavonoid foods also reduce inflammation in the brain and nervous system – called neuroinflammation.
A 2020 study from Turkey’s Selcuk University medical school studied the body’s inflammatory response. They found that flavonoids reduced brain injury from inflammation and promoted a process of neurogenerative healing.
Catechins and quercetin were both found to be involved in this process.
Flavonoids help fight gum disease
Another study from Harvard found that flavonoid consumption reduced periodontitis incidence. This is also connected to brain inflammation and loss of cognition.
The researchers followed nearly 35,000 men since 1986. They found that those who consumed higher amounts of flavonoids had a significant reduction in periodontitis.
Other research has found that flavonoids also help reduce stomach cancer risk.
Tian-Shin Yeh, Changzheng Yuan, Alberto Ascherio, Bernard Rosner, Walter Willett, Deborah Blacker. Long-term Dietary Flavonoid Intake and Subjective Cognitive Decline in US Men and Women. Neurology Jul 2021, 10.1212/WNL.0000000000012454; DOI: 10.1212/WNL.0000000000012454
STUDY: ADDING COLOR TO YOUR PLATE MAY LOWER RISK OF COGNITIVE DECLINE. Diet High in Flavonoids Linked to 20% Reduction in Risk
Calis Z, Mogulkoc R, Baltaci AK. The Roles of Flavonols/Flavonoids in Neurodegeneration and Neuroinflammation. Mini Rev Med Chem. 2020;20(15):1475-1488. doi: 10.2174/1389557519666190617150051.
Serafini M, Peluso I, Raguzzini A. Flavonoids as anti-inflammatory agents. Proc Nutr Soc. 2010 Aug;69(3):273-8. doi: 10.1017/S002966511000162X.
Alhassani AA, Hu FB, Rimm EB, Li Y, Rosner BA, Willett WC, Joshipura KJ. Dietary flavonoid intake and risk of periodontitis. J Periodontol. 2020 Jan 16:10.1002/JPER.19-0463. doi: 10.1002/JPER.19-0463.