Consuming or drinking more flavonol-rich foods, such as fruits, vegetables, tea, and wine, may prevent memory loss, suggests a study published online in the journal Neurology.
People who eat or drink more foods with antioxidant flavonols, which are found in many fruits and vegetables as well as tea and wine, may have a slower rate of memory decline, suggests a new analysis published in the online issue of Neurology, the medical journal of the American Academy of Neurology (Holland et al., 2022).
Thomas M. Holland, MD, MS, from the Rush University Medical Center in Chicago, who authored the study, remarked, “It’s intriguing to speculate that specific dietary choices may contribute to a slower pace of cognitive decline.”
“People can actively preserve brain health by consuming more fruits and vegetables and drinking more tea.”
Flavonoids are a family of polyphenolic secondary metabolites found in plants that humans commonly consume. In the 1930s, Albert Szent-Gyorgyi and colleagues discovered that simple yellow extract from oranges, lemons, or paprika was more effective than Vitamin C alone at preventing scurvy. The enhanced activity of this extract was initially attributed to “Vitamin P,” later renamed flavonoids.
It has long been recognized that flavonoid-rich diets have several health benefits (Yao et al., 2004). Several studies indicate that flavonoids protect the cardiovascular system and prevent diabetes, obesity, and cancer (Kawser Hossain et al., 2016, Ballard et al., 2019).
The Neurology study examined if ingestion of flavonoid-rich foods enhances cognitive performance in older adults.
The Study
The study comprised nine hundred sixty-one 81-year-olds without dementia. They responded to an annual food frequency survey. Annual cognitive and memory tests included recalling and arranging words and numbers. In addition, they were asked about their education, physical exercise, and mental activities, such as reading and gaming. The average duration of follow-up was seven years.
The study subjects were divided into five equal groups based on the amount of flavonol consumed. The population studied consumed 10 mg of total flavonols per day, compared to the average consumption of 16 to 20 mg for adults in the United States. The lowest group consumed 5 mg daily, whereas the highest group consumed 15 mg, equivalent to one cup of dark leafy vegetables.
Researchers used a 19-test global cognition score to evaluate cognitive decline. The average score ranged from 0.5 for healthy individuals to 0.2 for those with mild cognitive impairment to -0.5 for those with Alzheimer’s disease.
After adjusting for age, sex, and smoking, researchers found that those with the highest flavonol intake saw 0.4 units per decade less cognitive decline than those with the lowest intake. Holland believed the antioxidant and anti-inflammatory properties of flavonols were responsible.
The investigation categorized flavonols as kaempferol, quercetin, myricetin, and isorhamnetin. In each category, the foods that contributed the most quercetin, myricetin, and isorhamnetin were kale, beans, tea, spinach, broccoli, quercetin, and myricetin.
Cognitive decline was 0.4 units per decade slower among those with the highest kaempferol consumption than those with the lowest. Cognitive decline was 0.2 units per decade slower in those with the highest quercetin intake than those with the lowest. Those who consumed the most myricetin had 0.3 units per decade slower cognitive deterioration than those who consumed the least. Diet had no effect on global cognition.
Significance
Holland emphasized that the evidence merely implies flavonols slow cognitive decline.
Although the food frequency questionnaire proved valid, it was self-reported, so individuals may need to recall what they eat.
The National Institutes of Health, Aging, and Agriculture Research Service financed the study.
