Why Fruits and Vegetables May Lower Alzheimer’s Risk

Flavonols, found in fruits and vegetables, were tied to a lower risk of Alzheimer’s disease.

By Nicholas Bakalar
Feb. 4, 2020, 5:00 a.m. ET






Flavonols, a large class of compounds found in most fruits and vegetables, may be associated with a reduced risk for Alzheimer’s disease. Flavonols are known to have antioxidant and anti-inflammatory effects, and animal studies have suggested they may improve memory and learning.

A study in Neurology involved 921 men and women, average age 81 and free of dementia, who reported their diet using well-validated food questionnaires. During an average follow-up of six years, 220 developed Alzheimer’s disease.

People with the highest levels of flavonol intake tended to have higher levels of education and were more physically active. But after controlling for these factors plus age, sex, the Apo E4 gene (which increases the risk for dementia) and late-life cognitive activity, the scientists found that compared with those in the lowest one-fifth for flavonol intake, those in the highest one-fifth had a 48 percent reduced risk for Alzheimer’s disease.

The study covered four types of flavonols: kaempferol, quercetin, isorhamnetin and myricetin. All except quercetin showed a strong association with Alzheimer’s risk reduction.

These flavonols are available as supplements, but the lead author, Dr. Thomas M. Holland, a professor of medicine at Rush Medical College in Chicago, said that foods are a better source. “You get a broader intake of vitamins, minerals and bioactives in food than in the supplements,” he said.

Flavonoider är en grupp kemiska föreningar som bland annat är verksamma som antioxidanter.Flavoner är gula färgämnen och förekommer rikligt i våra växter samt i äggulan. Flavon ingår till stor del i riboflavin eller B2-vitamin. Äter man mycket färgrikt och gult får man i sig ordentligt med vitaminer. B-vitaminer är vattenlösliga och överskottet följer med urinen ut, så det är ingen risk att man får för mycket. Många flavonoider är mycket instabila, de bryts ned vid produktion av livsmedel, pastörisering och förvaring.

Från sin upptäckt i mitten av 1930-talet av ungraren Albert Szent-Györgyi (nobelpristagare 1937) och fram till början av 1950-talet kallades flavonoider för P-vitamin.