According to a new study, eating more flavonols, antioxidants found in many vegetables, fruits, tea and wine, can slow your rate of memory loss.
The cognitive score of the people in the study who ate the most flavonols declined 0.4 units per decade slower than those who ate the least flavonols. The results held even after adjusting for other factors that can affect memory, such as age, sex and smoking, the study recently published in Neurology, the medical journal of the American Academy of Neurology.
“It’s exciting that our study shows that making specific food choices can lead to slower cognitive decline,” said study author Dr. Thomas Holland, an instructor in the Department of Internal Medicine. at Rush University Medical Center in Chicago, in a statement.
“Something as simple as eating more fruits and vegetables and drinking more tea is an easy way for people to take an active role in maintaining their brain health. »
Flavonols are cytoprotective, meaning they protect cells, including neurons, so it’s plausible there could be a direct impact on cognition, said preventative medicine specialist Dr David Katz and lifestyle and nutrition who did not participate in the study.
“But they’re also a marker of higher consumption of fruits and vegetables — which is good for the brain because it’s good for every vital organ and for the body as a whole,” Katz said in an e -mail.
“They may also be a marker of better overall diet quality, or even greater health awareness. More health conscious people can do things to preserve their cognition, or perhaps being more health conscious is a byproduct of better cognition.
Plants contain over 5,000 flavonoid compounds, which play a role in producing cell growth, controlling environmental stress and attracting insects for pollination.
Flavonols, a type of flavonoid, have been shown in animal studies and some human studies to reduce inflammation, a major trigger of chronic disease, and are rich sources of antioxidants. Antioxidants fight free radicals, “highly unstable molecules that form naturally when you exercise and when your body converts food into energy,” according to the National Center for Complementary and Integrative Health, part of the National Institutes of Health.
One of the most common flavonols, quercetin, has shown promise in reducing the occurrence of colorectal infections. cancer and other cancers, according to studies. Onions contain the highest levels – lower levels can be found in broccoli, blueberries, cauliflower, kale, leeks, spinach and strawberries.
Another common flavonol, kaempferol, appears to inhibit cancer cell growth while preserving and protecting normal cells. Good sources of kaempferol are onions, asparagus, and berries, but the richest vegetable sources are spinach, kale, and other green leafy vegetables, as well as herbs such as chives, dill, and tarragon.
A third major player is myricetin, which has been studied in rodents for controlling blood sugar and reducing tau, a protein that causes the characteristic tangles of Alzheimer’s and other dementias. Spinach and strawberries contain high levels of myricetin, but honey, black currants, grapes and other fruits, berries, vegetables, nuts and tea are also good sources.
The last group of flavonols, isorhamnetin, may protect against cardiovascular and neurovascular diseases in addition to anti-tumor and anti-inflammatory benefits. Good sources of isorhamnetin are pears, olive oil, wine and tomato sauce.
You can find a complete list of the flavonoid content of various fruits and vegetables here.
The new study asked 961 people with an average age of 81 and no signs of dementia to complete a food questionnaire every year for seven years. Additionally, participants underwent annual cognitive and memory tests and were asked about their time spent being physically and mentally active.
People were divided into groups based on their daily flavonol intake. The lowest intake was around 5 milligrams per day; the highest 15 milligrams per day — equivalent to about a cup of dark leafy greens, according to the study. (For comparison, the average flavonol intake among American adults is about 16 to 20 milligrams per day, depending on the study.)
The study looked at the impact of the four main flavonols – kaempferol, quercetin, myricetin and isorhamnetin – on the rate of cognitive decline over the seven years.
The greatest impact was found with kaempferol: people who ate the highest amounts of kaempferol-containing foods showed a slower rate of cognitive decline of 0.4 units per decade compared to those who ate the least , according to the study.
Myricetin was as follows: People who ate the most myricetin-containing foods had a slower rate of cognitive decline by 0.3 units per decade compared to the lowest-consuming group. People who ate the most quercetin-containing foods had a slower rate of cognitive decline of 0.2 units per decade.
Dietary isorhamnetin had no impact, according to the study.
Despite the apparent positives, studies on the impact of flavonols on human health have been inconclusive – mainly because many are observational and cannot show direct cause and effect. This also applies to the neurology study, according to its authors.
A few randomized controlled trials – the scientific gold standard – have shown benefits associated with flavonols for controlling blood sugar in type 2 diabetes and improve cardiovascular health, according to the Linus Pauling Institute, home to the Micronutrient Information Center, an online database of nutritional information.
It’s unclear whether these benefits are long-term, the institute said, and no clear impact has been shown for cancer prevention or cognitive protection.
“There are other bioactives that may contribute to the observed results,” Katz said. “Further studies are needed to fully isolate the effects of flavonoids. »
There’s also a downside to assuming a health impact without the necessary studies to prove it, said Dr. Christopher Gardner, research professor of medicine and director of the Nutrition Studies Research Group at Stanford University.
“You can count on Americans who want the goodness of plants but don’t want to eat them,” he said in an email.
“(And) if people read the headline and rushed out and bought bottled flavonols (extracts) instead of eating whole plant foods, and it turns out it wasn’t just the flavonols, it was the package of everything in these plants (instead).”