Improve memory as you age by eating more flavonols, study says

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Eating more flavonols, antioxidants found in many vegetables, fruits, tea and wine, can reduce the rate of memory loss, a new study has found.

The cognitive scores of people in the study who ate the most flavonols declined 0.4 units per decade more slowly than those who ate the least flavonols. The results were held even after adjusting for other factors that can affect memory, such as age, sex and smoking, according to a study recently published in Neurology, a medical journal of the American Academy of Neurology.

“It’s exciting that our study shows that making certain dietary choices can lead to slower cognitive decline,” said study author Dr. Thomas Holland, instructor in the department of internal medicine. at Rush University Medical Center in Chicago, in a statement.

“Something as simple as eating more fruit and vegetables and drinking more tea is an easy way for people to take an active role in maintaining brain health.”

Flavonols are cytoprotective, meaning they protect cells, including neurons, so they may have a direct effect on cognition, said Dr. David Katz, a preventive medicine and lifestyle and nutrition specialist who was not involved in the study.

Onions contain the highest levels of quercetin, one of the most common flavonols.

“But it’s also a marker of higher fruit and vegetable intake — which is good for the brain because it’s good for every vital organ, and the organism as a whole,” Katz said in an email.

“They can also be a sign of better overall diet quality, or greater health awareness. People who are more health conscious may do things to maintain their cognition, or they may become more health conscious as a byproduct of better cognition.

Plants contain more than 5,000 flavonoid compounds, which play a role in producing cell growth, combating environmental stress and attracting insects for pollination.

Flavonols, a type of flavonoid, have been shown in animal and several human studies to reduce inflammation, a major trigger of chronic disease, and are a rich source 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 colorectal attacks. cancer and other cancers, according to studies. Onions contain the highest levels – lower levels can be found in broccoli, blueberries, cauliflower, curly kale, onions, spinach and strawberries.

Another common flavonol, kaempferol, appears to inhibit the growth of cancer cells while preserving and protecting normal cells. Good sources of kaempferol are onions, asparagus and berries, but the richest plant sources are spinach, kale and other green vegetables, as well as herbs such as chives, dill and tarragon.

A third major player is myricetin, which has been studied in mice to control blood sugar and reduce tau, the protein that causes the tangles characteristic 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, can protect against cardiovascular and neurovascular diseases in addition to its 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 fill out a food questionnaire every year for seven years. In addition, participants underwent annual cognitive and memory tests and were asked about the amount of time they spent being physically and mentally active.

People were divided into groups based on their daily intake of flavonols. The lowest intake is about 5 milligrams per day; the highest 15 milligrams a day – equal to about a cup of dark green leaves, study noted. (For comparison, the average flavonol intake in US adults is about 16 to 20 milligrams per day, according to the study.)

The study looked at the effect of four main flavonols – kaempferol, quercetin, myricetin and isorhamnetin – on the rate of cognitive decline over seven years.

The biggest impact was found with kaempferol: People who ate the most foods with kaempferol showed a cognitive decline of 0.4 units per decade slower compared to people who ate the least, according to the study.

Myricetin next: People who ate the most foods with myricetin had a 0.3 unit per decade slower rate of cognitive decline compared to the group with the least. People who ate the most foods with quercetin showed a cognitive decline of 0.2 units per decade.

Dietary isorhamnetin had no effect, the study found.

Despite the apparent positives, studies on the impact of flavonols on human health are still inconclusive – mainly because most of them are observational and cannot show direct cause and effect. That applies to the study of Neurology as well, according to the author.

Several randomized controlled trials – the scientific gold standard – have shown benefits associated with flavonols in 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 is not known whether the benefits are long-term, the agency said, and there is no clear effect on cancer prevention or cognitive protection.

“There are other bioactives that may contribute to the observed results,” Katz said. “Additional studies are needed to fully isolate the effects of flavonoids.”

There is also a lack of consideration of health impacts without the necessary research to support them, said Dr. Christopher Gardner, professor of drug research and director of the Nutrition Research Group at Stanford University.

“You can count on Americans who want the benefits of plants but don’t want to eat them,” he said in an email.

“(What) if people read the title and rush out and buy flavonol in a bottle (extract) instead of eating plant food, and it turns out not only flavonol, but everything in the plant (but) .”

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