Study suggests foods with this compound could help boost memory

Heading to the grocery store? Don't forget to get some flavanols while you're there. 

If you happen to forget, researchers published a recent study on May 30, which found that eating foods containing flavanols – naturally occurring compounds found in plants – resulted in improved memory function.

"These are exciting results because they suggest that there is an optimum amount of flavanols in the diet," Gunter Kuhnle, study co-author and professor of Nutrition and Food Science at the University of Reading in the UK, said in a news release.

According to the study, Red wine, black and green tea, dark chocolate, beans, kale, watercress, onions and fruits like cherries, blackberries, black grapes and apples contain healthy levels of flavanols. 

In the study, nearly 4,000 participants took 500 mg of a flavanol supplement in the form of a pill, or a placebo for three years. Researchers then tested memory every year using tests for short-term memory. 

For people who already had high levels of flavanols in their diets before the study, not much memory improvement was noted. 

However, those who had barely any flavanol in their diets scored high on the researcher's memory tests with a boost of 16% in test score. 

In a separate study of 18 men published in 2020, researchers at the University of Birmingham found that drinking cocoa improved participants’ ability to quickly solve a series of complex mental tests.

The team chalked up the heightened sharpness  — including that subjects finished tests up to 11% faster — to the brain-boosting compound flavanol, which is found naturally in chocolate, according to the study, published Tuesday in the journal Scientific Reports.

"We used cocoa in our experiment, but flavanols are extremely common in a wide range of fruit and vegetables," said the report’s lead author, Catarina Rendeiro. "It also further suggests that flavanols might be particularly beneficial during cognitively demanding tasks."

During the study, the researchers tracked how participants, who were all healthy and ages 18 to 40, reacted to brain-teasing tests before and after sipping the sweet brew.

The team found that after drinking hot chocolate, participants’ blood oxygenation levels increased up to threefold and that their test times and accuracy rates improved.

They also discovered that every participant’s performance improved when researchers added extra flavanol into normal hot chocolate, according to the study, which notes brain power is linked to oxygen levels.

"We can link this with our results on improved blood oxygenation — if you’re being challenged more, your brain needs improved blood oxygen levels to manage that challenge," Rendeiro said.

"By better understanding the cognitive benefits of eating these food groups… we can offer improved guidance to people about how to make the most of their dietary choices."

FOX News contributed to this story.