The Summer Fruit A Nutritionist Wants You To Eat For Cognition & Heart Health

Researchers at San Diego State University conducted a randomized control trial comparing the effects of 26 grams of freeze-dried strawberry powder to a control powder. Participants, a mix of men and women in their 70s, ate one of the two powders daily for eight weeks. After a four-week washout period (during which participants returned to their usual diets sans powders), they returned to the lab for a series of tests.

Researchers looked specifically at the effects on cognition, which they measured via a series of tests developed by the National Institute of Health. (The tests involve things like recalling words from a list and grouping items of different colors.) Researchers were also interested in the strawberries' effect on cardiometabolic health, which they measured by noting changes in blood pressure, biomarkers, and waist circumference.

After the eight-week trial and four-week wash-out period, the strawberry powder group showed increased processing speed and episodic memory—a kind of long-term memory that allows us to recall previous experiences and the contexts in which they took place. The strawberry group also experienced more positive changes in systolic blood pressure (aka blood pressure measured during a heartbeat2) than the control group.

There are two things to consider when applying these results. First, the study was funded by the California Strawberry Commission. While research funded by trade groups should be approached with some skepticism, it's not necessarily unreliable. And the findings of this study are in line with existing research on the benefits of strawberries. 3

Secondly, it's worth noting that participants ate freeze-dried strawberry powder rather than whole strawberries. This was likely so that the study could be reasonably double-blind. (If half the participants were given whole strawberries and the other half were given a powder, it would be pretty clear to the placebo group that they were given a placebo.) But while freeze-dried berries are more concentrated than whole fruits, they have a similar nutritional composition, according to USDA data4.

The powder participants ate was equivalent to about 16 large or 24 medium strawberries, about two servings1, says Maggie Moon, RD, a brain health nutrition expert and author of The MIND Diet. Moon adds that the findings could be extrapolated to eating whole strawberries because "it’s likely that it’s the polyphenols in strawberries that promote memory and cognition brain health benefits, and the levels aren’t that different in fresh versus freeze-dried berries."

In support of the findings, Moon adds that the vitamin C content in whole berries can support immunity and help the body absorb iron from plant sources. The fiber found in berries promotes satiety and fights cholesterol, while the folate in strawberries supports neurotransmitter production.

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