A twelve-week study indicates that middle-aged individuals with overweight and signs of insulin resistance who consumed the equivalent of one cup of strawberries daily experienced better memory and fewer depressive symptoms compared to the control group.

With dementia on the rise, along with metabolic disorders such as insulin resistance, obesity, and related health issues, the study aimed to explore whether strawberry consumption could enhance cognitive performance and metabolic health in this population. Neurologist Robert Krikorian from the University of Cincinnati explains, "In this study, we assessed whether strawberry consumption could improve cognitive performance and metabolic health in this population, and if so, whether there might be a relationship between improved cognitive function and reduced metabolic disturbances."

Krikorian and his team in the United States recruited 30 adults, primarily women aged 50 to 65, with mild cognitive impairments and a body mass index (BMI) classifying them as overweight.

Participants were asked to avoid consuming any berry fruits for two weeks prior to the study, while during the study, they were given a thirteen-gram strawberry powder supplement or a placebo daily. The participants' executive function, word search, long-term memory, and mood were assessed using cognitive tests before and after the study, and researchers monitored metabolic data.

Those who received the placebo did not perform as well on the delayed recognition test, which measures something called memory interference. However, in individuals given the strawberry powder, memory interference was reduced, suggesting that these individuals were better able to ignore irrelevant information.

"Reducing memory interference means less semantic confusion in the test of learning from a word list," explains Krikorian. "In general, this phenomenon is believed to reflect better executive control in resisting intrusion of non-target words during memory testing."

Participants who received the strawberry powder also reported fewer depressive symptoms, indicating better emotional coping and executive abilities—meaning better ability to manage daily activities and social relationships, as well as improved reaction control and greater flexibility.

The researchers note that age and insulin resistance likely contributed to mild executive function impairments in many participants, suggesting that the "treatment" partially corrected existing deficiencies. However, they do not know whether strawberries would improve the functioning of individuals without impairments.

"Executive functions start to decline in middle age, and excess fat in the abdominal cavity, as seen in insulin resistance and obesity, tends to increase inflammation, including in the brain," adds Krikorian. "So the beneficial effects we observed may be related to a moderate anti-inflammatory effect of the strawberries."

A study conducted in 2022 by the same researchers and several collaborators showed that in a similar group of individuals, those who consumed berries daily had reduced levels of memory interference.

"Both strawberries and berries contain antioxidants called anthocyanins, which have been associated with a range of health benefits, such as improving metabolism and cognitive function," says Krikorian.

Other studies on strawberries in the diet have shown improvements in metabolism, including lower insulin levels, but this study did not demonstrate any metabolic effects.

"The unexpected lack of metabolic benefits may reflect a lower dose of anthocyanins used in this study compared to other studies assessing metabolic and cognitive functions," the team writes.

Krikorian and the team cannot draw general conclusions from their findings due to the small sample size, short duration of the study, and limited dietary regulations for participants. Studying the impact of food that is never consumed in isolation on health is challenging because our bodies have complex nutritional requirements.

Despite potential cognitive benefits, experts generally recommend a varied and balanced diet, which may include strawberries as an excellent source of vitamin C, as the best approach to obtaining necessary vitamins, minerals, and nutrients.

"These considerations emphasize the need for further research into the health and neurocognitive benefits associated with strawberry supplementation using different doses, larger samples, and intervention periods of varying lengths," the authors conclude.