What to Know About the Connection Between Blueberries and Memory
Two new reviews suggest blueberries are great for cognition. Does that mean they’re this year’s superfruit?
Blueberries are fascinating to scientists. In humans, the berries have been shown to lower blood pressure and help kids perform better on cognitive tests. In rats, there’s evidence the fruit improves working memory and helps the animals balance. It seems the simple berry has a lot to offer the brain.
Two recently published systematic reviews — summaries of already conducted research — support that theory. Both studies found that the overall scientific literature suggests that eating blueberries can improve overall cognitive performance and help elevate mood.
Wolfgang Marx, a nutrition researcher at Deakin University in Geelong, Australia, who co-authored one of the reviews published in the journal Brain, Behavior, and Immunity, says blueberries are receiving a lot of research attention because they are a rich source of micronutrients, and epidemiological studies from the last decade have found that eating flavonoid-rich foods can improve cognitive decline.
As part of the review, Marx and colleagues identified 12 studies — all randomized control trials, considered the gold standard in research — that looked at the effect of eating blueberries on short-term, long-term, and spatial memory. They found that a number of trials showed significant improvements in various measures of cognitive ability after men and women in the studies ate blueberries. The other review, published in June by another research group, looked at 11 studies exploring the link between blueberries and cognitive performance and found that people who eat berries performed better on memory tasks.
So, can blueberries be named fruit of the year?
Not so fast.
While this new research certainly supports the well-known fact that berries are a healthy food, that doesn’t necessarily mean everyone who wants a memory boost should start chowing down on a carton of them. All of the studies reviewed by Marx and his team are quite small and the experiments were carried out over short periods of time. What’s more, each study used a variety of different tests to measure cognition as well as different protocol, making it difficult to compare the results of one study to another.
For instance, some studies used freeze-dried blueberries, while others used whole blueberries or blueberry concentrate. The studies also tested different age groups. While the majority focused on children, others were conducted on young adults or older people with or without cognitive impairment.
In a letter to the editor submitted to Brain, Behavior, and Immunity about the berry studies, researchers Christopher Brydges and Laura Gaeta of Colorado State University argued that whether blueberries are beneficial for the brain and mood still remains an open question. “Based on the current research… researchers should avoid drawing any definitive conclusions regarding the effects of blueberries on cognitive performance or mood,” they write.
Even if it’s true that berries offer benefits to the brain, it’s unclear how great of an effect that is. “The proportion of studies that report effects are only just statistically significant,” Brydges and Gaeta told Elemental.
Marx largely agrees with the criticism, and says blueberry research is in its early days, so medical recommendations that people eat them with the purpose to improve memory is premature. “It’s an interesting area,” he says. “But we need some proper long-term larger studies to actually say whether this is a true effect.”
If blueberries do turn out to benefit the brain, it’s likely due to their antioxidant and anti-inflammatory properties. Tamping down on inflammation could benefit brain cell health, and antioxidants may help keep other health conditions (like high blood pressure) at bay, which can also allow for better brain health.
While the link between blueberries and improved memory remains uncertain, Marx still recommends that people eat them — they are a healthy fruit, after all. So far, most research suggests two cups of blueberries a day may be an ideal dose. But he also points out that other sources of polyphenols have similar benefits. Orange juice, for instance, has been shown to help lower blood pressure by widening blood vessels. Black tea, green tea, and extra-virgin olive oil are also rich in polyphenols. “Even if you perhaps don’t like blueberries,” he says, “trying to consume these polyphenol-rich foods in general can’t be a bad thing.”