We’ve all heard that eating chocolate temporarily improves our brain function. There are even studies done about it, determining that moderate and short-term intake of chocolate improves the brain blood flow and oxygen levels thanks to flavanols – plant-based substances in cocoa that have antioxidant and anti-inflammatory effects.
Of course, the problem with chocolate is that it brings as many negatives as it does positives. Enter blueberries.
A recent placebo-controlled and double-blind study determined that eating a cup of blueberries can also have a drastic positive effect on the cognitive performance of healthy adults in the age range between 40 and 65 years. The study was conducted by doctors Adrian R. Whyte, Sajida Rahman, and others, and it was published in the European Journal of Nutrition.
The study is called “Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry” and its findings support previous research in the 24-30 year age groups which reached similar conclusions. Other studies also share these findings for healthy children, teenagers, and young adults.
The purpose of the study was to find out if these effects can be observed in healthy older adults as well.
The goal of the study isn’t to find treatments of cognitive ailments but to determine how healthy adults can improve their cognitive potential in an easy manner. To do that, the study used a small dose of blueberries. As per the study’s description, they used:
“The wild blueberry beverage consisted of 25 g freeze-dried whole wild blueberry (WBB) powder (~1-cup fresh weight) […] The WBB powder was mixed with water, frozen lemonade concentrate, and unsweetened Kool-aid for color and flavoring. The placebo beverage was matched as closely as possible for energy and macronutrient content using the same ingredients minus the WBB powder.”
How well was the study conducted?
The study worked with 35 participants between 40 and 65 years (average of 50.9). 23 were female and 12 were male, all of them were in good health and didn’t have any diagnosable cognitive impairments.
Despite the relatively small sample size, the study was very well conducted. It was randomized, placebo-controlled, and double-blind. This means that the participants were given two doses of powder over a period of time – one was the study’s freeze-dried wild blueberry WBB powder and one was a simple placebo.
Additionally, the administration of the blueberry powder and the placebo were randomized. Neither the participants nor the researchers knew when and who was given the placebo and when – the blueberry powder. This ensured that there wouldn’t be any bias from either side.
Before and after the ingestion of both the placebo and the blueberry powder, the participants went through a series of psychological tests. The tests aimed to assess both the executive abilities and the memory of the participants. There was also an Auditory Verbal Learning Task which measured the learning, recall, and recognition abilities of the participants.
A cued Go/No-Go task assessed the participants’ reaction times and response inhibition while a Modified Attention Network Task examined their susceptibility to response interference, i.e. how easily distracted they were after eating the blueberry powder and after eating the placebo.
The wild blueberry powder was determined to have positive cognitive effects in all participants and in almost all cognitive tests. There were also no observed negative side-effects which could be viewed as a possible mistake in the study but that’s unlikely given the very small amount of blueberries (25 g) ingested.
As the researchers summarize the results:
“WBB cognitive performance was improved in comparison to placebo on delayed recognition memory and aspects of executive function. Importantly, these benefits were found on more demanding elements of the tasks where some form of additional cognitive effort was required.”
They also observed improvements in the and the sustained attention capabilities of all participants. The results are very promising as blueberries present a nearly drawback-free way of improving one’s cognitive abilities in/before cognitively demanding situations, regardless of age.
“… different cognitive domains appear affected following acute flavonoid/polyphenol interventions dependent on the age of the participants tested with memory improvements generally being observed in children and older adults, executive function improvements in children, younger, and middle-aged adults, and working memory improvements more typically observed in younger and middle-aged adults …”
The researchers concluded that “The findings provide further support for the efficacy of wild blueberry on improving cognitive outcomes within this age group, particularly where there is increased cognitive demand.”
Should we just consume blueberries freely for cognitive improvement?
Blueberries are a well-known type of fruit that has no recorded negative side-effects when taken in acceptable doses. As with any other fruit or food, overeating with them may lead to some blood sugar and digestion issues but there’s no need to overeat with blueberries if your goal is cognitive enhancement as doses of ~25-30 grams are more than sufficient for that.
Furthermore, when taken in adequate amounts, blueberries also have a lot of other well-documented benefits:
- Blueberries are high in nutrients but low on calories. They are exceptionally rich in vitamins C and K, as well as on Manganese and fiber.
- Lots of antioxidants. One of the many reasons why blueberries are effective for improving our cognitive performance seems to be that they’re rich in antioxidants. This has many other benefits for our overall health in addition to cognitive enhancement.
- Heart disease prevention is another thing blueberries seem very helpful with. A study of 93,600 nurses has determined that those with regular intake of anthocyanins (the main antioxidant in blueberries) had a 32% lower risk of heart attacks.
- The antioxidants in blueberries are also believed to help prevent diabetes. Multiple studies show that blueberries have a beneficial effect on insulin sensitivity which can be very beneficial.
- A small serving of 50 g blueberries per day also lowers LDL “bad” cholesterol by 27% in obese people.
- The same study also shows that a small daily dose of blueberries can help lower blood pressure in both obese people and postmenopausal women.
- Blueberries reduce oxidative DNA damage which helps prevent both aging and cancer.
So, while blueberries are certainly no panacea, a regular moderate intake of this small, bush-growing super-fruit offers a lot of benefits!