One Dose of Blueberries Boosts Cognition within Hours
We knew blueberries were good for the brain. Now we know that even a single dose of blueberries can significantly boost a number of key cognitive functions, within hours.
Blueberries have been shown to increase cognition in a number of other studies. They also boost memory according to the research. These include long-term consumption and consumption over a couple of months.
Now we find that even a single dose will boost brain function within hours.
This sounds a bit fantastic, but the results are clear.
Blueberry and brain function tested
Researchers from the School of Psychology and Clinical Language Sciences at the UK’s University of Reading (Whyte et al. 2020) tested 35 adults between 40 and 65 years old. A total of 65 adults were screened initially. Those who had a medical condition, were smokers, were on medications or obese were removed from participation.
The study was a double-blinded crossover design and placebo-controlled. That means that each individual was tested twice – at least seven days apart – once with the placebo and once with the blueberry.
In each test, the blueberry group was given a drink containing 25 grams of freeze-dried wild blueberry powder. The placebo group also received a beverage with a similar flavor. The drink was consumed with a matching breakfast meal.
They were also studied for recent dietary history, and exercise activity.
During each test, the subjects were given cognitive function tests before the drink, and every two hours thereafter through eight hours.
The cognitive tests included tests for working memory and new learning retention, word recall, recognition memory, attention, response inhibition and reaction times.
They were also given blood tests nearly hourly to correlate any brain function and metabolic functioning.
Cognition boosted within hours
The testing found that that within hours, the blueberry groups (on each test) performed consistently better than the placebo groups. These improvements included word response accuracy and congruency, reaction time and reaction accuracy (Go/No Go cues).
In some cases, the cognitive function dropped through the day among the placebo group while the blueberry group experienced less of a decline. In other cases, cognitive function improved in the blueberry group while decreasing in the placebo group at certain intervals.
In general, most cognitive functions declined after breakfast in both groups. This has been seen in other studies that have tested glucose and insulin levels after eating (postprandial).
In should also be noted that the meals given to the participants were somewhat typical UK high-fat content breakfast meals. These are known to reduce cognition after breakfast.
Nevertheless, the blueberries boosted cognition further under demand according to the researchers:
“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. “
Metabolic function also improved
Through their blood tests, the researchers also found the metabolic function of the blueberry groups were improved over the placebo group.
Specifically, within the first two hours after breakfast, the blueberry group had lower glucose and insulin concentrations in their blood.
This didn’t necessarily relate directly to the cognitive performance. But we do know that the brain does function better on a more steady rise and fall of glucose and insulin levels.
This effect of blueberries on our glucose and insulin post-meal response has been studied previously. In a 2017 study (Bell et al.) 17 young adults were tested with and without blueberry (also freeze-dried powder).
They were tested periodically over a two-and-half-hour period after their meal that included the blueberry drink. The blueberries had a significantly better glucose and insulin response:
“Blueberries were observed to significantly extend the postprandial glucose response beyond the period observed for a sugar-matched control, characteristic of a beneficial glycaemic response. “
The brain needs lots of glucose, but a shock-and-awe approach is typically too much.
The essential components of blueberries are typically retained even when used in cooking or in jams. Studies indicate that it is the procyanidins and proanthocyanidins that appear to drive some of these metabolic and cognitive benefits.
Whyte, A.R., Rahman, S., Bell, L. et al. Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry. Eur J Nutr (2020).
Bell L, Lamport DJ, Butler LT, Williams CM. A study of glycaemic effects following acute anthocyanin-rich blueberry supplementation in healthy young adults. Food Funct. 2017;8(9):3104-3110. doi:10.1039/c7fo00724h