When we think of brain foods, we usually think of fatty fish because of its high omega-3 content, widely known to improve cognition. Yet, another food has been stealing the spotlight for its cognitive-boosting benefits: blueberries.
Blueberries, as it turns out, have far greater benefits than simply making pancakes and muffins even more palatable—they might also rev up your brain. The flavonoids present in blueberries have been linked to improved cognitive performance and to reduced neuronal stress.
One study published in 2016 looked at the effects of freeze-dried wild blueberry supplementation on children aged 7 – 10 years completing a range of cognitive tasks. The children were given a drink containing either 15 or 30 g freeze-dried wild blueberries or a placebo treatment. To put this into perspective, 30 g of freeze-dried wild blueberries is the equivalent of 240 g fresh wild blueberries, while 15 g is equivalent to 120 g fresh wild blueberries.
Each participant completed three treatment days with a 7-day washout between treatments. The study found overall improvements in cognitive function, with the best change from baseline performance associated with the 30 g treatment, intermediate performance with the 15 g treatment, and least effective performance with the placebo treatment. Particularly, children in the 30 g group were better at word acquisition and word recognition and had a greater ability to overcome response interference effects.
Another study looked at the effects of blueberry supplementation on cognition and mobility in a different population: healthy older adults between the ages of 60 and 75. Participants consumed 12 g of either a lyophilized, standardized blend of a specific blueberry powder or a color-matched blueberry-flavored placebo powder, twice a day, for 90 days (24 g/day, equivalent to 1 cup of fresh blueberries).
The study found that 3 months of blueberry supplementation, which can easily be achieved at home, resulted in reduced repetition errors during word list recall and increased accuracy during task switching (which may reflect improved executive control) among healthy older adults.
These beneficial effects of blueberries have been largely attributed to their relatively high flavonoid content, in particular, anthocyanins. However, blueberries are also rich in other powerful compounds such proanthocyanidins, chlorogenic acids, and flavonols that play just as big of a role in promoting health.
Proanthocyanidins have been shown to have anti-carcinogenic properties while chlorogenic acids have powerful antioxidant and anti-inflammatory properties associated with a reduced risk of cardiovascular disease, type 2 diabetes, and Alzheimer’s disease. Flavonols also possess cardioprotective and anti-carcinogenic, as well as potentially ergogenic properties.
One study looked at the polyphenol metabolite concentrations in plasma and urine following the consumption of blueberries either acutely or over time. Specifically, the study sought to elucidate whether chronic intake of blueberry had any impact on the profile and concentration of phenolic metabolites.
Volunteers consumed 11 g of freeze-dried blueberry powder (equivalent to 100 grams of fresh blueberry) dissolved in water twice daily. A total of 61 and 62 metabolites were found in plasma and urine, respectively, of which 19 were found to increase at 2h post consumption and 38 after 30 days of daily supplementation. These metabolites included benzoic acids, phenylacetic acids, propionic acids, pyrogallols, catechols, hippuric acids, cinnamic acids, flavonols, and valerolactone derivatives.
The study concluded that blueberry polyphenols are absorbed and extensively metabolized by phase II enzymes and by the gut microbiota, leading to a whole array of metabolites that may be responsible for the beneficial effects observed after blueberry consumption.
In other words, we can’t single out a specific compound as being the superstar; rather, the synergistic effects of the combination of phytonutrients and its subsequent metabolites, acutely and over time, serve to contribute to blueberries’ healthful profile.
Thankfully, blueberries can be easily incorporated in your daily meals. You can throw them in a smoothie or yogurt, use them as topping for (healthy) pancakes or oatmeal, or simply eat them by the handful as a snack. With so many benefits from heart to brain, making blueberries part of your diet should definitely be a no-brainer.