No matter what age you are at, you may want to have an optimum cognitive function. A child may need better memory to recall what learned in class, and an older person may want to keep the ability to calculate the retirement spending. How to maintain and improve cognitive function and memory is one of the frequently asked questions. Whenever I answer this question, eat blueberries is normally the first thing that I tell someone.

 

    Blueberries are a rich source of polyphenolic compounds, particularly anthocyanins that are responsible for the fruit’s deep purple and blue color. These blueberry-derived polyphenols possess multiple properties that may mediate cognitive performance and neurodegeneration. Blueberries were mentioned previously in Purple Foods Rich in Anthocyanins Can Improve Cognitive Function.

 

    A group of scientists was interested in blueberries and they conducted multiple studies on the effect of a single dose of blueberry on cognitive function in different age groups from school-aged children to middle-aged adults. Whyte and Williams (1) first reported on the significant improvements in 8–10-year-olds’ word recall performance for both short and long delays at 2 hours post-consumption of a 200 g fresh blueberry drink (143 mg anthocyanins).

 

    Barfoot et al. (2) conducted a randomized study in 54 children aged 7–10 years who received either a 200 ml wild blueberry drink (253 mg anthocyanins) or a matched placebo on executive function and short-term memory. Consumption of wild blueberry drinks was found to significantly improve memory and attentional aspects of executive function. The children who drank blueberry drink had significantly quicker reaction times when compared to placebo participants on memory and recall trials, without cost to accuracy. Blueberry drink participants showed enhanced verbal memory performance, recalling more words than placebo participants on short delay and memory acquisition measures at 2 hours post-consumption (p<0.05). This blueberry drink was equivalent to 240 g or 1½ cups of fresh blueberries, a dose that can provide acute cognitive benefits in children. Flavonoid-rich products are beneficial for healthy brain function, particularly during critical developmental periods.

 

    In another study (3), the cognitive performance of 7–10-year olds was examined at baseline, 1.15 hours, 3 hours, and 6 hours post-consumption of two wild blueberry interventions: a 30 g wild blueberry drink (253 mg anthocyanins) and a 15 g wild blueberry drink (127 mg anthocyanins), compared to a sugar-matched placebo drink. Significant wild blueberry-related improvements were observed for word recognition at every time point. Additionally, significant improvements in accuracy on a cognitively demanding executive function task were observed at 3 hours post-consumption of the 30-g wild blueberry drink. These findings highlight the potential for wild blueberry interventions to enhance word recall and recognition performance, as well as improving executive function up to 6 hours post-consumption in 7–10-year-olds. At this age, children experience a spurt in frontal lobe growth thought to coincide with enhanced executive functions and the progression of cognitive abilities, a phase of cognitive development where blueberry supplementation may be particularly beneficial.

 

    To explain the dosing of this study (3) for easier understanding: the study participants were given a drink containing either 15- or 30-g freeze-dried wild blueberries or a placebo treatment. Each participant completed three-dose treatments with a 7-day washout between treatments. The 30-g wild blueberries freeze-dried dose was equivalent to ~240 g fresh wild blueberries (108 kcal) which contained 253 mg anthocyanins, while the 15-g dose was equivalent to ~120 g fresh wild blueberries which contained 127 mg anthocyanins. Both the placebo and 15-g wild blueberries treatments had fructose, sucrose, and vitamin C added to match levels of these nutrients with the 30-g wild blueberries treatment.

 

    These scientists recently conducted a randomized, double-blind, cross-over study in 35 individuals aged 40-65 years (4). Study participants consumed a breakfast meal plus a wild blueberry beverage consisted of 25 g freeze-dried whole wild blueberry powder (equivalent 1-cup fresh weight wild blueberries) or matched placebo beverage. Participants completed cognitive tasks and had blood drawn before and at regular intervals for 8 hours after each meal/treatment.

 

    The results indicated wild blueberry intake in cognitively healthy middle-aged individuals improved both episodic memory and executive function performance, particularly in demanding tasks and cognitive fatigue. Wild blueberries also improved glucose and insulin responses to a meal. Metabolic responses to treatments were different during the first 120 minutes post-meal with significantly lower glucose and insulin recorded for wild blueberries in comparison to placebo (4).

 

    Anthocyanins are a class of flavonoid polyphenols that are strongly represented in berry fruits such as blueberries, blackberries, and strawberries. Previous animal studies have reported that ingested anthocyanins appear in greater concentrations in parts of the brain associated with memory and have been associated with cognitive performance. Blueberry consumption had been reported to boost neuroplasticity in structures such as the hippocampus and frontal cortex through the stimulation of trophic factors including brain-derived neurotrophic factor (BDNF) and Insulin-like growth factor 1 (IGF-1). Blueberry supplementation not only had an influence on the cognitive capabilities and development of children, but also could reverse age-related decline in cognitive and motor function and enhance neural resilience, cerebral blood flow, and endothelial protection (5).

 

    Thinking back, seeing my son and my daughter stopping at the refrigerator often looking for blueberries and later getting into good colleges may well be related. I am thinking perhaps if I live on a blueberry farm, my cognitive function can be better preserved. :-)

Reference list:

1. Whyte A.R., Williams C.M. (2015). Effects of a single dose of a flavonoid-rich blueberry drink on memory in 8 to 10 y old children. Nutr 31(3):531–534.

2. Barfoot, K.L., May, G., Lamport, D.J., Ricketts, J., Riddell, P.M., Williams, C.M. (2018). The effects of acute wild blueberry supplementation on the cognition of 7–10-year-old schoolchildren. Eur. J. Nutr.

3. Whyte A.R., Schafer G., Williams C.M. (2016). Cognitive effects following acute wild blueberry supplementation in 7-to 10-year old children. Eur J Nutr 55(6):2151–2162.

4. Whyte, A.R., Rahman, S., Bell, L., Edirisinghe, I., Krikorian, R., Williams, C.M., Burton-Freeman, B. (2021). Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry. Eur J Nutr. 60(3):1521-1536.

5. Travica, N., D’Cunha, N. M., Naumovski, N., Kent, K., Mellor, D. D., Firth, J., … Marx, W. (2019). The effect of blueberry interventions on cognitive performance and mood: a systematic review of randomized controlled trials. Brain, Behavior, and Immunity.