Blueberries and other dark berries contain a relatively high amount of health-supportive compounds. These include anthocyanins, a group of flavonoids that appear dark blue or purple, which have been shown to support cellular health, a healthy response to oxidative stress, and mitochondrial health.
Anthocyanins have also been shown to support vascular health. Results from a randomized control trial indicate that supplementation with blueberry for 1 month increased certain parameters related to endothelial function, including flow-mediated dilation. Improvements in 24-hour ambulatory systolic blood pressure were also observed.
Due to and beyond the potential supportive role of blueberries for vascular and cellular health and the response to oxidative stress, they may also support cognitive health and healthy aging. A clinical trial involving adults aged 68 years explored the changes to cognitive function and brain imaging in the presence of blueberry supplementation. The treatment group received a daily equivalent to one cup (approximately 148 g) of whole blueberries daily for 16 weeks. Results of functional MRI imaging showed increases in signaling in several brain regions in the treatment group, whereas the placebo group experienced decreased activation in certain brain regions.
A recently published randomized, double-blind, placebo-controlled trial explored the efficacy of blueberry supplementation in individuals aged 50 to 65 years with subjective cognitive decline. This 12-week intervention period involved daily supplementation with the powdered equivalent of one-half cup of blueberries. Study measurements included pre- and post-study cognitive evaluations relating to long-term memory, executive function, and mood. Biomarkers related to mitochondrial function and glucose metabolism were also assessed.
Study results indicate that the treatment group reported fewer memory complaints associated with forgetfulness and memory encoding difficulties. The treatment group also experienced a trend for enhanced mitochondrial uncoupling in peripheral platelets. Significant improvements in fasting insulin at the end of the treatment period were observed as compared to a placebo, independent of dietary changes. However, other changes to metabolic parameters, including fasting glucose and calculated insulin resistance were not observed in a between group comparison.
Drawbacks to this study include a small sample size, high attrition rate, and relatively short treatment period. In addition, self-reported assessment of memory may not accurately reflect cognitive changes. Still, results indicate that further studies may elucidate the potential protective role of blueberries in cognitive function.
Neurodegeneration is a complex process involving risk factors, such as age, genetics, cardiovascular disease, diabetes, and certain vitamin deficiencies. Blueberries and other dark berries may support brain health and healthy aging.
By Colleen Ambrose, ND, MAT