Eating a handful of blueberries daily lowers blood pressure and improves vascular and cerebral blood flow leading to better cardiovascular and cognitive health, according to a recent study published in the American Journal of Clinical Nutrition.¹

Researchers from the UK, Germany and Portugal collaborated in this randomised, double blind, placebo-controlled trial to evaluate the beneficial effects of blueberries. For this they enrolled 61 healthy older adults aged 65-80 years, who were randomly assigned to receive a drink constituted from 26g of freeze-dried wild blueberry powder (equivalent of 178 g of whole blueberries containing 302 mg anthocyanins) or a matched placebo but with no anthocyanins for a duration of 12 weeks.

After 12 weeks, there was a substantial increase in the flow-mediated dilation (FMD), a measure to evaluate endothelial function, in the participants in the blueberry group compared to the placebo group (0.86%). The 24-hour ambulatory systolic BP also decreased by 3.59 mmHg. No difference was noted for arterial stiffness and blood lipids between the two groups. Participants who consumed blueberries showed enhanced “immediate recall on the auditory verbal learning task, alongside better accuracy on a task-switch task”. But no improvement was seen in delayed recall. Subjects in the blueberries group also exhibited higher total 24-hour urinary polyphenol levels compared to placebo after 12 weeks.

These findings demonstrate the cardio- and neuroprotective effects of blueberries. The daily intake of 178 gm of fresh blueberries in this study lowered blood pressure and improved blood vessel function, which also boosted cognitive function in older adults in the form of improved executive function and better short-term memory.

The beneficial effects of blueberries have been attributed to their anthocyanin content. Anthocyanins are red, blue or purple pigments found in fruits and vegetables and are potent antioxidants. Additionally, they have antidiabetic, anticancer, anti-inflammatory, antiangiogenesis, antimicrobial and anti-obesity properties. They also play an important role in maintaining good vision.² Other sources of anthocyanins are purple vegetables, raspberries, strawberries, and red grapes.

References

1. Wood E, et al. Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older males and females: a double-blind randomized controlled trial. Am J Clin Nutr. 2023 Mar 25;S0002-9165(23)46300-9. doi: 10.1016/j.ajcnut.2023.03.017.
2. Khoo HE, et al. Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits. Food Nutr Res. 2017 Aug 13;61(1):1361779. doi: 10.1080/16546628.2017.1361779