Flavonoids in blueberries protect the heart

That’s the conclusion of a recent study (1) led by researchers at both the University of East Anglia in the UK and Harvard. Eating 150g of blueberries a day has a protective effect on the cardio-metabolic system due to the flavonoids naturally present in these small berries.

Metabolic syndrome: a major risk factor for cardiovascular disease

The research team were investigating metabolic syndrome, a problem which now affects a third of all adults in the West. An individual is said to have metabolic syndrome if he or she has at least three of the following five cardiovascular risk factors: high blood pressure, low levels of ‘good’ cholesterol, elevated triglyceride levels, high blood sugar and excess abdominal fat (large waist circumference).

Metabolic syndrome significantly increases the risk of heart disease, stroke and type 2 diabetes, and often requires prescription drugs to treat the accompanying symptoms. According to the results of this study, eating 150 grams (a small bowl) of blueberries a day was shown to have a clear protective effect. It reduced arterial stiffness and improved vascular function in general, lowering cardiovascular risk by 12-15% in those with metabolic syndrome!

The heart-protective effect of blueberry anthocyanins

Blueberries’ heart benefits lie in the anthocyanins found at high concentrations in this tiny fruit. Anthocyanins are the natural pigments that give these berries their characteristic blue colour. In fact, they’re responsible for the red-violet-blue plant pigmentation of many fruits, flowers, and leaves. For example, the red colour of grapes (and therefore wine) is down to anthocyanins! They are part of the large family of flavonoids – the polyphenols found in many plants which are widely-recognised for their health benefits.

What roles do blueberry flavonoids play in the body?

The presence of anthocyanins and other flavonoids such as quercetin, catechins and resveratrol, means that blueberries offer a variety of exceptional benefits, hence their ‘superfruit’ status:

• they are antioxidants: by playing an active role in fighting free radicals, they form part of the first line of defence against cellular ageing and the development of cancer;
• they are anti-inflammatories, and promote healthy immune function;
• they are anti-bacterial, with protective effects against urinary infections, periodontitis, diarrhoea…;
• they help prevent brain damage as a result of a stroke;
• they reduce the risk of erectile dysfunction, especially when consumption is combined with regular exercise;
• they promote healthy development of brain function in children ;
• they help combat age-related cognitive decline: regular, high consumption of blueberries positively affects brain activity related to cognitive function in elderly people, particularly memory;
• they may have a protective effect on the retina, and improve night vision in particular.

The study’s authors therefore recommend that alongside a balanced diet, we should be consuming blueberries on a regular basis in order to benefit from their remarkable properties … bring on the blueberry harvest!

Reference
(1) P. J. Curtis,V. van der Velpen, L. Berends, A. Jennings, M. Feelisch, M. Umpleby, M. Evans, B. O. Fernandez, M. S. Meiss, M. Minnion, J. Potter, A. Minihane, C. D. Kay, E. B. Rimm, A. Cassidy. Blueberries improve biomarkers of cardiometabolic function in participants with metabolic syndrome—results from a 6-month, double-blind, randomized controlled trial. American Journal of Clinical Nutrition. Vol 109, pp 1535–1545, 2019.