The phytochemicals that give blueberries their blue color can significantly improve cardiovascular health, finds a new two part study. Dubbed "the silent killer" because it has no visible symptoms in its early stages, hypertension affects approximately 1 in 3 adults in the United States.
The condition puts a strain on the cardiovascular system, which in the long run may contribute to heart failure, stroke, and kidney failure. The National Institutes of Health (NIH) recommend that people with high blood pressure stay in control of the condition by eating healthfully, exercising, not smoking, and maintaining a healthy weight.
But should you eat anything in particular to keep your arteries healthy? In a previous Spotlight feature, we rounded up 16 foods that studies have suggested can improve cardiovascular health. Along with broccoli, spinach, pulses, and fish, berries may also reduce heart disease, due to their antioxidant polyphenols.
New research zooms in on the cardiovascular effects of blueberries and finds that anthocyanins — the phytochemicals that give blueberries their color — mediate the beneficial effects that this fruit has on the cardiovascular system. The lead author of the study is Ana Rodriguez Mateos, Ph.D., from the Department of Nutritional Sciences at King's College London, in the United Kingdom. The researchers published their findings in The Journals of Gerontology: Series A.
Rodriguez-Mateos and her colleagues recruited 40 study participants who were in perfect health and randomly divided them into two groups: One received a daily drink consisting of
200 grams (g) of blueberries, and another group received a control drink.
To examine the effects of the blueberries, the researchers took the participants' blood pressure and measured the flow-mediated dilation (FMD) of their brachial arteries.
FMD is a standard indicator of cardiovascular risk; it measures how much the brachial artery widens when blood flows at a higher rate.
In the second part of the study, the researchers compared drinking blueberries with drinking purified anthocyanins or control drinks that had concentrations of fiber, minerals, or vitamins equivalent to those in blueberries. The scientists noticed the beneficial effects of the blueberry drinks only 2 hours after the participants had consumed them. "Purified anthocyanins exerted a dose-dependent improvement of endothelial function in healthy humans, as measured by [FMD]," report the authors. The endothelium is a type of membrane inside the heart and blood vessels. It contains endothelial cells that help control the dilation and contraction of the arteries. Endothelial cells also help keep blood pressure in check and play a key role in blood clotting.
The authors conclude by saying that it is best to eat the whole fruit but most of the benefits can be achieved by taking the anthocyanins. I often supplement anthocyanins for patients with capillary fragility. They strengthen the endothelial wall, helping to reverse varicose veins and can prevent or even reverse phlebitis.
Blueberries should be a stable in your diet. Additionally, if you have hypertension, supplementation of anthocyanins or daily consumption of blueberries can be as effective as hypertensive medications like beta-blockers, calcium channel blockers and ACE inhibitors in reducing blood pressure.