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Scientists look into new functional ingredient in red wine

2019-07-08 16:24 Monday

Researchers in the UK have released the findings of a study which looked at resveratrol, a key organic component found in red wine – often touted for its health properties – to judge its effects on cardiovascular activity in mice.


For more than 10 years, scientists have been exploring links between resveratrol and lower blood pressure.

The study was conducted by researchers from King's College London and published in the American Heart Association's medical journal Circulation, and partly funded by the British Heart Foundation.

The scientists tested resveratrol on lab mice demonstrating high blood pressure, and looked at its effects at the molecular level. They found the chemical lowered blood pressure in the mammals, consistent with prior studies. But the way in which it did so was met by some as a surprise.

The study's researchers wrote in one statement: "We showed that, under conditions that reflect heart and circulatory diseases, resveratrol acts [as an] oxidant to lower blood pressure." What that means is, they saw that resveratrol added oxygen to proteins, thus triggering "vasorelaxation," so the blood vessels expanded, allowing for the blood pressure in the mice to fall.

The finding is interesting in terms of dietary structure because resveratrol is often praised for its properties as an antioxidant – essentially, the opposite of what was described in the latest study. Antioxidants have long been lauded because theoretically they help defend your cells from being damaged by potentially harmful molecules known as free radicals that trigger oxidative stress in cells.

Many functional foods are marketed as antioxidants and there is a large demand for their use. Antioxidant dietary supplements typically contain a mixture of vitamins A, C, and E, and their market entry has been touted by senior nutrition brands in the anti-aging category, as well as those in the sports nutrition and disease prevention sectors.

Antioxidant molecules protect against the harmful effects of oxidation. In the human body this is the breakdown of oxygen molecules caused by everyday occurrences such as exercise, metabolizing food and external factors such as exposure to pollutants in the air.

Those chemical reactions generate free radicals, which can lead to aging, inflammatory diseases and even cancer.

"Free radicals are uncharged molecules, which are highly reactive because they have an odd number of electrons," Ginger Hultin, a Seattle-based registered dietician and spokesperson for the Academy of Nutrition and Dietetics, explains.

"They can damage the outside of cells, or cellular membranes, as well as DNA, which is why we don't want too many of them bouncing around."

As is commonly thought, antioxidants can prevent this damage by lending their own electrons to stabilize the free radicals. "There are a lot of different types of free radicals, so the body needs a lot of different types of antioxidants to quench them," Hultin says.

But the new study suggests resveratrol and other "antioxidants" may actually help clinical health by adding oxygen. "Our findings question the idea of ‘antioxidants,'" the researchers wrote. "We think this might be the same story for many other drugs and compounds we currently think of as antioxidants."

This discovery could lead to a shift in the understanding of how resveratrol works, and the researchers believe their findings could someday be used to develop a new class of high blood pressure drugs for humans, or to develop new functional ingredients and functional foods.

Having a high blood pressure is one of the main causes of contracting life-threatening conditions such as heart attacks and strokes. According to the Centers for Disease Control and Prevention, it's experienced by roughly 1 in 3 adults in the U.S., whilst gobally the figure rises to about 40% of adults over 25.

However, to replicate the same levels of resveratrol used in the study using normal foodstuffs, a person would have to drink hundreds of bottles of wine a day. That is why a derivative or extract of the compound would need be produced. It's a good idea to reduce not increase your wine intake to that level.

Meanwhile, others are sceptic of the report for different reasons. Roger Corder, emeritus professor of experimental therapeutics at Queen Mary University of London, told Science Media Centre that the study's mouse experiment showed blood pressure effects that "are quite small. So I am astounded this paper made it through the referee process."

It is more likely that any blood pressure lowering effects were owing to the "very high concentrations of resveratrol being used rather than any relevant biological effect," said Corder.

Another commentator concluded: “On its own, drinking red wine is not going to help tackle hypertension; losing weight, taking regular exercise and lowering your stress levels are three of the best ways to do this."

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