A new study investigates whether an antioxidant commonly found in some wine and fruits has beneficial effects on the cardiovascular health of patients with diabetes.
Resveratrol is a natural compound that can be found in grapes, grape juice, red wine, and some types of berries – including blueberries and cranberries – as well as in peanuts and cocoa.
The compound is a polyphenol – that is, a class of plant-based chemical substances with antioxidant properties.
Some studies have suggested that polyphenols may have a protective role against heart disease by improving vascular function and regulating inflammation.
New research, presented at the American Heart Association's Arteriosclerosis, Thrombosis and Vascular Biology and Peripheral Vascular Disease 2017 Scientific Sessions in Minnesota, examined the effect of resveratrol on artery stiffness in people with diabetes.
The purpose of the study
With age, our arteries become less supple.
This may result in various adverse cardiovascular events, including increased blood pressure, coronary heart disease, and stroke.
As the authors of the new study explain, patients with diabetes show signs of premature aging of the arteries.
However, some animal studies have shown that resveratrol can reduce the stiffness of the aorta – the main artery in the human body that transports the blood away from the heart and into the rest of the body.
These studies revealed that resveratrol activates a gene called SIRT1, which can slow down the aging.
The existing research has motivated the team of scientists – led by Ji-Yao Ella Zhang, Ph.D., a postdoctoral fellow at the Whitaker Cardiovascular Institute at Boston University in Massachusetts – to investigate whether or not resveratrol has the same effect in humans.
Conclusions from the study
The standard method for measuring aortic stiffness is a test called the carotid-femoral pulse wave velocity (CFPWV) test.
In the new study, researchers used a CFPWV test to determine aortic stiffness in 57 patients with type 2 diabetes. On average, participants were 56 years of age and were considered obese according to standard body mass index (BMI) calculations.
In the beginning, the patients were administered daily doses of 100 milligrams of resveratrol for two weeks. This was then increased to 300 milligrams per day for a further two weeks.
The patients were also administered a matched, polyphenol-free placebo treatment for a total of four weeks, with a washout period of two weeks between treatments.
In the overall study group, no statistically significant changes were detected after administering resveratrol.
However, in a subgroup of 23 patients who experienced high arterial stiffness at study baseline, a 300-milligram per day dose of resveratrol seemed to decrease aortic stiffness by 9 percent.
Additionally, this effect correlated proportionally with the dosage: a 100-milligram daily intake of resveratrol reduced aortic stiffness by a smaller 4.8 percent. By contrast, aortic stiffness increased when the patients took the placebo treatment.
Helping more with diabetes
Resveratrol may be more beneficial to patients with diabetes than to healthy individuals
The study’s senior author, Dr. Naomi M. Hamburg, commented on the significance of the findings.
"This adds to emerging evidence that there may be interventions that may reverse the blood vessel abnormalities that occur with aging and are more pronounced in people with type 2 diabetes and obesity," Hamburg said in a press statement.
However, Hamburg – who is also chief of the vascular biology section at the Boston University School of Medicine in Massachusetts – cautions that resveratrol may not be as beneficial to people who do not have diabetes.
"The effect of resveratrol may be more about improving structural changes in the aorta, and less about the relaxation of blood vessels, and people with more normal aortic stiffness may not get as much benefit," she said.
The study’s lead author also weighed in on the findings.
"We found that resveratrol also activates the longevity gene SIRT1 in humans, and this may be a potential mechanism for the supplements to reduce aortic stiffness,” said Zhang. “However, the changes in this small and short-term study are not proof. Studies with longer treatment are needed to test the effects of a daily resveratrol supplement on vascular function."