Vancouver, B.C. – Resveratrol increased cerebral blood vessel dilation in a small study of adults with type 2 diabetes mellitus, suggesting a possible role for slowing disease-related cognitive decline, according to investigators from the University of Newcastle (Australia).
Dr. Rachel Wong
Type 2 diabetes impairs the ability of blood vessels to dilate effectively in response to demand, which may impact mental performance and perhaps contribute to the greater risk of dementia in people with the disease, according to investigator Rachel Wong, Ph.D., a biomedical researcher at the university.
Her team previously demonstrated that resveratrol – a polyphenol found in berries, nuts, grapes, and, famously, red wine – improves vasodilation in the systemic circulation, so they wanted to see if would do the same in the brain (Nutr Metab Cardiovasc Dis. 2011 Nov;21(11):851-6).
Thirty-six dementia-free adults with type 2 diabetes took one of three doses of synthetic resveratrol – 75 mg, 150 mg, and 300 mg – or placebo at weekly intervals. Before and about an hour after each dose, the patients briefly breathed carbogen gas (95% oxygen, 5% carbon dioxide) to induce hypercapnia and subsequent cerebral vasodilation. Transcranial Doppler ultrasound was used to assess the change in blood flow in the middle and posterior cerebral arteries before and after dosing.
The percentage change in mean blood flow velocity in the middle cerebral arteries increased after all three doses of resveratrol, but not after placebo. The 75 and 300 mg doses both increased flow velocity by about 10%, while the 150 mg dose increased it by about 6%. Meanwhile, the 75 mg dose was the only one to increase vasodilator responsiveness in the posterior cerebral arteries.
“This is the first clinical evidence that resveratrol can enhance vasodilator responsiveness in people with type 2 diabetes. We are now investigating if regular supplementation can restore cerebral perfusion, and if that can attenuate the accelerated cognitive decline seen in this population,” Dr. Wong said.
They plan to test that with the 75 mg dose, the amount of resveratrol in about 30 liters of red wine. “I think it’s better to get it in the synthetic form,” she said.
The patients in the study were 68 years old on average, with a mean body mass index of 30 kg/m2. They had diabetes for about 10 years, and their mean hemoglobin A1c was 6.7%. The majority of subjects were on oral diabetes therapies; none of them was on insulin.
The investigators have no disclosures. The work was funded in part by the Australian National University and by DSM Nutritional Products, which provided the resveratrol.