Resveratrol counteracts insulin resistance—potential role of the circulation

Pre-clinical data and human trials indicate that resveratrol supplementation may help to counteract diabetes. Several mechanisms of action have been proposed to explain its metabolic benefits, including activation of sirtuins and estrogen receptors (ER) to promote glucose transporter type-4 (GLUT4) translocation and increase glucose uptake. Resveratrol can also enhance vasodilator function, yet the possibility that this action might help to alleviate insulin resistance in type-2 diabetes mellitus has received little attention. In this brief review we propose that, by restoring impaired endothelium-dependent vasodilatation in insulin resistant individuals resveratrol increases blood perfusion of skeletal muscle, thereby facilitating glucose delivery and utilization with resultant improvement of insulin sensitivity. Thus, circulatory improvements by vasoactive nutrients such as resveratrol may play a role in preventing or alleviating insulin resistance.Rachel H. X. Wong and Peter R. C. How

Sustained cerebrovascular and cognitive benefits of resveratrol in postmenopausal women

Deficits in the cerebral microcirculation contribute to age-related cognitive decline. In a pilot study of postmenopausal women, we found that supplementation with a low dose of resveratrol, a phytoestrogen, for 14 weeks improved cerebrovascular and cognitive functions. We have since undertaken a larger, longer term study to confirm these benefits. Postmenopausal women aged 45-85 years (n = 129) were randomized to take placebo or 75 mg trans-resveratrol twice daily for 12 months. Effects on cognition, cerebral blood flow, cerebrovascular responsiveness (CVR) and cardiometabolic markers (blood pressure, diabetes markers and fasting lipids) were assessed. Compared to placebo, resveratrol improved overall cognitive performance (P < 0.001) and attenuated the decline in CVR to cognitive stimuli (P = 0.038). The latter effect was associated with reduction of fasting blood glucose (r = -0.339, P = 0.023). This long-term study confirms that regular consumption of resveratrol can enhance cognitive and cerebrovascular functions in postmenopausal women, with the potential to slow cognitive decline due to ageing and menopause.Jay Jay Thaung Zaw, Peter R.C. Howe, and Rachel H.X. Won

Postmenopausal health interventions: time to move on from the Women's Health Initiative?

Menopause is a critical period during which, without timely interventions, increased risks of cardiovascular and metabolic diseases, osteoporosis, sexual dysfunction and premature cognitive decline will contribute to diminished quality-of-life in women. Hormone therapy (HT) used to be the standard of care for managing vasomotor symptoms and prevention of chronic diseases until publication of the Women's Health Initiative (WHI) in 2002. Concerned about risks highlighted in WHI publications, many symptomatic women promptly ceased HT which resulted in increased vasomotor symptoms, osteoporosis-related-fractures and insomnia. Data from post-hoc WHI analyses and newer clinical trials consistently show reductions in coronary heart disease and mortality when estrogen therapy is initiated soon after menopause, whereas administration in later years and/or in combination with progesterone carries increased risks. However, no validated primary preventive strategies are available for younger postmenopausal women (60 years), risks associated with oral HT exceed benefits; however transdermal estrogen may offer a safer alternative and should be further evaluated. Alternative therapies such as phytoestrogens and non-hormonal prescriptions may be beneficial for older women or those who are unsuitable for HT. Long-term head-to-head comparisons of HT with alternative interventions are warranted to confirm their efficacy for chronic disease prevention.Jay Jay Thaung Zaw, Peter Ranald Charles Howe, Rachel Heloise Xiwen Won