The naturally occurring polyphenol resveratrol may have a role in preventing bone loss and fractures in older women, an Australian trial has suggested.

In a randomised controlled trial involving 125 healthy postmenopausal women, researchers at Newcastle University, NSW, showed that daily supplementation with resveratrol, which can act as a phytoestrogen, slowed the loss of bone mineral density in the spine and femoral neck compared to placebo.

The Resveratrol for Healthy Aging in Women (RESHAW) trial found that after 12 months of taking the supplement (75 mg twice daily) there were positive effects on bone density in the lumbar spine (+0.016 ± 0.003 g/cm2) and neck of femur (+0.005 ± 0.002 g/cm2), compared to placebo.

The effects were accompanied by a 7.24% reduction in C‐terminal telopeptide type‐1 collagen levels, a bone resorption marker.

The trial, which had a 24-month crossover design, showed that in parallel analysis there was a 1.0% decline in femoral neck BMD in the placebo group, in line with the annual rate of decline seen in other Australian studies of the general population of postmenopausal women. In the resveratrol group, the rate of decline in femoral neck BMD from baseline was 0.34% after 12 months of supplementation, “suggesting the potential to slow the decline through regular resveratrol supplementation.”

The annual change in lumbar spine BMD from baseline was −0.55% in the placebo group, whereas  there was a + 0.46% increase in BMD from baseline in the resveratrol group.

According to the study investigators led by Dr Rachel Wong, the increase in BMD in the femoral neck resulted in an improvement in T ‐score (+0.070 ± 0.018) and a reduction in the 10‐year probability of major and hip fracture risk.

They noted that the resveratrol-induced increases in femoral neck T‐score correlated with increases in measures of cerebrovascular responsiveness (CVR), suggesting the mode of action was mediated by increased microvascular perfusion in bone.

The trial also found that the bone protective effect of resveratrol was greater in women with poor bone health biomarker status and in women who supplemented with vitamin D plus calcium.

The researchers said resveratrol was thought to have properties of a phytoestrogen and had been shown in animal models to promote osteoblast‐mediated bone formation and inhibit osteoclast‐stimulated bone resorption via similar mechanisms to genistein.

Its effects were also thought to be mediated by vasodilation via oestrogen receptors to improve microvascular perfusion, and it has also been studied for benefits on for cerebrovascular function and cognitive function.

“Regular supplementation with 75 mg of resveratrol twice daily has the potential to slow bone loss in the lumbar spine and femoral neck, common fracture sites in postmenopausal women without overt osteoporosis.,” they concluded.

However they cautioned that further RCTs are needed to test whether resveratrol in combination with vitamin D and calcium will improve the vascular and bone health of older women.

The findings are published in the Journal of Bone and Mineral Research.