This systematic review of trials found that resveratrol supplements do not improve the results of tests that indicate risk of heart disease, including levels of blood pressure, blood glucose, cholesterol or C-reactive protein.
Resveratrol is found naturally in red grapes, other fruits, and nuts. Some researchers think resveratrol in red wine may lower the risk of cardiovascular disease in moderate drinkers, as seen in France. Resveratrol is currently available to buy as a supplement. This review aimed to find out whether resveratrol supplementation might help reduce cardiovascular disease risk markers. The findings suggest they don’t.
Why was this study needed?
Cardiovascular disease is a very common and serious problem in the UK. It causes a quarter of deaths in the UK, and an estimated seven million people are currently living with it. Being physically active and eating healthily lowers the risk of cardiovascular disease. The researchers wanted to see if taking a resveratrol supplement would also reduce the risk. Past trials have given contradictory findings and a 2013 systematic review of seven trials and 236 participants gave inconclusive results. The aim of this larger, more up to date systematic review, was to better understand whether resveratrol supplements improve markers of cardiovascular disease risk.
What did this study do?
This was a systematic review and meta-analysis of randomised controlled trials involving participants taking purified or standard-strength resveratrol supplements. Trial participants took reservatrol supplements for between 2 and 12 months, at doses ranging between 8 mg/day to 1500 mg/day. Trials were included only if they measured a blood protein called C-reactive protein (CRP), which is raised when there is inflammation in the body, including in cardiovascular disease. Other tests for cardiovascular disease risk included: cholesterol level, blood pressure and blood glucose. Studies were excluded for reasons such as using a low strength of resveratrol (below 5mg per day) or for using extracts with variable or unknown strength, such as in grape juice.
The results of 10 trials were pooled in a meta-analysis. The systematic review was rigorously carried out which provides confidence in the results, although the RCTs were relatively small in size.
What did it find?
- The systematic review found 10 relevant RCTs from around the world. They included 600 participants and were rated as moderate to high quality.
- Overall, taking resveratrol supplements was linked to a lower average CRP level (-0.144 mg/l) but this was not statistically significant (95% confidence interval -0.968 to 0.680).
- Most trials measured cholesterol and half measured blood pressure. There was no significant effect of taking resveratrol supplements on cholesterol or blood pressure.
What does current guidance say on this issue?
There is no guidance available on resveratrol supplementation. Neither NICE public health guidance on prevention of cardiovascular disease for the population (2010), nor a NICE guideline on maintaining a healthy weight (2015), provides recommendations for the use of resveratrol.
NICE public health guidance on prevention of cardiovascular disease does make recommendations on what can be done to reduce risk in the population and there are well known steps that individuals can take to reduce their own risk, summarised in other NICE guidance on cardiovascular risk, cholesterol and blood pressure treatment.
What are the implications?
This study only looked at the effect of resveratrol on laboratory test results, not actual heart disease. Nevertheless there is nothing in the research on the test results that suggests this supplements of this dietary component might be protective against heart disease.
The messages about preventing heart disease are unchanged by this study. Stopping smoking, eating and exercising healthily and getting treatment for any raised blood pressure or cholesterol, remain the main things individuals can do. Adding resveratrol supplements won’t help.
Sahebkar A, Serban C, Ursoniu S, et al. Lack of efficacy of resveratrol on C-reactive protein and selected cardiovascular risk factors: results from a systematic review and meta-analysis of randomized controlled trials. International Journal of Cardiology. 2015;189:47-55.
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Sahebkar A. Effects of resveratrol supplementation on plasma lipids: a systematic review and meta-analysis of randomized controlled trials. Nutrition reviews. 2013;71(12):822-35.
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