Resveratrol has no benefit? Wrong!

Once again we have another study that supposedly shows no benefit to nutritional supplementation.(1) We are told that this should shut the book on the idea that resveratrol supplementation has any benefit. What about the hundreds of other studies that have shown cardiovascular, anti-ageing and other benefits?(3,4,5) And once again, we have a study did not show what the authors are claiming.

For one thing, this study did not even look at individuals who were taking supplements of resveratrol. And you should keep in mind that most of the studies that have shown a benefit to resveratrol supplements involved intake of levels many times greater than can be achieved through food sources. This study looked at metabolites of resveratrol in the urine of individuals who live in the Chianti region of Italy. It found no clear decreased risk of death in those who had higher levels of resveratrol metabolites in their urine. This paper notes that the resveratrol came from food, but the reason that this study looked at folks from Chianti is that they drink lots of red wine and the richest food source of resveratrol is from red wine. So what this study actually found is that those who drank alcohol most heavily did not have a lower risk of death. Heavy drinkers did not live longer–not much of a surprise! Maybe that is because the resveratrol had a protective effect, since you would have assumed that the heaviest drinkers would have an increased rather than a decreased risk of death.

Second, the levels of resveratrol achieved are much lower than the levels that have been shown in most studies to have an anti-cancer or longevity effect, such as increasing Sirt 1 gene activity.(2) Such levels require supplementation. The lowest dosage found to be beneficial in studies is 20 mg/day, which is equivalent to 41 glasses of red wine/day. Therefore even heavy drinkers of chianti would not approach these levels in their urine. And most studies showing positive benefits used dosages of 150-500 mg/day, an amount only attainable through supplements.

References:
1. Semba RD, Ferrucci L, Bartali B, et al. Resveratrol Levels and All-Cause Mortality in Older Community-Dwelling Adults. JAMA Intern Med. Published online May 12, 2014.
2. Walle T, Hsieh F, Delegge MH, Oatis JE, Jr., Walle UK. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metab Dispos. 2004;32(12):1377-1382.
3. Fernández AF, Fraga MF. The effects of the dietary polyphenol resveratrol on human healthy aging and lifespan. Epigenetics: official journal of the DNA Methylation Society. 2011;6 (7): 870–4.
4. Pace-Asciaka CR, Hahnb S, Diamandis EP, et al. The red wine phenolics trans-resveratrol and quercetin block human platelet aggregation and eicosanoid synthesis: Implications for protection against coronary heart disease. Clinica Chimica Acta. 1995; (235): 207–219.
5. Witte1 AV, Kerti1 L, Margulies DS, Flöel A. Effects of Resveratrol on Memory Performance, Hippocampal Functional Connectivity, and Glucose Metabolism in Healthy Older Adults. The Journal of Neuroscience, 4 June 2014, 34(23): 7862-7870.

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