Resveratrol case: investigation continues
Red wine has stopped prolonging life
Kirill Stasevich, "Science and Life" based on LiveScience – Debunked: Red Wine Antioxidant Won't Help You Live Longer.
Many of us have heard that red wine helps to stay healthy and prolongs life. It is believed that the component of red wine that is responsible for its beneficial properties is resveratrol, a protective molecule that some plants synthesize in response to infection. This substance is being investigated in the most thorough way, however, despite the initial optimism, it was not possible to get unambiguous results with resveratrol, and the adventures of this molecule in modern biology may well pull on a small, but extremely confusing detective series.
In animal experiments, resveratrol demonstrated a variety of positive properties, suppressing inflammation and oncological processes and increasing life expectancy. As an example, the study of Alirio Mendelez (Alirio J. Melendez) can be cited: He and his colleagues published an article in FASEB Journal in 2009 in which they described the strongest anti-inflammatory effect of resveratrol. The researchers attributed this effect to the antioxidant properties of the molecule. Then in 2011, experts from Maastricht University showed that resveratrol in the form of a dietary supplement normalizes metabolism in overweight men (these data were published in 2011 in Cell Metabolism). The following year, the Journal of Physiology published an article by Jason Dyck and his colleagues from the Canadian University of Alberta, in which researchers wrote that resveratrol increases physical performance in rodents.
These are just some examples of studies describing the positive properties of resveratrol. But in the same 2012, the opposite work appeared: scientists from Washington University in St. Louis reported from the pages of Cell Metabolism that resveratrol in the form of a dietary supplement does not increase insulin sensitivity (that is, it does not help protect against type 2 diabetes), does not reduce the risk of heart disease and does not increase the duration of life. This study was conducted not with rodents, but with people, although the work could not boast of significant statistics.
The confusion around resveratrol has been added by studies in which scientists have tried to uncover the molecular mechanism of its work. In 2006, a link was shown between it and the protein sirtuin – and sirtuin, I must say, was called for some time almost "the source of eternal youth", its level allegedly increased with a low-calorie diet (and under the influence of resveratrol), and this was accompanied by a slowdown in aging and an increase in life expectancy. However, troubles soon fell on sirtuin: in 2011, data were obtained that an increase in the level of this protein is only a side effect of the work of completely different genes, and its level does not affect life expectancy with aging by itself. At the same time, doubts appeared about the ability of resveratrol to interact with the "protein of eternal youth".
But after that, the situation changed once again: David Sinclair from Harvard (the one who first linked resveratrol with sirtuin) published an article in Science a year ago, in which he cited evidence of direct interaction of one with the other. Shortly after that, researchers from Washington University in St. Louis, led by Shin-ichiro Imai, published their data that sirtuin still delays old age (although for this it needs to be in certain areas of the hypothalamus, the main endocrine regulator of the body). And this means that resveratrol can also affect life expectancy, since it still interacts with sirtuin. And finally, in February of this year, the journal PNAS published an article by Guido Kroemer from the National Institute of Health and Medical Research of France (INSERM), in which he and his colleagues described the anti–oncogenic effect of resveratrol - it turned out that its molecules can kill cells in which there was a multiplication of the chromosome set and which because of this, it is very likely that the growth of a malignant tumor can be triggered.
However, apparently, the next bright streak for resveratrol is ending again. The journal JAMA Internal Medicine published an article by Richard D. Semba from Johns Hopkins University, which claims that there is no increase in life expectancy from resveratrol.
What is the peculiarity of this new job? Firstly, Richard Semba and his colleagues worked with people, secondly, the observations lasted nine years, and thirdly, the scientists did not use resveratrol dietary supplements, but assessed the natural difference in the level of this substance in the diet of the participants of the experiment. The study involved about 800 people, aged 65 years and older, who lived in the Chianti region of Italy, where red wine has been drunk for a long time and in sufficient quantities. The level of resveratrol metabolic products in their urine was measured, and according to this they were divided into four groups. Then, for nine years, as it was said, they monitored the well-being of the study participants, at the same time regularly checking the level of resveratrol consumed. There were no changes in the diet at the same time, each person ate and drank the same and in the same amount as before.
As a result, the authors concluded that resveratrol does not affect either the level of probability of cardiovascular diseases or the likelihood of developing cancer. And most importantly, it did not affect life expectancy in any way: those who received a lot of resveratrol with food died on average at the same time as those who received little of it. That is, over the nine years of observation, the number of study participants decreased equally in all groups.
These results now need to be somehow reconciled with others who say exactly the opposite things. Of course, if we see the effect of resveratrol in an experiment on animals or on cell culture, then everything can be blamed on the fact that a mouse or a cell culture there is quite far from a human. On the other hand, there is evidence that if red wine is present in the diet, then a person really has every chance to live longer than if he did not drink red wine. (It is worth noting that resveratrol is found not only in red wine, but also in grapes, other fruits, dark chocolate, nuts, etc.) Of course, it may be that these dietary data sin with some inaccuracies, but, on the other hand, there may be other substances in wine, chocolate, and nuts, whose beneficial effect is partly attributed to resveratrol.
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