Red wine good, bad, yes, no? Who should we believe?

It wasn't all that long ago that there was great joy among lovers of red wine and chocolate. The announcement that these two treats (or necessities, depending on the person) could be good for you was very welcome news.

The basis of this news was the belief that resveratrol, a substance found in products like red wine and chocolate, could be cardioprotective. Studies such as this 2009 one published in the Journal of Cardiovascular Pharmacology, concluded:

Both wines and grapes can attenuate cardiac diseases such as atherosclerosis and ischemic heart disease. Recently, wine was also found to increase life span by inducing longevity genes. It appears that resveratrol and proanthocyanidins, especially resveratrol, present in grapes and wines play a crucial role in cardioprotective abilities of grapes and wines.

Another example is this article, which is a review of studies done on the effects of resveratrol, published in 2011 in the journal Molecular Nutrition & Food Research, in which the authors wrote:

The emerging data from human clinical trials confirms what the past decade of in vitro and laboratory animal models have suggested; resveratrol has considerable potential to improve health and prevent chronic disease in humans. We believe the evidence is sufficiently strong to conclude that a single dose of resveratrol is able to induce beneficial physiologic responses, and that either weeks or months of resveratrol supplementation produces physiologic changes that are predictive of improved health, especially in clinical populations with compromised health. However, it is not yet certain if long-term resveratrol supplementation will maintain these physiologic benefits to ultimately impact the incidence of chronic disease or extend lifespan, and the small number of human clinical trials remains dwarfed by the thousands of basic science experiments.

Not all researchers got on the resveratrol bandwagon though. In 2005, the journal Circulation published an article that wasn't so positive about the whole idea. While admitting that the research was pointing to benefits, the authors were cautious about recommending red wine:

Despite considerable data from epidemiological studies and strong suggestions from experimental research, the evidence is still insufficient to encourage patients who do not drink to start consuming red wine as part of a strategy to protect against atherosclerosis.

And now, new research is saying, nope -that resveratrol stuff isn't true. Yet another study, this time published recently in JAMA Internal Medicine said that, resveratrol in combination with a Western diet did not increase lifespan or decrease the incidence of illnesses, such as heart disease and cancer.

This was a small study, if anyone is looking for hope that it may not be really true. There were only 783 subjects who were followed over a course of nine years.

So before we start closing our wine cellars and tossing our dark chocolate, maybe we should do what is recommended for most things - consume them in moderation unless we're told by our physician to abstain.