May 20, 2014

Resveratrol: Does It Extend Lifespan and Help Prevent Heart Disease and Cancer?

Resveratrol – the plant-based antioxidant found in red wine and foods like chocolate and blueberries – has made headlines again. For years, it’s been touted as an effective anti-inflammatory agent in preventing cardiovascular disease and some types of cancer.

But a study published in the May 12 online edition of the New England Journal of Medicine suggests differently.

Scientists at Johns Hopkins University Medical School reviewed the records of 783 men and women -- 65 and older -- from Italy’s Chianti region, where people’s diets would likely be high in natural resveratrol from the area’s popular red wine.

Those researchers based their conclusions on the amounts of metabolized resveratrol present in study participants’ urine, figuring that the healthiest seniors would show the highest levels of resveratrol.

Said lead author Richard Semba:
We were initially surprised by the lack of any apparent protection against heart disease or cancer, and no association with lifespan. Since limited animal and cell studies suggested that resveratrol might have beneficial effects, I think people were quick to extrapolate to humans. In retrospect, this was really oversimplified. But there are still ongoing trials, so one must keep an open mind about possible benefits.

Of Mice and Men, Again
Semba identified the key weakness in the claims for resveratrol’s ability to prevent disease and extend lifespan: the lack of evidence ON PEOPLE. Science has established that plants produce the substance to combat fungal infection, ultraviolet radiation, stress, and injury.

In 2003, Dr. David Sinclair, now a professor of genetics at Harvard Medical School (and named this year by Time Magazine as one of the 100 most influential innovators in the world), demonstrated that resveratrol could boost cell survival and retard aging in yeast – later in mice, even – by activating a “longevity” gene, identified as SIRT1.

Over the past decade, we’ve learned other things about resveratrol, too… just not much about its effect on humans. It can:
  • prevent skin cancer in mice;
  • protect against high blood pressure, heart failure, and heart disease in mice;
  • improve insulin sensitivity, reduce blood sugar, and blunt obesity induced by a high-fat diet in rodents;
  • protect nerves and the brain in various lab animals.

A Thousand Glasses of Red Wine a Day?
There’s another problem with resveratrol studies to date. The doses administered to the animal subjects in these studies was much higher than what people would typically consume in their diets. In fact, according to Dr. Sinclair, we’d have to drink between 100 to 1,000 glasses of red wine to approximate the dosages that help improve health in rodents. Not exactly an option.

Sinclair doesn’t dispute studies that show positive effects on people from drinking red wine or eating chocolate or blueberries. He also cautions against despairing about resveratrol, and other similar substances. In fact, he reports that drug companies have created thousands of new synthetic molecules “that are up to a thousand times better than resveratrol. They prevent cardiovascular disease and neurodegeneration. They also extend lifespan in mice.”

Again, in mice.

As we might expect, companies have been quick to capitalize on the substance’s potential benefits for people. In fact, resveratrol supplements now represent a $30M business in America. Dr. Sinclair has been taking it for ten years. But we have no way of knowing – yet – what dosage is both safe and effective for humans. We also do not know the long-term effects of resveratrol use on humans.

To some extent, people using the substance are a bit like the mice who have been studied. The one big difference? The human users are not now being properly studied.

More Resveratrol Headlines
On May 3, the online journal Medical News Today reported that scientists have identified a mechanism by which resveratrol may impart positive health benefits.

Researchers from The Scripps Research Institute in Florida found that resveratrol blocks interleukin 6 (IL-6), a protein in the immune system that can trigger inflammation. Among other indications, elevated IL-6 levels have been associated with lowered survival rates for breast cancer patients.

Here’s the interesting part: resveratrol blocks interleukin – the inflammation trigger – by operating in concert with the body’s estrogen receptors. Science has shown that estrogen can hasten the growth of breast cancer tumors via receptors on the surface of cancer cells.

When resveratrol blocks IL-6, something else happens: estrogenic cell growth – the reproduction of cancer-causing cells, is deactivated. This discovery gives scientists another target – the estrogen receptor –for new drug development.

We’ve heard the ongoing debate about the effects of estrogen -- and estrogen replacement therapy -- on health.  It’s an issue that arises in this arena, too. Said Scripps lead researcher:
Estrogen has beneficial effects on conditions like diabetes and obesity but may increase cancer risk. What hasn't been well understood until now is that you can achieve those same beneficial effects with something like resveratrol. 
Now that we understand that we can do this through the estrogen receptor, there might be compounds other than resveratrol out there that can do the same thing, only better. 
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This “back and forth” about resveratrol – yes it does, no it doesn’t – is typical of research these days, as the most recent study calls into question the conclusions of the last study. I discussed that issue -- flawed results from the latest study -- in a recent post.

I've written about resveratrol before, and will -- no doubt -- again. For earlier comments, just enter "resveratrol" in the "search blog" box.


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