In the final part of a special series on resveratrol, NutraIngredients looks at the science behind the ingredient. Is there nothing it cannot do?
In 2003, the research of David Sinclair and his team from Harvard was greeted with international media fanfare. According to their findings, published in Nature, resveratrol was able to increase the lifespan of yeast cells. The results ignited flames of hope for an anti-ageing pill.
According to Sinclair’s findings, resveratrol could activate a gene called sirtuin1 (Sirt1 – the yeast equivalent was Sir2), which is also activated during calorie restriction in various species, including monkeys.
Since then studies in nematode worms, fruit flies, fish, and mice have linked resveratrol to longer lives. Other studies with only resveratrol have reported anti-cancer effects, anti-inflammatory effects, cardiovascular benefits, anti-diabetes potential, energy endurance enhancement, and protection against Alzheimer’s.
“Resveratrol has the biological effects of so many drugs wrapped up in one molecule,” said Bill Sardi, co-founder and president of Resveratrol Partners. Despite the promise of long life, Sardi said that the anti-ageing market has not been the most promising avenue commercially. “Middle-aged men and upwards are more aware of their own mortality, but the general public interest has not been big,” he said.
However, despite the promise, results from human trials are limited.
The funding for such studies should be coming from the US’ National Institutes of health, said Sardi. “NIH should be sponsoring all types of human studies. We’re six years out (from the Nature study) and we haven’t seen anything,” he said.
A review in Molecular Nutrition & Food Research (2009, Vol. 53, pp. 115-128) by scientists from Ludwig-Maximilian-University Munich and the University of Texas appears to agree with these statements. “In spite of these studies, no systematic clinical trial has yet been done with the pure compound. No data are available on its bioavailability in humans. Such studies should be carried out to realize its full potential,” it states.
Studies are reportedly underway. Philipp Siebrecht, global business manager for resVida, DSM’s high purity resveratrol, says several human studies are ongoing with the company’s ingredient. “Results of the first one will be published early in December at the 4th International Conference on Polyphenols and Health in Yorkshire, University of Leeds, England,” said Siebrecht.
“At DSM Nutrtional Products, we also wanted to make sure that the consumption is safe for consumers and conducted an extensive safety package. However, even more critical to watch here is whether the human body can absorb the resveratrol you consume. [We have] studied this in detail in a human trial and at least for resVida we can say that it is bioavailable, so in other words absorbed by the body,” he added.
Dr Sinclair is currently following a drug route for resveratrol. Working Christoph Westphal, a scientific entrepreneur, he founded Sirtris Pharmaceuticals. According to the New York Times, clinical trials are now ongoing for its resveratrol formulation. Sirtris was recently snapped up by GlaxoSmithKline for a tasty $720 million.
There are some concerns over the active doses for the compound. Because there are so few clinical studies conducted on humans related to the ingredient, there is no golden standard for the necessary dosage levels. However, using animal studies as a guideline, minimum levels are thought to be 30mg per person per day.
DSM, for example, recommends that its branded ingredient is used at 30-150mg per day.
Some resveratrol supplements currently on the market include products from Source Naturals and Jarrow Formulas, both of which recommend 30mg resveratrol per day. Another product from Cellular Health Technologies recommends 100mg per day.
However, Sardi cautions against high doses of the compound. He states that resveratrol is a chelator of copper. "Copper is found in red blood cells and collagen, amongst other places," he said. "Resveratrol is not suitable for children or pregnant women. Resveratrol would not be suitable in a food snack bar for children."
However, not everyone is convinced by the hullabaloo surrounding the ingredient. In response to the animal studies which reported remarkable benefits for resveratrol with respect to lifespan, ageing, cancer protection, Bert Schwitters, President of INC, a supplier of oligomeric proanthocyanidins (OPCs), said that the high doses used make such studies “completely irrelevant from a nutritional standpoint”.
“Research into the French Paradox was not done with an eye on resveratrol,” said Schwitters.
“All this news on resveratrol is much inflated. It leads the consumer to think that if they take 30 milligrams of resveratrol they are protected against everything that these test animals are protected against,” said Schwitters. “It doesn’t follow the science.”