by RealSelf Blog
What are Sirtuins?
Sirtuins are a family of proteins found in organisms ranging from bacteria and plants to humans.
According to Los Angeles plastic surgeon John Gross, MD “sirtuins occur naturally within the human body, and when stimulated they can stop the aging clock.” More specifically, sirtuins are defined as a class of seven different naturally occurring enzymes essential to the survival of cells, regulation of metabolic processes and in some cases even as a biological defense mechanism.
What do sirtuins mean for skin?
Basically, sirtuins help prolong the life of cells—so if sirtuins are stimulated then the aging of skin can be prohibited and promote cell longevity.
What stimulates sirtuins?
The original studies on sirtuins were actually related to sirtuin activation as a result of calorie-restriction; according to a New York Timesarticle (6/4/08) the studies, carried out on laboratory rodents, revealed a connection between tissue-preservation and a famine-like diet. In 2003, it was discovered that sirtuins could be activated by some natural compounds--resveratrol being the most touted. Resveratrol is an ingredient found in some red wines—it comes from the skins of red grapes. Resveratrol has also become a popular ingredient in anti-aging skin care.
You may have heard of studies that show animals on calorie-restricted diets live longer, are healthier and show fewer signs of age than those fed normal diets. Though we don't fully understand why, it appears that sirtuins are the key. A growing body of research shows that sirtuins may slow the pace of aging by delaying cell death and protecting cells from DNA damage.
It's unknown whether calorie-restricted diets have the same effects on humans as on fruit flies and monkeys, but it may turn out not to matter-we're learning that you don't need to starve yourself to put sirtuins into action.
A research company called Sirtris demonstrated that resveratrol, an antioxidant found in the skin of red grapes, stimulated expression of sirtuins. Mice placed on high doses of resveratrol improved insulin resistance, prevented weight gain and increased lifespan by 20 percent. When put on a treadmill, the mice were also able to run twice as far and twice as fast than those not given resveratrol.
The New York Times/Well blog
March 11, 2013
New Optimism on Resveratrol
A cloud has long hung over the intriguing thesis that resveratrol, a minor ingredient of red wine, activates cellular proteins known as sirtuins that promote longer life in laboratory worms, flies and mice.
Critics have suggested that there were errors in the original experiments and that resveratrol did not in fact activate sirtuins directly. If so, resveratrol would lose much of its scientific interest because its link to the sirtuin would be unclear. But a new study led by David Sinclair of the Harvard Medical School, who in 2003 was a discoverer of resveratrol’s role in activating sirtuins, found that resveratrol did indeed influence sirtuin directly, though in a more complicated way than previously thought. Resveratrol appears to work by changing the shape of the sirtuin proteins in a cell. Thus activated, the sirtuins do several things, one of which is to switch on a second protein that spurs production of the mitochondria, which provide the cell’s energy. This would explain why mice treated with resveratrol ran twice as far on a treadmill before collapsing from exhaustion as untreated mice.
The exact knowledge of resveratrol’s mode of action, if confirmed, is welcome news for Sirtris, the company Dr. Sinclair helped found to explore whether resveratrol-mimicking drugs could avert the diseases of aging. Resveratrol itself is not ideal as a drug, for technical and patent reasons.
A version of this article appeared in print on 03/12/2013, on page D4 of the NewYork edition with the headline: Nutrition: New Optimism on Resveratrol.
Sources of resveratrol: red grapes, grapeseed and red wines.