Trans-resveratrol is one form of a compound produced by some plants to combat fungal infection. When ingested, trans-resveratrol might provide health benefits, ranging from protection against disease to antiaging properties. Research into the potential benefits of trans-resveratrol is ongoing, but few human studies have been performed so far.
The polyphenoic compound resveratrol belongs to the group of chemical compounds called stilbenes. Resveratrol comes in two forms, cis and trans, both of which may be attached to a glucose molecule. When attached to glucose, resveratrol is called a glucoside. Both the cis and trans forms can be found in nature, but they may not have the same biological properties when ingested. Most research on the potentially beneficial effects of resveratrol have been performed on the trans isomer.
Much of the evidence for the activity of trans-resveratrol is from laboratory studies, not human clinical trials. In the lab, trans-resveratrol acts as a powerful antioxidant, binds to estrogen receptors, inhibits tumor activity and affects cellular enzymes. Most research done on trans-resveratrol uses doses much higher than the amounts found in natural sources. Animal studies have linked trans-resveratrol to heart protective effects, anticancer activity and antiaging properties. Some studies link wine consumption to decreased mortality and a lower risk of heart disease, such as a 2004 study published in the "American Journal of Epidemiology." Since wine, particularly red wine, is a major source of trans-resveratrol, this may be a mechanism behind wine's protective effects. However, more studies are required to establish a definitive link.
Trans-resveratrol metabolism occurs rapidly once it is ingested, which means that it doesn't spend much time in the body before being altered and eliminated. The levels of trans-resveratrol and its metabolites are at their highest about 30 minutes after consumption, according to the Linus Pauling Institute. Few studies have been done on the metabolites themselves, so it is not known whether they share the same biological activity as trans-resveratrol or if they become inert after being altered by the body.
The main dietary source of trans-resveratrol is red wine, but other forms of wine and other grape products also contain this compound. Because resveratrol is concentrated in the skins of grapes, the amount of time a wine or juice spends in contact with the skins can affect the resveratrol content. Red wines and dark grape juices have more trans-resveratrol than white wine or juice. Other berries, including bilberries, cranberries and blueberries, also contain trans-resveratrol. Peanuts and peanut butter are another food source of resveratrol.