Sources of Resveratrol
Supplements & Drugs
Pills & Powders
Pills and powders containing resveratrol are available in a wide range of styles and qualities. While some are nearly 100% pure trans-resveratrol (the form of resveratrol that activates sirtuins) others may be as little as 10% pure. Further, some companies sell pure resveratrol in a micronized form, which increases its absorption into the body (Micronization is the process of greatly reducing the average particle size of a compound). What is more, some resveratrol pills and powers are sold in combination with additional ingredients such as quercetin, pterostilbene, rice bran, grape seed, grape extract, and red wine extract. Currently, most resveratrol products are derived from polygonum cuspidatum (a.k.a. Japanese knotweed) - a plant native to eastern Asia (but is now found in Europe and North America) that has been used in eastern medicine for centuries. Japanese knotweed is both cultivated in farms and is also found in the wild – generally near water sources. A smaller number of companies derive resveratrol from grapes and/or muscadines (a type of grape native to the southeastern United States known for its high antioxidant levels). Extracting resveratrol from grapes and muscadines is viewed as more costly, however, as resveratrol is found in higher concentrations in Japanese knotweed. In the near future, a major source of pure resveratrol will likely be modified yeast cells which have been ‘reprogrammed’ to produce resveratrol during the fermentation process (instead of carbon dioxide and alcohol). A benefit of this process is that it will provide the market with an extra source of pure resveratrol. This increased supply could be especially important in keeping resveratrol prices down in light of recent skyrocketing demand. After purchasing resveratrol it is important to store it in the proper conditions. Specifically, resveratrol products should not be stored at temperatures greater than 85 degrees Fahrenheit (as high heat can lessen its potency). Further, protect resveratrol from ultraviolet light (e.g. sunlight and some overhead lights), which can also decrease its potency (Note: Some companies sell resveratrol in colored capsules which help shield the resveratrol from ultraviolet light).
Sirtris Pharmaceuticals (a wholly owned subsidiary of GlaxoSmithKline) has developed a formulation of resveratrol it calls SRT501. This formulation is currently in clinical trials and will not be available for 4 or 5 years, pending FDA approval. Sirtris decided not to put SRT501 on the market as a dietary supplement (which it could have) in part because a lower priced supplement may have competed with other higher priced sirtuin activating drugs it is developing. It should be noted that the resveratrol used in SRT501 is micronized in order to improve its absorption into the body. Micronized resveratrol is offered by several companies today.
Foods & Drinks
Wines & Grapes
Perhaps the most well-known food/drink source of resveratrol is wine. Generally, the amount of resveratrol in wine is a function of the type of grape used as well as the methods of production. For instance, wines made from grapes grown in harsh environments (i.e. overly humid, hot, or cool) have higher concentrations of resveratrol than grapes grown in moderate environments and red wines have more resveratrol than white wines. Wines made with grapes grown in harsh conditions generally have more resveratrol than wines made from grapes grown in ideal conditions. The theory behind this is that resveratrol, as a protector from environmental stresses (such as mold, sunburn, diseases, and insects), is activated in harsh environments. Perhaps this is why (according to several studies) muscadine grapes, which are native to the hot and humid southeastern United States, have significantly higher amounts of resveratrol than ordinary table or wine grapes. Further, perhaps this is why studies have indicated that pinot noir grapes grown in cool humid climates have more resveratrol than typical wine grapes. Further, red wines typically have more resveratrol than white wines because red wines are fermented on grape skins, while white wines are not. In short, the resveratrol, which is present in high levels in grape skins, is extracted into the red wine during the fermentation process. Besides choosing the ‘right’ wine, how one drinks wine can affect how much resveratrol is absorbed into the body. Specifically, according to Stephen Taylor, professor of pharmacology at the University of Queensland, "…absorption via the mucous membranes in the mouth can result in up to around 100 times the blood levels, if done slowly rather than simply gulping it down." So, savor your red wine as you drink it.
Other Food Sources
Resveratrol is also present in varying amounts in peanuts, blueberries, cranberries, and dark chocolate.
Note: By mass, dark chocolate has more resveratrol than any other natural food source except for red wine. In fact, according to Harvard scientist Eric Ding, "It has been approximated that eating 50g of dark chocolate per day may reduce one's risk of [cardiovascular disease] by 10.5%."
Note: As mentioned above, heating resveratrol can limit its beneficial effects - so juices that have been pasteurized (e.g. most grape or cranberry juices bought in a supermarket) or berries that have been cooked in an oven (for instance, as part of a pie filling) will have lost at least some of the beneficial effects of resveratrol. As follows, fresh grape, blueberry, or cranberry juices, or grapes, blueberries, and cranberries in their raw form will likely have the most active resveratrol.