Resveratrol

Since resveratrol is found in wine, might its bioavailability be higher after drinking wine, compared to taking it in pill-form? Resveratrol studies have shown that resveratrol’s bioavailability after consuming wine is just as low as or even lower than the results from consuming it in a pill. Researchers from Canada in October 2002 tested the absorption of trans-resveratrol when given orally to 12 healthy people through white wine, grape juice, and vegetable juice. They found that the absorption is broadly equivalent among the three factors. In another research study, researchers from Italy administered red wine to 25 healthy people using three different dietary approaches: fasting, a standard meal, and a meal with high and low amount of lipids (fat-soluble content). The results showed that 30 minutes after the people had consumed the red wine, free trans-resveratrol was found only in some samples collected, and only in trace amounts. A predomination of resveratrol glucuronides was found after longer times. Results also indicated that the type of dietary approach did not cause significant differences in the bioavailability of trans-resveratrol. The researchers raised doubts about the health benefits of dietary resveratrol consumption and suggested that the benefits associated with drinking red wine may be due to the combination of all the antioxidants present in red wine. Other researchers published a study in the Journal of Agricultural and Food Chemistry in February 2004, which revealed that after consumption of grape juice, the bioavailability of resveratrol in its glycoside form was absorbed to a lesser extent than trans-resveratrol.

It has been found that the amount of resveratrol in wine depends on whether the grapes were grown organically and how the wine was made. Resveratrol is produced in the grape plant as a protective response to fungal infection. Therefore, if the plant is treated with pesticides that prevent fungal infection, and with plants grown in dryer climates, less resveratrol is produced. Some wines have no resveratrol content, or very little. The wines that contain the highest level of resveratrol are organic red wines from certain areas of Europe. Red wines have a higher concentration of resveratrol than white wines because in the process of making red wine, the fermentation period, or length of time that the wine is exposed to grape skin, is longer. David Sinclair, co-founder of Sirtris Pharmaceuticals, stated that in order to obtain the same dose of resveratrol used in mice studies that may produce numerous beneficial effects, a person would have to consume 100 to 1,000 bottles of red wine per day. Of course, this method of consuming resveratrol is unwise and unhealthy. Therefore, many have claimed that the best way to get a certain amount of resveratrol daily is to take a pill containing a standardized extract.