Resveratrol

The potential that resveratrol may have to bring about weight loss and enhance athletic performance has also been researched. Scientists in the USA, France, and Finland published their collaborative research in the journal Cell in November 2006. In their study, mice were fed resveratrol for 15 weeks and examined for their aerobic capacity. It was found that the mice significantly increased their treadmill endurance, running for longer times and having higher consumption of oxygen in their muscle fibers. Resveratrol significantly increased the number of mitochondria in the mice’s cells, therefore they were able to burn more calories and avoid weight gain. Mitochondria convert energy into forms that are usable by the cell. Furthermore, resveratrol treatment protected mice against diet-induced-obesity and insulin resistance. These effects of resveratrol are due to the activation of the SIRT1 gene as a key regulator of energy and metabolic homeostasis.

Given all the positive reports that testify to resveratrol benefits for a wide range of health issues and diseases, are there any negative effects known to be associated with it? There are no studies so far that indicate resveratrol causes adverse effects in humans. However, its safety has not been well evaluated and clinical trials on humans are few. A study in 2007 showed that healthy human volunteers who took oral resveratrol in single doses ranging from 0.5 to 5g did not experience serious adverse effects. At least two studies have been carried out on rats, which were given trans-resveratrol in oral doses of up to 300 mg/kg of body weight. In these studies no adverse resveratrol side effects were observed.

Resveratrol’s chemical structure is similar to that of a phytoestrogen, and has the ability to cause estrogenic or/and antiestrogenic effects. One study has shown that resveratrol activates the expression of estrogen-responsive reporter genes, and fully activates expression of endogenous estrogen-related genes, inducing the growth of breast cancer cells. Another study has shown that resveratrol acts as an estrogen agonist under some conditions and as an estrogen antagonist under other conditions. It is notable that other studies have indicated that resveratrol can help prevent and treat breast cancer.

Due to its estrogenic nature, resveratrol is not advised for use by women with a history of estrogen-sensitive cancers, such as breast, ovarian, and uterine cancers, as well as those who are pregnant or intending to become pregnant. The safety of resveratrol during pregnancy and lactation has not been established and resveratrol may interfere with oral contraceptives. Furthermore, until more studies are done, resveratrol should not be taken by children under 18.