What comes to mind when you think about resveratrol? Some of us may think of antioxidants, chemical pathways, and chronic disease, but chances are that most of us will think of a big glass of red wine. And when writing from Napa, surrounded by fields of grapevines, what better phytonutrient to study? Resveratrol has been in the spotlight recently; sales of resveratrol supplements in the United States alone come out to approximately $30 million per year. Despite its media popularity, however, research surrounding the compound is controversial.
We know that resveratrol is found in wine, but where does the chemical actually come from? Grapevines and other plants produce resveratrol in response to environmental stressors such as strong sunlight, drought, or invasion by a pathogen. It is most concentrated in the skin of the grape, which is why red wine has much more resveratrol than white. Other foods that are high in resveratrol include blueberries, cranberries, and peanuts. Most of the laboratory studies focusing on resveratrol have been done in vitro (with cells outside of the organism) or in animals, which means that we have to be careful about extrapolating the findings to humans. However, the observations that have been made thus far about this phytonutrient show exciting potential.
Resveratrol was first discovered in Japan in the 1940’s. It has been long used in traditional Chinese medicine to help with medical issues from fungal infections and gastrointestinal issues to cardiovascular disease and diabetes. It began to gain serious media attention in the 1990’s, when researchers suggested that it might be responsible for the French paradox. Studies have shown that resveratrol has the ability to help protect our hearts by lowering levels of bad cholesterol in the blood and by fighting free radicals as an antioxidant. This free radical activity may also make it useful in the fight against diabetes and cancer.
Resveratrol may slow aging by mimicking the effects of calorie restriction. There has been evidence that a moderate restriction in food intake can improve metabolic efficiency and extend lifespan. Resveratrol is a pleiotropic compound, which means that it can stimulate genes to have different effects. Studies have found that resveratrol may influence certain genes in the same way that calorie restriction does to positively impact metabolism. Some of these genes may also be important for the protection of brain cells, which has spurred interest in resveratrol as a possible contributor to treatment for conditions such as Alzheimer’s disease.
In nutrition and medicine, it’s easy to get excited about the research (and to take any excuse to drink more wine). However, it’s important to step back and think about it in practical terms. As mentioned before, most of the studies done with resveratrol have been done outside of the human body. This means that we have a pretty limited understanding of what exactly happens when humans ingest resveratrol in its whole form. The activity of resveratrol may be limited by poor absorption, or by differences in the type and numbers of bacteria that live inside our digestive tracts. We also have different metabolic rates than other mammals, meaning that the amount of resveratrol that has a certain effect on mice may have a very different impact on humans. We need to consider dosing. The resveratrol content of red wine can range from 0.0 mg/L-12.5 mg/L. That means that on average, you’re only going to get around 1 mg of resveratrol in a standard 5 oz glass. In the lab, scientists usually need to give their test animals around 450 mg of resveratrol to see a clinical effect. To put that in perspective, you would need to drink around 36 liters or 450 glasses of wine at a time to really see the health benefits.
So what does this all mean? When it comes to resveratrol, the key word is potential. We’re at an exciting point where we’re just starting to look at the phytonutrient’s effects in humans. Stay with me as I explore some of the research in more detail.
References
Anekonda, Thimmappa S. “Resveratrol—a boon for treating Alzheimer’s disease?” Brain research reviews 52.2 (2006): 316-326.
Calamini, Barbara, et al. “Pleiotropic mechanisms facilitated by resveratrol and its metabolites.” Biochemical Journal 429.2 (2010): 273-282.
Chachay, Veronique S., et al. “Resveratrol–pills to replace a healthy diet?” British journal of clinical pharmacology 72.1 (2011): 27-38.
Das, Dipak K., Subhendu Mukherjee, and Diptarka Ray. “Erratum to: resveratrol and red wine, healthy heart and longevity.” Heart failure reviews 16.4 (2011): 425-435.
Frémont, Lucie. “Biological effects of resveratrol.” Life sciences 66.8 (2000): 663-673.
Marchal, Julia, Fabien Pifferi, and Fabienne Aujard. “Resveratrol in mammals: effects on aging biomarkers, age‐related diseases, and life span.” Annals of the New York Academy of Sciences 1290.1 (2013): 67-73.
Subramanian, Lalita, et al. “Resveratrol: challenges in translation to the clinic—a critical discussion.” Clinical Cancer Research 16.24 (2010): 5942-5948.
Timmers, Silvie, et al. “Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans.” Cell metabolism 14.5 (2011): 612-622.
“Topics of Interest: Resveratrol.” National Institute on Aging. Accessed 27 August 2016.
Vang, Ole. “What is new for resveratrol? Is a new set of recommendations necessary?.” Annals of the New York Academy of Sciences 1290.1 (2013): 1-11.
Walle, Thomas. “Bioavailability of resveratrol.” Annals of the New York Academy of Sciences 1215.1 (2011): 9-15.
Yoshino, Jun, et al. “Resveratrol supplementation does not improve metabolic function in nonobese women with normal glucose tolerance.” Cell metabolism 16.5 (2012): 658-664.