Resveratrol is one of several naturally occurring antioxidants found in the skin of grapes and in red wine. Since research on yeast cells in 2003 showed resveratrol increased their lifespan, red wine has gained a reputation as a health food and for supporting a naturally long life. So far definitive results from resveratrol lifespan studies have not progressed beyond worms, fruit flies, fish and mice, with research outcomes on the human ageing effect due later this year (2014).
The value of drinking red wine is supported by the phenomenon known as the ‘French Paradox’, attributing a naturally healthy heart and balanced weight in the French population to the mitigating effects of their regular red wine consumption. While several studies show moderate red wine consumption generally has a positive antioxidant effect, results vary according to vintage and production methods.
What do we know about Resveratrol?
Resveratrol is also present in grape seeds and in a variety of other plants. Its role in the plant kingdom is to protect against environmental stressors, and it is thought to play a similar role in the human body.
Resveratrol’s key protective actions do support the body broadly and research indicates it supports the body through its response to free radical damage. Resveratrol may support healthy immune system, joint health, brain health, cardiovascular health and healthy ageing. It also may support energy and performance during the day. When resveratrol enters the body, it is initially stored in the liver, converted to a bioavailable form and gradually released into the bloodstream over several hours.
While there is plenty of opportunity for in vivo studies into the effects of red wine intake, so far research information on its active ingredient resveratrol is only available from in vitro and animal studies. The conclusions of a human study being conducted by the US National Institute on Aging are awaited, however, more human trials are slow to manifest, mainly due to commercial reasons.
The human study, due to report in September this year is a national research program examining the effects of resveratrol on memory and brain health. Begun in 2012 this resveratrol study is being conducted at 26 U.S. academic institutions that are affiliated with the ‘Alzheimer’s Disease Cooperative Study’.
What are the best dietary sources?
Foods containing high amounts of resveratrol are Japanese knotweed (Polygonum cuspidatum a.k.a. hu zhang), red wine, red grapes, cacao, peanuts, mulberries and blueberries. Organically grown grapes contain higher concentrations of resveratrol because they are required to fight infections naturally. However, the grapes still yield less than red wine, because more resveratrol is released from the skins during the fermenting process of winemaking. Cocoa and dark chocolate (from cacao beans) provide the next highest concentrations while blueberries contain roughly 10% of the grape concentration as part of a diverse mix of antioxidants.
While they may seem attractive options at first glance, consuming large quantities of red wine or chocolate is not the recommended way to increase your resveratrol intake. Each of these foods burdens the liver when consumed in excess, so the best guideline is the old herbalists’ principle: “minimum amounts stimulate, moderate amounts sedate, large amounts poison”. A small quantity consumed regularly is the wise approach.
Manufactured resveratrol supplements are commonly sourced from Japanese knotweed, grape seed and red wine extracts.
What is the recommended daily supplement dosage?
Based on current research, for safe use and optimal benefit doses of 50 to 250 mg a day in divided doses are recommended.
If you are taking blood thinning medications you should check with your health professional before taking Resveratrol. Safety during pregnancy or lactation has not been established at this time.