Is 1-2 Glasses of Red Wine Such a Good Idea?
You may be excused for not having heard of resveratrol by name but most people, I’m sure will have heard the supposed health benefits of drinking red wine? One of the popular marketing spins from wine companies suggests that one should drink a glass of red wine a day due to the protective, antioxidant benefit of the resveratrol found in red wine. This month, our nutritionist takes a quick look to see if this is actually so.
What is resveratrol and what is it good for?
Resveratrol is a naturally occurring compound in plants that is found in grapes, japanese knotweed, peanuts, cranberry, mulberry, raisins and bilberry among others. The use of resveratrol containing herbs for medicinal purposes is not new. Japanese knotweed, particularly, has a long history in traditional Chinese, Japanese and Ayurvedic medical systems where it has been primarily used as a circulatory tonic. Interestingly enough, with all the hype from the wine industry, you might be thinking that grapes are the highest source of resveratrol. It has been claimed however that Japanese Knotweed is the highest source of resveratrol with 1,000 times that found in grapes.
Research into resveratrol is underway and while still in early stages, has been shown to be particularly promising. In addition to the long acknowledged use of resveratrol for cardiovascular protection, non-human trials have shown resveratrol to be effective in a number of other situations including:
- effective against many forms of tumour both the prevention of initial incidence and ongoing growth and development of many forms of cancer cells including breast, prostate and colon;
- helping to prevent the precursors to type-II diabetes by improving insulin sensitivity allowing better control of blood sugar levels;
- combatting obesity by mobilising existing fat and increasing the rate of fat burning;
- protecting cartilage cells from damage due to inflammation of osteoarthritis and reducing inflammation.
With results like these it is easy to see why the hype around resveratrol. It is important to note, however that these studies are not human trials. Any of the medical studies released so far have been conducted in the test tube or rats.
So, does this mean we should all rush out and follow wine company recommendations of adding one to two glasses of red wine to our diet?
Generally it doesn’t take much to convince Australian’s to race out and enjoy a couple of drinks. It this really going to provide overall health benefits for us though?
First of all, while no guidelines have been established as to what constitutes a therapeutic dose of resveratrol, most studies performed with rats where resveratrol had a therapeutic effect on tumours involved an intake of somewhere between 8mg / kg of (rat) body weight and 25mg / kg of (rat) body weight. Life Extension Magazine, in March 2007, suggested that anti ageing effects in mice were found to occur with an equivalent human intake of 20mg of resveratrol.
Red wine, the highest wine based source of resveratrol contains anywhere between one and a maximum of seven milligrams per litre of wine. To consume even a maintenance dose of resveratrol from red wine would require almost 3 litres of wine each day!
Before you ask, as resveratrol is not stored in the body and breaks down rapidly, a boozy weekend would not allow you to store resveratrol intake for the week.
Secondly, alcohol consumption, even a low intake, is considered a risk factor for almost every condition that resveratrol has been shown to be beneficial for. For example:
- The consumption of one or more alcoholic beverages per day led to a 70% greater risk of colon cancer;
- More than two alcoholic drinks per day has been associated with increased risk of type-II diabetes and insulin resistance;
- Alcohol increases adipose fat storage and decreases fat burning performance by 33%.
What are other ways to obtain resveratrol?
While eating a varied diet with regular use of antioxidant rich berries and grapes will go some of the way to providing resveratrol, it is going to be very hard to obtain the doses used in the literature from diet alone. To prevent people turning purple from excessive grape consumption, a number of resveratrol supplements are now available that provide highly concentrated dosages.