Resveratrol – Not Enough in Red Wine for Effect

Wine, Fruit Have Too Little Resveratrol to Defeat Aging Symptoms

Sep 21, 2009

Resveratrol from red wine grapes has been hailed as a miracle anti-aging factor. A food scientist explains that fruit or wine can't provide enough without supplements.

Resveratrol, a polyphenol antioxidant famously found in red wine, and believed to be the factor behind the ‘French paradox’, is also a component of pomegranates, blueberries, olive leaf and other ‘wonder foods’ believed to reduce oxidative stress from free radicals and so prevent the symptoms of aging.

The problem, according to Australian nutritional scientist Christine Houghton, is that the amount of the substance the body can obtain from fruit is a tiny percentage of what the fruit contains, so that despite the benefits of eating plenty of fruit, getting enough resveratrol isn’t one of them.

Ms Houghton, who has been a nutritionist for 30 years, has been researching nutritional medicine and the development of nutraceuticals to supplement people’s diets.

She recently wrote a two-part article comparing the bio-availability of resveratrol with a commercial supplement, GliSODin, for a Clinicians in Nutritional Medicine conference, and answered Suite101.com’s questions.

Antioxidants in Fruit Not Readily Available to the Body

“All polyphenols are poorly bioavailable,” she said, with only 8 per cent or less of a fruit’s polyphenols being taken up by the body.

“They also depend on healthy gut microflora for their conversion to their bioactive forms. Clearly, this poses significant barriers in all individuals, further compounded in those with poor microflora status.”

Ms Houghton, who is working towards a doctorate, explained that “many of the studies which demonstrate impressive effects of polyphenols are cell culture in vitro studies (using cell cultures in test-tubes or Petri dishes), and not human clinical or even animal intervention trials.”

She added that “the doses used in cell culture are often so high that they are not practically achievable in a clinical environment.”

An Australian study into the benefits of resveratrol was dismissed by Ms Houghton, as the substance was trialed only on mice.

“The highly-promoted study by Australian researcher David Sinclair shows that resveratrol, when administered to mice (not humans) retards the aging process.

“More so, there was no longevity benefit to ‘middle-aged’ mice; increased lifespan was only seen when the mice were started on the supplement at birth.

“The research tells us nothing about whether this effect occurs in humans at manageable doses,” she said.

Antioxidants Important in Protecting Against Free Radicals

Ms Houghton said she did not question the value of plant-based antioxidants, and the importance of eating a wide range of fruits and vegetables.

“Without a doubt, polyphenols are beneficial in human health and are the premise on which the Mediterranean Diet and the ‘French paradox’ are based depends on their presence in the diet.”

(The ‘French paradox’ is that French people regularly drink wine with their meals, yet, although their diet is comparatively rich in saturated fats, they have a lower rate of cardiovascular disease than Americans and Australians.)

However, she said, new studies on the ‘French paradox’ show that their effect “is primarily due to inhibiting the oxidation of food with which the polyphenols come in contact directly in the gut. Their systemic effects are comparatively much more limited,” she concluded.

Fruit and Vegs in Diet Vital, But Need Supplementing

“I’m not suggesting that people don’t need to eat plenty of fruit and vegetables in their diet,” she said.

“These foods are very important for getting enough vitamins, minerals and fibre. Sadly, many people don’t eat the recommended 5 cups of vegetables and two cups of fruit a day.”

However, even those who do manage to consume that large amount of fresh plant material won’t be getting all the antioxidants the body needs to prevent free radical damage to its cells.

The solution, she suggested, was to eat a healthy diet, and supplement it with commercially available antioxidant products that are hundreds of times more effective than resveratrol.

One such supplement is GliSODin, a nutraceutical developed from melons, which Ms Houghton said “switches on the genes which allow the body to make its own antioxidant enzymes.”

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