One recent study found that antioxidant compounds caused fertility problems in mice. Though popular among athletes, antioxidants have not been shown to improve performance or speed recovery. On the contrary, supplementing with antioxidants may blunt the beneficial effects of working out. Also, while some dietary antioxidants may have a role in cancer prevention, excessive doses of some vitamins can aggravate illness or even cause it, researchers say.
“People should be aware that there is little to no data supporting the use of antioxidants to protect against disease,” said cardiologist Toren Finkel, chief of the Center for Molecular Medicine at the National Heart, Lung, and Blood Institute.
Yet “antioxidants” remains one of the hottest buzzwords in the health and wellness industry.
In the U.S., sales of top antioxidant supplements hit $5 billion last year, up 2.3% over 2009, according to Nutrition Business Journal.
A natural by-product of eating, drinking and breathing, free radicals are an unavoidable hazard of living.
“Oxygen oxidizes our food to produce energy, and the oxygen is reduced, mostly to water,” said biochemist Barry Halliwell, a pioneering researcher in free radicals and disease. But some oxygen winds up as free radicals, or unstable molecules that are missing an electron.
Desperate to regain its balance, a free radical will steal an electron from the nearest substance, whether it’s cellular DNA, protein or fat. The theft alters the structure of the nearby victim, creating another unstable compound and triggering a chain reaction.
In response, our bodies naturally produce antioxidants that, like loyal bodyguards, defuse free radicals by donating electrons while staying in balance themselves -- a system people can strengthen through regular exercise.
However, aging and exposure to environmental stressors from sunburn to pollution make it harder to keep up with antioxidant production, said Amy Howell, an associate research scientist at the Marucci Center for Blueberry Cranberry Research at Rutgers University.
For example, X-rays create oxidative stress because “radiation splits the water to make free radicals,” said Halliwell, a deputy president of the National University of Singapore. And “cigarette smoke is already full of free radicals that attack the lungs and other parts of the body.”
Researchers have known for decades that diseases including heart disease, cancer, stroke and neurodegenerative disorders are linked to damage caused by free radicals. They also found that people who eat a diet rich in fruits and vegetables have lower rates of disease.
As a result, they hypothesized that taking antioxidants as supplements or fortified foods could decrease oxidative damage. However, when antioxidant compounds were tested, the results were largely disappointing.
Beta carotene supplements did not just fail to protect people against cancer; they increased the risk of lung cancer in smokers. Trials looking at cardiovascular disease, other cancers and strokes have been mixed, but most haven’t found the hoped-for benefits. When Ironman-distance triathletes supplemented with vitamin E for two months, it actually exacerbated oxidative stress and inflammation.
Meanwhile, free radicals aren’t necessarily always “bad.” The oxidant hydrogen peroxide, for example, can help open blood vessels; removing it with antioxidant therapy can impair the body’s ability to get oxygen to muscles.
There is also some evidence that what does not kill you can make you stronger: A little short-term free radical damage may actually activate pathways in the body that are protective in the long run, Finkel said.
From the October 11, 2011, Prepared Foods' Daily News.