The truth about antioxidants

They're given credit for everything from beefing up your workouts to halting ageing, but how much do antioxidants really do? We separate the science from the hype
By Flannery Dean

Antioxidants - including vitamins A, C, E, and beta-carotene - are potent free-radical fighters, and health food stores are stocked with antioxidant-rich multivitamins and supplements. But how much of the news about these disease-defying vitamins is fact, and how much is fiction?

We checked up on four claims:

Antioxidants are powerful disease fighters.
True. Antioxidants, which are naturally occurring chemical compounds in food (or created by the body), help keep us healthy by combating cell damage. They’re thought to play a significant role in the prevention of a number of diseases, including cancer, heart disease and even Alzheimer’s.

You need a daily vitamin - packed with antioxidants - to maintain overall health.
False. Dr. Venket Rao, a professor in the Department of Nutritional Sciences at the University of Toronto, says if you follow Health Canada’s guidelines for a balanced diet, you’ll get all the essential nutrients you need. But that doesn’t mean that there isn’t a place for supplements in your life, or your medicine cabinet. According to Dr. Rao, during a high-stress period in your life it may be wise to take a multivitamin. "Under these conditions our need for nutrients may exceed the normal recommended levels."

Supplements are the best way to get antioxidants and other essential nutrients.
False. “Our body recognizes and processes all nutrients, either from foods or from supplements, in a similar manner,” says Dr. Rao. Food sources are safer though, mainly because we generally know what we’re ingesting when we eat an apple, whereas we don’t know all of the chemical components that may be present in a commercial supplement. For example, some companies may be sourcing their raw ingredients from China, which may lead to contamination. An American study found that several brands did not contain the vitamin dosage advertised on the label. Even more serious: one brand contained an unhealthy amount of lead. Dr. Rao advises you do some research about your brand of choice. “Make sure of the level of the nutrient, its chemical form and other components that may be present in the supplements.”

Antioxidants negatively impact workouts.
It’s complicated. High-performance athletes (think Lance Armstrong or Cindy Klassen) are often told to take antioxidant supplements to offset the burden of putting the body through intense workouts. (Exercise actually increases free radical production, though over time it also boosts the body’s antioxidant response.) One German study concluded that supplements - vitamins C, and E, specifically - blocked one of the main benefits of exercise: increased insulin sensitivity, or the ability of the body to process glucose for energy. Another study found that supplements taken during intense training actually impaired muscle recovery. Reaction to both studies is mixed. Dr. Rao feels the German study defined “workout” too broadly. “Untrained subjects doing 85 minutes of workout daily, five times a day is not a normal workout schedule,” he says. “Physical activity is something that should be built up gradually allowing the body to adjust to various metabolic, hormonal and free-radical stresses.” In his opinion, taking the recommended level of nutrients daily, via food or supplements, can be beneficial when you’re working out at a safe and steady pace.


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