Which Comes First, Cardio or Weights_ - Alex Hutchinson [88]
Antioxidants—vitamins C and E plus molecules ranging from beta carotene to currently fashionable resveratrol—attack and neutralize the “free radicals” associated with aging and disease. Exercise stimulates the production of free radicals, which is why athletes are often advised to take extra antioxidant supplements. But exercise itself is also an antioxidant. During exercise, the body gradually learns to produce more and more of its own antioxidants in response to the spike of free radicals generated by working out. One theory now gaining support is that taking extra antioxidants means that the body never gets the opportunity to adapt on its own.
In 2009, Michael Ristow and his colleagues at the University of Jena, in Germany, published a study in the Proceedings of the National Academy of Sciences examining how a four-week exercise program affected insulin sensitivity—one of the most significant health benefits conferred by physical activity. Half of the 40 volunteers were given a placebo and saw significant improvements in insulin sensitivity; the other half took 1,000 mg of vitamin C and 400 IU of vitamin E each day and saw no change despite the exercise regime. To Ristow, this suggests that antioxidants are unequivocally bad, even though the research in favor of eating fruit and vegetables is unimpeachable. “This insinuates that fruit and vegetables are healthy despite their content in antioxidants,” he explains, “[so] other compounds in fruit and vegetables are responsible for their health-promoting effects.”
The idea that antioxidants can stave off some of the muscle damage and soreness caused by free radicals after heavy exercise has also taken a hit. In 2009, researchers studying the Portuguese national kayak team found hints that, compared with a placebo, a cocktail of antioxidants actually delayed muscle recovery after training. Victor Hugo Teixeira of the University of Porto, the study’s lead author, speculates that free radicals may serve as a natural brake to stop you from pushing too hard. Taking antioxidant pills could override that brake, allowing your muscles to work a little harder and sustain greater damage. If that’s true, athletes might gain an edge from taking antioxidants right before a competition but would suffer from impaired recovery if they took them on a regular basis.
Even if antioxidants did ruin your workout, many people would gladly take that risk if it helped them avoid the flu. It’s well established that antioxidants can help boost immune function in people who have undergone truly extreme physical exertion, like running an ultra-marathon, Cheung says. But it’s less clear that the same benefits accrue in everyday life. In a study published last year, Cheung had volunteers cycle at moderate intensity for two hours—hardly slacking—and tested whether their immune function was helped by 1,500 mg of vitamin C a day for two weeks afterwards. The results were equivocal: if there was any effect, it was weak.
Cheung’s advice is to ensure you’re getting enough vitamin C from your diet—and if not, to change your diet before resorting to supplementation. In a field where the science is still hotly contested, this seems like wise counsel. Someday, perhaps, we’ll know exactly which molecules make fruit and vegetables so good for us—but until then, as long as you’re eating lots of them, you don’t have to worry about which ones.
Should I be taking probiotics?
Over the last few years, grocery store shelves have been taken over by “helpful” bacteria. Particularly in the dairy section, foods now trumpet the presence of live cultures and the health benefits they offer. The general term probiotics refers to live micro-organisms that interact with the existing bacteria in your gut to produce a positive effect on your health. Some of the most common examples are bacteria that feed on lactose and are used in the fermentation process to produce yogurts and cheeses.