To prepare for action, Superman tears off his business suit, revealing the unmistakeable emblem and on his chest, and he is in full spandex gear and cape and ready to fight supervillains. Way back when, Popeye would consume large amounts of spinach to gain strength, and the Tarahumara super-runners described by Christopher McDougall in his 2009 book Born to Run eat iskiate made of nutrient-packed chia seeds to help them during day-long sprints through mountainous terrain.
On our runs, we may want to improve our performance or at least protect ourselves from injury, so we too have supergear and superfood. This is especially important in the winter, when the cold air and hard ground are tough on our bodies. So we whip out the Under Armour -- perhaps even a facemask to emulate Batman and for dramatic effect -- and we may prep in advance by loading up on antioxidant vitamins to help reduce muscle and respiratory damage. (After certain December events and e-mails, I'm inclined to think that some of us prefer to snap on a pair of red speedos and throw back a beer, but this really may not be the best idea for every day.)
Vitamins like C and E may neutralize harmful reactive oxygen species whose production rises during times of increased energy use, such as running, and potentially mitigate their effects on muscle. Vitamin E in particular has been shown to affect immune cells and reduced the number of respiratory infections experienced by elderly study participants at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Because cold weather running poses risks to muscle and to the respiratory tract, these antioxidant vitamins seem like a logical choice.
However if you browsed the New York Times or Boston Globe last May, you may have seen the headline "Vitamins Found to Curb Exercise Benefits." When you pick up your copy of O, The Oprah Magazine, this month -- I know you all read it -- you will see a similar article. So what's the deal here?
The argument is that reactive oxygen species, while they have adverse effects, are actually part of the whole system of biofeedback that enables the body to notify its natural defense mechanisms of the need to respond to stress. Large quantities of antioxidants, therefore, may undermine this response. The proposal is based on results of a trial conducted at the University of Jena in Germany in collaboration with Joslin Diabetes Center at Harvard University (Ristow et al. 2009), where 39 young men performed 85 minutes of exercise five days per week for four weeks while receiving vitamin C and E supplementation or a placebo. The group receiving vitamins showed very little activation of the natural defense response that kicked in after exercise in the group receiving placebo, creating -- as one might imagine -- a great deal of controversy about the implications of taking these vitamins, especially for athletes. If we take vitamins, are we actually making our bodies weaker and reliant on an outside source of protection and repair?
Hmmm. This sensation was caused by one particular study, which -- like all well-designed studies -- has both its credibility and its flaws. One criticism is that not all antioxidants may have the same effects. In addition, that the amounts of vitamins given were high -- more than ten times the daily amount recommended by the Institute of Medicine -- and would not typically be contained in food or even a multivitamin, and smaller amounts may not have the same effects. I would also add that the principal purpose of the study was actually to investigate the effects of exercise plus vitamins on insulin sensitivity as it relates to diabetes, and looking at natural defense response to reactive oxygen species was a secondary goal. While researchers did compare the expression of two genes (superoxide dismutase and glutathione peroxidase) implicated in this response, I wonder whether there would have been more analyses had this been the primary goal. Finally, this study evaluated the long-term effects (before exercise regime versus one week after conclusion of exercise regime), so results may also be different if natural defenses were measured directly after exercise.
The conclusion? There really isn't a clear message like "eat spinach" from Popeye. (Did that really work for kids? Somehow I doubt it ...) Should you eat vitamin C-rich kiwi and grapefruit and vitamin E-rich almonds? Yes. Fortified cereal and energy bars? Sure. Multivitamins? Probably fine. Vitamin C powder and vitamin E capsules? This is where you get into the high quantities used in this study and onto shaky ground. As always, more research is necessary but basically, we need to realize that it shouldn't be our superhero superfood. Instead you might learn from Popeye and the Tarahumara and go for simple, whole foods. These contain multitudes of compounds with many potential benefits, so they're a good bet even if one theory doesn't quite pan out. Happy New Year, and enjoy your run.
~ marina komarovsky
Illustration by Inna Komarovsky
