Eat Well to Stay Well

How the Right Foods Can Keep Your Immune System in Top Shape

How many times have you gotten yourself into terrific shape, only to come down with a cold the week before your big race? Or perhaps you make it to the finish line, but you can’t run a step for the next 10 days as you recover from strep throat or flu. What’s going on? For the most part, running seems to confer a protective effect against colds and other upper respiratory tract infections. In fact, most runners report suffering from fewer colds when compared to sedentary folks.

You’re not alone, though, if you feel particularly vulnerable to illness during periods of heavy training or immediately before or after an important race. Many elite athletes have been undone by colds and other viruses. Alberto Salazar reportedly caught 12 colds in 12 months while training for the 1984 Olympic Marathon. Competing with an obviously overstressed immune system, he finished 15th after entering the race as one of the favorites. In hopes of preventing a run-in with the sniffles (or worse), many runners down large doses of nutrients commonly believed to strengthen the immune system, such as vitamin C, zinc and glutamine. Avoiding sick people and large crowds is another strategy. You may, however, have overlooked one of the simplest, but most effective means of bolstering your immune system. A growing body of evidence suggests that paying attention to what you eat and when you eat it can have dramatic effects on your ability to thwart the common cold and other infections.

Running from Viruses

The study of how exercise effects the body’s immune system dates back to the turn of the century, but it wasn’t until the early 1990s that researchers really began to look at the immune systems of athletes. They found that despite the supposed protective effect of exercise, the immune systems of athletes are surprisingly similar to those of non-athletes. The only notable exception is that very fit people possess natural killer cells that are more active, which could give these individuals a greater ability to detect and destroy threats such as viruses and even cancer cells.

It’s after exercise—particularly prolonged, intense bouts—that many components of the immune system exhibit adverse changes. "There is an ‘open window’ or downturn of the immune system which lasts several hours to a few days," contends David Nieman, D.P.H., professor of health and exercise science at Appalachian State University in Boone, NC, and one of the country’s leading exercise immunologists. Depending on other factors, such as poor eating habits, inadequate sleep and mental stress, a particularly intense or long running effort may be the final blow to an overtaxed immune system. Viruses and bacteria can gain a foothold at this time, disrupting your training and racing plans.