Athletes who overtrain may put excessive stress on their bodies and become more susceptible to respiratory infections, but the fiber found in nutritional and brewer’s yeast may prevent this immune decline in marathon runners.
Images thanks to ivymushbowl and Ellen Reid.
Moderate exercise improves immunity and decreases illness rates. By far, the most important finding that has emerged from exercise immunology studies during the past two decades is that positive immune changes take place during each bout of moderate physical activity. Over time, this translates to fewer days of sickness with the common cold and other upper respiratory infections. We're talking a 25% to 50% reduction in sick days. Name one drug or supplement that can do that.
And it doesn't take much. Let kids run around for just 6 minutes and you can boost the number of immune cells circulating in their blood stream by more than a third.
At the other end of the life cycle exercise may help prevent age-related immune decline. Sedentary women in their 70s may have a 50% chance of getting an upper respiratory illness during the fall season every year, but walk a half-hour a day and your risk is down to 20%. The runners in the group got it under 10.
Now while regular physical activity improves immune function and lowers upper respiratory infection risk, sustained and intense exertion may have the opposite effect, forming a so-called J-shaped curve relationship. As you go from inactive to active, your infection risk declines, but hardcore athletes that overtrain may actually put excessive stress on their bodies and increase their risk of infection. Then you could lose training days, and your performance could suffer. So what can you do? Well traditional sports medicine doesn't appear to have much to offer, advising athletes to you know, don't pick your nose, avoid sick people, and get a flu shot.
A new study, though, found that one can better maintain one's level of circulating white blood cells after exhaustive exercise consuming a special type of fiber found in baker's, brewer's and nutritional yeast. Brewer's yeast is bitter, but nutritional yeast has a nice cheesy flavor. I use it mostly to sprinkle on popcorn. Anyway, normally 2 hours after cycling-your-brains-out you can experience a dip in circulating monocytes, one of our first lines of defense (white blood cells), but those who had been eating the equivalent of less than 3 quarters of a teaspoon a day of nutritional yeast ended up even better than when they started after strenuous exercise. But does this increase in immune cells translate into fewer illnesses? Well let's try it on some marathon runners.
In the weeks following the Carlsbad Marathon, this is how many runners reported experiencing upper respiratory tract infection symptoms taking a placebo. But if instead they had the equivalent of a daily spoonful of nutritional yeast they cut their rates in half.
And what's even more remarkable is that they felt better. They were asked how they felt on a scale of 1-10. People taking the sugar pills were okay down around 4 or 5, but those taking identical looking capsules of the fiber found in nutritional yeast were up at like 6 or 7. Evidently elite athletes tend to normally experience deterioration in mood state during intense training periods, and before and after a marathon race—but sprinkle on a little spoonful of nutritional yeast and you may feel less tense, less fatigued, less confused—even less angry, and my favorite, significantly more vigor!
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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More on the benefits of exercise in:
Don’t have time? Yes you do! See: Standing Up for Your Health.
What else can we do to preserve our immune function? See:
Nutritional yeast that’s fortified can also be a convenient source of vitamin B12 (Safest Source of B12).
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