Last week I spent most of the week with a mild head cold. Nothing crazy, but enough to motivate me to review my old immunology notes yet again to relearn what I already know (it’s always fun picturing the T-cells destroying the bad stuff). Times like these also motivate me to relearn other things, like how nothing gets rid of a cold other than some basics including: sufficient rest, fluids, stress management and a good diet.
Sometimes when I’m sick, I’ll also scan the literature for new research on the common cold. Usually it’s more of the same: sleep deprivation triggers a depression in immune function, more research is needed to show if supplement X helps, excessive exercise causes a depression in immune function while light exercise may help, and so on.
However, in today’s search, I came across something new that may help us cope with the common cold. The only downside is that this new information applies to a small subset of the population. It fact it’s so specific, it’s almost not worth mentioning and learning…other than the fact that the specific subset I’m referring to is exactly who we are: athletes to train vigorously in cold weather!
What does the science say?
In general, it’s has been proven time and time again that popping vitamins does not help to speed up the recovery associated with the common cold if you are already sick. Long-term supplementation also does not help to prevent the common cold. There is some research suggesting that long term supplementation may reduce the duration of the cold, but that always sounded like a lot of effort and money for a marginal improvement on something that rarely happens.
So I had long given up on vitamin C. Maintain a healthy diet rich and fruits and vegetables, and that was all I needed in my mind (if I achieve said goal).
That was until I came across this article. In their review, they mentioned three studies that showed specific groups who responded to vitamin C in specific and acute situations. You can see a summary of the results here:
The first study looked at Swiss children who participated in a ski camp in the Alps. Throughout the study, 139 subjects received 1g/day of vitamin C, while 140 subjects received a placebo. Of the 139 vitamin C subjects, 17 ended up getting sick while 31 got sick in the placebo group. So, without the supplementation, these kids were almost twice as likely to get sick. It’s important to note that this type of trend is not seen in subjects who are not extremely active or spending significant time in cold environments.
The second study had completely different subjects and conditions, but we saw a similar relationship. This one looked at subjects who were conducting a military exercise outdoors during the winter in Northern Canada. Once again there was a vitamin C group where subjects were given 1g/day (11% of the subjects got sick) and a placebo group (25% of the subjects got sick). As with the Swiss Alps study, this one suggested that vitamin C supplementation with 1g/day will halve (in this case slightly more than) your chances of contracting and upper respiratory infection.
The third study in this chart does not take place in the cold, but does apply directly to us. These subjects were followed after a 90K ultra race in South Africa. One group was given 0.6g of vitamin C/day, and other group a placebo. Once again, the placebo group was about twice as likely to get sick as 68% ended up contracting upper respiratory infections, while only 33% got infected in the vitamin C group.
So, according to studies like the above, contrary to most situations, individuals who exercise vigorously and spend extensive amounts of time in the cold seem to really benefit from the supplementation of vitamin C in close proximity to that specific source of stress.
This is quite useful because it does not require a long-term vitamin C load to see benefits as it does in other situations. Also, the benefit is a little more concrete than what we see in the general population. It’s not a matter of having a chance at taking 24 hours off the recovery time (who really knows or cares if that actually happens once you are sick?), but you are specifically about 2x more likely to get sick if you do not supplement.
While these three studies are a little dated, the information they provide still has not been refuted despite the growing body of evidence against vitamin C supplementation. The Cochrane Library is the gold standard for medical research reviews, and in their most recent review of vitamin C supplementation (2007) to prevent upper respiratory tract infections they still suggest it is generally not recommended unless you are exercising vigorously and in the cold.
So should the general public supplement with vitamin on a regular basis? No.
Should the general public start taking vitamin C once they are already sick? No.
However, for those who exercise vigorously and spend extended periods of time in the cold (did anybody do a long run this past Saturday?), taking 0.6-1g/day while you recover from that source of stress may not be a bad idea.
I think it’s also important to note that while these studies were completed using supplements, I still believe it’s always best to ingest what you need through dietary sources.
There is a huge body of evidence across all walks of health that strongly suggest that even though substance “x” is the active ingredient in a food that helps us, isolating that substance “x” and then consuming it does not result in the same type of benefit. I think this research should, at the very least, motivate you maintain a complete and healthy diet loaded with fruits and vegetables through the winter months and your heavy training. Then, after an extremely hard effort (like a max effort marathon in the cold), considering the short-term use of vitamin C supplementation to recover is warranted.
Finally, just to provide you with an incentive to not overuse vitamin C supplements, I want to remind runners that excessive use of antioxidants (including vitamin C) reduces the gains that we see from a given workout. In other words, if you always supplement with antioxidants, you will not reap the full benefit of the workout you pushed so hard to achieve. Researchers believe that anti-oxidant supplementation dampens the inflammation and adaptation stimulating signals our bodies exhibit and benefit from after a hard effort. You can read my full article on this subject here.
It looks like we have some cold days ahead, and the spring marathon season is just around the corner. I hope this article helps you to strategically use vitamin C in specific situations to help you stay healthy!