Vitamin C is the Devil for endurance athletes… and maybe everyone else too
I’ll never be the fastest, or the strongest, so where I can find advantage I’m generally more than happy to run with it. I thought Vitamin C was an advantage; after all, if you get sick less often, you can train more. And for the most part this strategy worked for as long as I pursued it, but it was recently brought to my attention that it had a major flaw (thanks 182lb pure climber). Vitamin C, and anti-oxidants in general, negate the positive effects of exercise, and are likely to have long term negative health impact as well. Frankly, it shocks me that 1) I didn’t know that already, and 2) it’s quite common to see/hear/read sports nutritionists extolling the virtue of Vitamin C, and anti-oxidants in general, for athletic performance.
Before going any further, full disclosure, I am not qualified in anyway to provide health/nutrition advice to anyone. Fitness, tuning health, and athletic performance are hobbies. Obviously, with an impact beyond how fast, how far, or how long I can ride a bike or run. So I’d love this to be more of a conversation starter, than a my-word-is-gospel kind of thing. While the Missing Remote audience clearly isn’t very chatty, Google analytics tells me that many of you are highly educated, around the same age, and share similar interests :).
With that out of the way, lets take a quick look at a sample of scientific data, much of which is old enough that we should all know this (is it just me?). All but the last one (which is a summary piece linking to a real paper) look to be legit scientific papers, published in real journals, and they all find pretty much the same thing. Vitamin C (and/or anti-oxidants) aren’t great for athletes, or people.
- Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance
- Exercise-induced oxidative stress: cellular mechanisms and impact on muscle force production.
- Antioxidants prevent health-promoting effects of physical exercise in humans
- Antioxidants and Cancer: Backwards? (<-Scary one)
I found this all out about a month ago (thanks again, 182lb pure climber), so still figuring out the impact of taking Vitamin C supplements out of my diet, and clearly even in the long-term completely anecdotal. That said, the results have been incredibly interesting:
- Lower observed resting heart rate: This was completely unexpected, but makes sense. The heart is a muscle, and like other muscles it should adapt to stress (exercise) by getting stronger. A month on, it’s unusual for me not to see a number that is 5-8 BPM lower than it was in a similar state of rest (e.g. watching TV, waking up, sitting for any length of time, etc) a month ago. For reference, I haven’t seen any real change in resting heart rate in years, so this seems to me the most quantifiable and interesting output.
- Weight gain: Road cycling is my primary activity, so I’m not super thrilled about this, but gains appear to be mostly in muscle (I have a scale that guesses body makeup). So as long as the W/kg is trending in the right direction, I shouldn’t complain too loudly.
- Increased muscle performance (maybe): I haven’t taken an FTP test recently, so I can’t put hard numbers behind this (and even if I had, nearly impossible to isolate), but I have certainly noticed an improvement here. Both in peak, and sustainable output over time for longer efforts on the bike (measured using a power meter) as well as an increase in repetitions for body weight exercises (e.g. pull/push ups). It’s possible that this is straight placebo (I feel like I should be stronger, so I perform better). It’s also possible that an increase in protein intake a few weeks before removing Vitamin C is muddling the results here (as well as #2). But, on that point, I was pretty close to 1g/lb beforehand, so I added the 30g more as insurance to hit that target, than because I thought it was a deficiency in my diet.
- Increased muscle definition: Could be a big decline in body fat %, but the scale doesn’t indicate that. And if it was, #2 would be have to be slanted toward muscle gain. So win-win.
Again, I’m not a nutritionist, medical doctor, sports scientist, or anything beyond someone who is very interested in maximizing small advantages to produce better results. If this is a topic of expertise, or interest, let me know your thoughts either here in the comments or, as this is obviously quite personal, via email (or whatever).