[MikeMartial]

Vitamin C for preventing and treating the common cold.
Douglas R, Hemilä H, Chalker E, Treacy B.

BACKGROUND: The role of vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for 60 years, but is widely sold and used as both a preventive and therapeutic agent. OBJECTIVES: To discover whether oral doses of 0.2 g or more daily of vitamin C reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of symptoms. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2006); MEDLINE (1966 to December 2006); and EMBASE (1990 to December 2006). SELECTION CRITERIA: Papers were excluded if a dose less than 0.2 g per day of vitamin C was used, or if there was no placebo comparison. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed trial quality. 'Incidence' of colds during prophylaxis was assessed as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean days of illness of cold episodes. MAIN RESULTS: Thirty trial comparisons involving 11,350 study participants contributed to the ****-analysis on the relative risk (RR) of developing a cold whilst taking prophylactic vitamin C. The pooled RR was 0.96 (95% confidence intervals (CI) 0.92 to 1.00). A subgroup of six trials involving a total of 642 marathon runners, skiers, and soldiers on sub-arctic exercises reported a pooled RR of 0.50 (95% CI 0.38 to 0.66).Thirty comparisons involving 9676 respiratory episodes contributed to a ****-analysis on common cold duration during prophylaxis. A consistent benefit was observed, representing a reduction in cold duration of 8% (95% CI 3% to 13%) for adults and 13.6% (95% CI 5% to 22%) for children.Seven trial comparisons involving 3294 respiratory episodes contributed to the ****-analysis of cold duration during therapy with vitamin C initiated after the onset of symptoms. No significant differences from placebo were seen. Four trial comparisons involving 2753 respiratory episodes contributed to the ****-analysis of cold severity during therapy and no significant differences from placebo were seen. AUTHORS' CONCLUSIONS: The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments.

[Monger]

Interesting. Thanks for the post, Mike.

[erco]

I was always under the assumption that it makes you "feel better" and that contributes to the whole myth surrounding it as a cold cure.

Either way, I like vitamin c.

[MikeMartial]

The whole deal with vitamin C is a bit clouded with pros and cons, for and against. On one side there's Dr. Pauling, his Nobel Peace prize, and the fact he lived into his 90's with prostate cancer. Plus, it's never really been proven to do...well,...much, in megadose quantities. Then there's Berardi (among others) saying that suppressing antioxidant production may not be such a good thing.

I've flipped back and forth on both sided of the fence with this one. There was a point when I was taking up to 10g a day in divided dose. Then there was years (recently) that I took none. I'm back on 250mg x2 a day. I never really noticed a difference in anything, especially in regards to illness. The past few years I've had probably my lowest number of occurrences of colds, ever. Go figure.

[erco]

Emergen-C/Airborne > Factual backing!

I have a 2nd cousin named after Linus Pauling.

[MikeMartial]

Originally Posted by erco

Emergen-C/Airborne > Factual backing!

I have a 2nd cousin named after Linus Pauling.

Yeah, I've heard of Emergen-C. Cold-FX isn't related (it's a patented extract from North American ginseng), but they claim it's "clinically proven". When the first studies came out, their stock shot from mere cents to over 4 bucks a share, literally overnight. If you check it now, it's around 1 buck. I used to swear by it, but since I've been off it just under a year, I'm not totally convinced anymore. Maybe a healthy dose of skepticism is the key?

[erco]

Originally Posted by MikeMartial

Yeah, I've heard of Emergen-C. Cold-FX isn't related (it's a patented extract from North American ginseng), but they claim it's "clinically proven". When the first studies came out, their stock shot from mere cents to over 4 bucks a share, literally overnight. If you check it now, it's around 1 buck. I used to swear by it, but since I've been off it just under a year, I'm not totally convinced anymore. Maybe a healthy dose of skepticism is the key?

My take on Emergen-C is that even if it doesn't work, it's still a big ole healthy dose of vitamins that's pretty tastey and fizzy. I actually kinda enjoy drinking it.

[Rjkd12]

I'm also torn on the subject. There is also the idea about how we do not produce our own vitamin C, and most other mammals do. They say we "lost" one of the four enzymes to produce it, but we are the most evolved creature. So the term "lost" assumes it is beneficial to have, when nobody knows if thats true or not.

The most interesting data IMO is how most people have an upper limit of vitamin C that they can take. More than that a person will get diarrhea. This limit is normally between 2-3 grams. And its quite consistent for a given person, meaning if 2 grams is your limit, its not like one day you can take 2.5 and not get the runs. But, when a person is sick their individual limit actually increases. Someone who normally gets diarrhea on 2 grams can take 5 grams if they have the flu or something, indicating that maybe their body is utilizing that extra amount and its therefore beneficial. People who are chronically sick, like AIDS and cancer patients seem to have higher max doses than normal people also. The last argument is that when an animal that makes their own vitamin C gets sick, their body starts to produce more, which is another indication that it confers some kind of advantage.

Yet it seems like its hard to find a study that shows magadosing it is beneficial. I dunno. I tend to take anywhere from .5 grams to 2 grams a day just for the hell of it. Also, I don't put too much steak in the Pauling stuff, since he was a physicist. I think thats a bad argument based on authority. He also proposed it could cure cancer and that hasn't panned out yet.

[Monger]

Originally Posted by MikeMartial

I've flipped back and forth on both sided of the fence with this one. There was a point when I was taking up to 10g a day in divided dose. Then there was years (recently) that I took none. I'm back on 250mg x2 a day. I never really noticed a difference in anything, especially in regards to illness. The past few years I've had probably my lowest number of occurrences of colds, ever. Go figure.

The above sounds exactly like my past. I've also done the mega dosing (9-10g a day) and I've taken nothing... I didn't notice any differences. Your workout drinks could be playing a part with fewer colds in the last couple of years. I believe it was in either "Nutrient Timing" or "The Performance Zone" where they stated that carbs around intense exercise helped with preventing colds and the flu, mostly due to enhanced recovery.

[erco]

Originally Posted by Rjkd12

Yet it seems like its hard to find a study that shows magadosing it is beneficial. I dunno. I tend to take anywhere from .5 grams to 2 grams a day just for the hell of it. Also, I don't put too much steak in the Pauling stuff, since he was a physicist. I think thats a bad argument based on authority. He also proposed it could cure cancer and that hasn't panned out yet.

ehhhhhhhhh, Pauling wasn't just a physicist. Primarily, he was technically a chemist, though he did win his first Nobel Prize in an area where physics and chemistry overlap. But, he was also a noted biochemist. He was very, very close to figuring out the DNA double helix when Watson & Crick beat him, and made lots of progress in figuring out protein structures/forms.