Need help debunking Vitamin C megadosing

[Paradox74]

After getting hay fever, a friend of mine suggested megadosing on Vitamin C. With work keeping me down, I am unable to comb through the net searching for information that might help to correct my friend's misconceptions about this alternative medicine fad.

I know about that Skeptoid episode, but do you know of any other articles, videos or podcasts that talk about this issue?

Thanks in advance.

 

[Emet]

The Vitamin C Myth

February 2, 2006
There's no doubt that Vitamin C is good for you. But, contrary to popular belief, a mega-dose of Vitamin C is not an effective cold remedy.

http://www.npr.org/templates/story/story.php?storyId=5184850

The Dark Side of Linus Pauling's Legacy

Stephen Barrett, M.D.

http://www.quackwatch.com/01QuackeryRelatedTopics/pauling.html

Treating The Common Cold
(...)
Vitamin C has been a favorite since Linus Pauling promoted in decades ago. But decades of research has not been kind to this claim. The research has failed to find a consistent and convincing effect for vitamin C in treating or preventing the common cold. For routine prevention, the evidence is dead negative. For treating an acute infection, there is mixed evidence for a possible very mild benefit, but this is likely just noise in the research.

http://www.sciencebasedmedicine.org/?p=10823

Vitamin C megadosage (Wiki page):

http://en.wikipedia.org/wiki/Vitamin_C_megadosage

 

[NoZed Avenger]

Vitamin C is not a vitamin that is retained by your body, as I understand it.

Meaning all of that excess Vitamin C is simply expelled on your next visit to the bathroom. Since it doesn't stay in the system, how is it supposed to work its magic?

 

[icerat]

Anecdotal I know, but I used to take a tablet of ascorbic acid blended with a concentrate of acerola cherries, which is high in vitamin C, and it certainly felt like it help my allergies. Nowhere near a megadose amount though.

There has been quite a bit of research indicating a possible link between Vitamin C levels and inflammation (one example), so it's not an entirely wild hypothesis.

btw it's possible to get slow release Vitamin C tablets these days, so you don't just pee out all the excess. I'm not aware of any megadose versions though, so they're probably still just a way to make expensive pee.

 

[dlorde]

Anecdotal I know, but I used to take a tablet of ascorbic acid blended with a concentrate of acerola cherries, which is high in vitamin C, and it certainly felt like it help my allergies. Nowhere near a megadose amount though.

Some good friends of mine say the same kind of thing about homeopathic remedies...

 

[icerat]

Some good friends of mine say the same kind of thing about homeopathic remedies...

Do they have quality peer reviewed journal articles showing a link between homeopathic preparations and inflammation?

While it's a bit all over the place, there is extensive literature on vitamin C and inflammation.

Things like chronic rhinosinusitis are essentially problems of inflammation (source)

I linked earlier to this 2009 placebo controlled study which indicated supplementation of 1000mg of Vitamin C lowered blood serum CRP levels, one marker of inflammation.

This double blind placebo study found a significant effect of Vitamin C as a treatment for allergic rhinitis.

Alas it's an area that hasn't been well studied, and when it has it's been with wildly differing experimental design. Still, if allergies are linked to inflammation, and Vitamin C has an effect on inflammation, then there's a plausible mechanism, even if we don't know what it is.

I'd like to see that from your "good friends" homeopathic remedies

With regard the OP, dietary supplement dosages of around 300mg seem to have little effect, 1000mg might have an effect, larger megadoses may have a pro-inflammatory effect, particularly after exercise.

 

[Emet]

This double blind placebo study found a significant effect of Vitamin C as a treatment for allergic rhinitis.

Abstract
The effect of acute oral administration of 2 g vitamin C on bronchial responsiveness to inhaled histamine in 16 patients with allergic rhinitis was compared with placebo on two consecutive days in a double-blind, crossover design. The PC15FEV1 was significantly increased one hour after treatment with vitamin C but not after placebo.

This is an effective treatment for allergic rhinitis?

EDITORIAL
Is vitamin C an antiinflammatory agent?1,2,3
(...)
If it is true, as Wannamethee et al concluded, that vitamin C has antiinflammatory effects, then that finding should be borne out in prospective supplementation studies. A review of the prospective studies to date found that 4 of the 5 studies with doses ranging from 250 to 3000 mg vitamin C/d in persons with diabetes, hypercholesterolemia, hemodialysis, or coronary artery disease reported no antiinflammatory effect (5–9). Block et al (5) found a reduction in CRP in active and passive smokers with intakes of 515 mg vitamin C/d. Thus, in summarizing the prospective studies, one cannot arrive at a firm conclusion that vitamin C is antiinflammatory, and indeed most of the studies would support the notion that vitamin C is not antiinflammatory (5–8).
(...)
In conclusion, whereas the study by Wannamethee et al is provocative with respect to the antiinflammatory effects of vitamin C, it does not allow the drawing of any valid conclusions. Much further research in a dose-response structure is required to ascertain whether oral vitamin C supplementation is antiinflammatory and whether it improves endothelial dysfunction. Until such studies have been conducted, it is safe to adhere to the guidelines of national organizations to consume ≥5 daily servings of fruit and vegetables.

http://www.ajcn.org/content/83/3/525.full

 

[icerat]

This is an effective treatment for allergic rhinitis?

That's what it says, yes.

As I said though, it's an area that hasn't been well studied and results are a bit over the place. From the editorial you quoted -

Much further research in a dose-response structure is required to ascertain whether oral vitamin C supplementation is antiinflammatory and whether it improves endothelial dysfunction.

The editorial predates for example the 2009 study I linked to.

A 2008 paper, Inflammation in the vascular bed: Importance of vitamin C points out that there is a wealth of in vitro studies showing an effect, but the kind of studies your editorial cited (ie on people already with serious disease) may be a matter of "too little too late"

Some more recent studies -

This 2010 study found a significant anti-inflammatory effect in mice from a E/C blend.

This 2008 study also found a significant post-surgery anti-inflammatory effect from an E/C supplement

This 2009 study and
this 2010 study again confirmed anti-inflammatory effects, the later suggesting it as a supplementary asthma treatment.

Not exactly in the realm of homeopathy research is it?

 

[Emet]

Not exactly in the realm of homeopathy research is it?

I presume you're speaking to another poster, as I never compared it to homeopathic research.

Most of the studies you linked to are interesting, and I'm certainly no expert in evaluating them, especially when they're merely abstracts.

But I'm not convinced that there is any good evidence that supplementing with Vitamin C is all that useful for most people, at least at this time.

In vitro or animal research often does not pan out.

I often look to Science-based Medicine as a valuable resource for evaluation of studies, and current recommendations. I think they are better qualified than either of us, as a rule. Please do not think that I am suggesting they are infallible, or the final authority on anything.

Another Negative Study of Vitamins

Routine Supplementation
(...)
The question of routine supplementation, however, goes further. It asks whether or not taking vitamin supplements are necessary or helpful for someone who has a reasonable diet and does not have any specific disease or condition that would impact their demand for specific vitamins – i.e. routine.
(...)
Right now the evidence supports the conclusion that for most people who have a reasonable diet there is no benefit from routine supplementation.
(...)
Targeted Supplementation

None of what I said above has anything to do with targeted supplementation. I prescribe vitamins almost every day – for those with conditions known to be improved or prevented by specific vitamins or co-factors, and for those with a documented deficiency.
(...)
Conclusion

There is a clear trend in the evidence we have to date. The benefits of routine supplementation are unproven. High doses of vitamins probably cause more harm than good. If you are concerned about your nutrition then improve your diet.

Further, as with good science-based medicine in general, questions must be specific. We should not ask – do vitamins work. Rather we need to consider specific supplementation in specific situations and conditions.

http://www.sciencebasedmedicine.org/?p=372

Despite the dates of any studies you may have linked to that post-date the above article, I think their major points still stand.

 

[Unlike a Bull]

Abstract

The effect of acute oral administration of 2 g vitamin C on bronchial responsiveness to inhaled histamine in 16 patients with allergic rhinitis was compared with placebo on two consecutive days in a double-blind, crossover design. The PC15FEV1 was significantly increased one hour after treatment with vitamin C but not after placebo.

I have no idea what this means. What is PC15FEV1?

 

[Unlike a Bull]

Also, even if vitamin C acts as an anti-inflammatory, would this reduce the chance of getting the cold, or reduce the duration of the cold? I can see it reducing some of the symptoms associated with swollen membranes, sinuses, or bronchioles, but how would this compare to something like ibuprofen which also reduces fever and lessens pain? What is the cost difference between ibuprofen and vitamin C? What are the risks associated with each?

 

[icerat]

Emet,

The SBM article you cited (which while overall sensible has a number of errors of fact) didn't event talk about Vitamin C and inflammation, so I'm not sure why you quoted it?

Are you claiming a study on multivitamin use (with no discrimination at all in what that actually covers) in post-menopausal women is relevant to research on Vitamin C and inflammation?

We have a biological basis to believe that Vitamin C plays a role in inflammation control

We have in vitro studies supporting this

We have placebo control studies in humans supporting this.

It's therefore not unreasonable to hypothesis that vitamin C supplementation may help alleviate the symptoms of allergies - and indeed we have some studies supporting this. This is a specific case, and not "most people".

Just because there's a lack of quality research, and no lack of BS claims, doesn't mean the idea should be dismissed. Much clinical research in the nutrition field is unfortunately poor and shows a lack of understanding of the biological underpinnings of the field. For example you'll regularly see studies on Omega-3 supplementation ... but virtually none of them control for Omega-6 intake, which makes them predictably very hit and miss affairs.

 

[icerat]

I have no idea what this means. What is PC15FEV1?

It's a measure of how the airways are effected by histamines, ie allergens. An increased PC15=Percentage 15 FEV1=Forced Expiry Volume in 1 Second.

Roughly, an increased PC15FEV1 means you need more allergans to achieve a worsening of the airways

Also, even if vitamin C acts as an anti-inflammatory, would this reduce the chance of getting the cold, or reduce the duration of the cold?

There's some research showing a decrease in duration of colds from C supplementation, but it's not a strong effect. Indeed what it may be is an alleviation of symptoms rather than "cure" per se, so people are self reporting they feel better.

I can see it reducing some of the symptoms associated with swollen membranes, sinuses, or bronchioles, but how would this compare to something like ibuprofen which also reduces fever and lessens pain? What is the cost difference between ibuprofen and vitamin C? What are the risks associated with each?

Not much risk involved with either, though large amounts of either can be fatal. Ibuprofen is pain relief as well as anti-inflammatory. While there's been some anecdotal reports of high doses of vitamin C offering pain relief there's not much research into this and I don't put a lot of weight in the reports I have read.

 

[Tatyana]

Do they have quality peer reviewed journal articles showing a link between homeopathic preparations and inflammation?

While it's a bit all over the place, there is extensive literature on vitamin C and inflammation.

Things like chronic rhinosinusitis are essentially problems of inflammation (source)

I linked earlier to this 2009 placebo controlled study which indicated supplementation of 1000mg of Vitamin C lowered blood serum CRP levels, one marker of inflammation.

This double blind placebo study found a significant effect of Vitamin C as a treatment for allergic rhinitis.

Alas it's an area that hasn't been well studied, and when it has it's been with wildly differing experimental design. Still, if allergies are linked to inflammation, and Vitamin C has an effect on inflammation, then there's a plausible mechanism, even if we don't know what it is.

I'd like to see that from your "good friends" homeopathic remedies

With regard the OP, dietary supplement dosages of around 300mg seem to have little effect, 1000mg might have an effect, larger megadoses may have a pro-inflammatory effect, particularly after exercise.

CRP is such a non-specific marker of inflammation AND infection that most medics state that you had might as well add an 'A' in the middle of CRP.

I think when it comes to things like allergies, they are called hypersensitivity reactions, inflammation isn't precise enough in the domain of immunological research, however, it is the best way to explain it to the general public.

I hate to break this to you, but for some reason, maybe it is because immunology is relatively new field and we don't entirely understand all the complicated nuances of the immune system, most immunology research is really, really, really bad.

 

[icerat]

btw, I'd point out the OP was asking about hayfever relief, not a cold.

 

[icerat]

CRP is such a non-specific marker of inflammation AND infection that most medics state that you had might as well add an 'A' in the middle of CRP.

That why I said "one" marker and also pointed out, more than once, a need for more research. Some of the other studies I cited had far more specific measurements.

I think when it comes to things like allergies, they are called hypersensitivity reactions, inflammation isn't precise enough in the domain of immunological research, however, it is the best way to explain it to the general public.

I hate to break this to you, but for some reason, maybe it is because immunology is relatively new field and we don't entirely understand all the complicated nuances of the immune system, most immunology research is really, really, really bad.

It's not that new, while not my field I was working with immunology researchers more than 2 decades ago.

There's pretty good in vitro type work being done, but at a more practical level I agree, all over the place.

In any case, my point was that (a) research indicates there may be something to it, but more study is needed (b) I personally have experienced apparent benefits (though even if real it may have been from some other factor in the acerola concentrate) and (c) it certainly isn't in the realm of homeopathy, as dlorde suggested

 

[Unlike a Bull]

It's a measure of how the airways are effected by histamines, ie allergens. An increased PC15=Percentage 15 FEV1=Forced Expiry Volume in 1 Second.

Roughly, an increased PC15FEV1 means you need more allergans to achieve a worsening of the airways

I see. Thanks, man.

 

[Tatyana]

That why I said "one" marker and also pointed out, more than once, a need for more research. Some of the other studies I cited had far more specific measurements.



It's not that new, while not my field I was working with immunology researchers more than 2 decades ago.

There's pretty good in vitro type work being done, but at a more practical level I agree, all over the place.

In any case, my point was that (a) research indicates there may be something to it, but more study is needed (b) I personally have experienced apparent benefits (though even if real it may have been from some other factor in the acerola concentrate) and (c) it certainly isn't in the realm of homeopathy, as dlorde suggested

Research almost always states 'more study is required'.

Just to reiterate the whole CRP thing, it is an acute phase protein, which is a part of the innate immune response, whereas hypersensitivity reactions/allergies, are a part of the acquired or cell-mediated response.

It is sort of like measuring glucose for renal failure, they are related, but it isn't particularly relevant.

I will have a closer look at each of the studies, however, the majority of studies on vitamin superdosing indicate that they do far more harm than good.

 

[sadhatter]

We have actually been studing this in my college course recently, so to chime in with the general consensus from what we have been taught.

Vitamin c, is obviously good at the appropriate levels, and keeps things " on track" as the case may be. You don't want to be lacking.

But gigantic doses, and all of the magical benefits that go along with them, are just like any other kind of magic.

As a matter of fact, Vitamin C, when consumed in copious quantities, can cause issues that may not be permanent, or lethal, but are a solid 6/10 on the unpleasant scale ( obviously not a technical medical term, lol.). Diarrhea , upset stomach, and general low level GI issues are becoming more and more common as people come into the pharmacy after saturating themselves with vitamin C.

While excess is simply passed, the build up and your stomach do not really get along well.

 

[Crocoshark]

This is a pretty cool chart I found yesterday giving the harmful side effects of various natural substances in high doses, vitamins included

http://1stholistic.com/nutrition/hol_nutr-toxic-dosages.htm