Vitamin C Function

JSK 252

Hi! First time I have ever posted in this forum! Its about time I did!

Just wanted to know if vitamin C is involved in boosting Immune function because my biology teacher ( Im in 5th year by the way) said that it doesnt.

Kevster

I did Biochemistry last year in college (got 96% ) and never read that Vitamin C boosts immunity. That's not to say that it doesn't because it's difficult to completely map the function of vitamins & minerals. They appear to have many advantageous effects that we are still discovering.

Vitamin C (or Ascorbic Acid) has mainly been documented to prevent skin lesions, fragile blood vessels, loose teeth, and bleeding gums (i.e. - the symptoms of 'Scurvy'). It can be synthesised by most animals, but not primates (monkeys, apes, and thus 'us'). Therefore, we need to obtain it in our diet, which you already knew.

Kevin.

Vorsprung

Yea good question, I was wondering about this the other day!

A quick PubMed search gave this paper, from which I read this:

Summary
Clearly the essentiality of vitamin C to cells of the immune system has been established. Although not all clinical data agree with an effect of vitamin C on viral infections, there is convincing evidence from feeding studies in humans and animals and experiments done on primary cultures that vitamin C has a positive effect on host defense. Unfortunately, we are far from being able to define the optimal levels of intake required to maintain an optimal immune response to prevent or treat viral or other infectious diseases.

There's a fair few review articles on the subject. I've heard anecdotally that some amount (can't remember how much) taken 2 hourly helps against cold/flu symptoms, but not sure if there's any evidence for it.

Schlemm

I heard of an interesting study that showed that people who take large doses (well above the reccomended daily allowance or RDA) of vitamin c over a long period of time tend to adapt to a 'new' higher RDA, and once they went back to the normal RDA which is reccomended it was insufficient for them...makes you wonder about routine use of high dose (eg 500mg) vit c tabs...!

Vorsprung

Looks like the Cochrane crew had a look at it:

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 shows that it could be justified in persons exposed to brief periods of severe physical exercise and/or cold environments. Also, the consistent and statistically significant small benefits on duration and severity for those using regular vitamin C prophylaxis indicates that vitamin C plays some role in respiratory defence mechanisms. The trials in which vitamin C was introduced at the onset of colds as therapy did not show any benefit in doses up to 4 grams daily, but one large trial reported equivocal benefit from an 8 gram therapeutic dose at onset of symptoms.

Pub Med link to full abstract

DrIndy

remember too that people who take large doses of vitamin c develop diaorrhea. also there is a phenomenon of rebound scurvy where a high dose long term vitamin C user stops suddenly and then they develop scurvy as a result!

oneeyedsnake

Vitamin C levels are know to fall when you get colds.I'm not sure if you get a cold because your vitamin c level has fallen or if it's just a symptom of the cold its self.Personaly I just try to eat 5 friuts a day along with a half liter of orange juice.