The Truth about Vitamin C and Colds

  • 1 Sep 2017
  • Reading time 9 mins
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A new and comprehensive analysis of studies giving vitamin C confirms that supplementation does reduce the number of colds, the severity of symptoms and the duration – but it all depends on how much you take.

To C or not to C? That is the question and one that has been hotly debated in the context of killing colds. In 1970 twice Nobel prize winner Linus Pauling, who was my teacher and patron of the Institute for Optimum Nutrition, wrote a book on vitamin C and the common cold, arguing that us primates, like the guinea pig and fruit-eating bat, cannot make vitamin C and need much more when fighting an infection.

Following this book, between 1972 and 1975, five placebo controlled studies giving 2 or more grams of vitamin C were published. [1gram(g) = 1,000milligram(mg) ]. Pooling the results together, Professor Harri Hemila from the University of Helsinki showed that ‘there was very strong evidence that colds were shorter or less severe in the vitamin C groups’ thus confirming that Pauling was right.

But the medical establishment (aka big pharma) didn’t like this and soon two ‘reviews’ came out, by Chalmers and Dykes&Meier claiming no effect. The word went out – vitamin C doesn’t work. For example the American Medical Association officially stated “One of the most widely misused vitamins is ascorbic acid. There is no reliable evidence that large doses of ascorbic acid prevents colds or shorten their duration.” They had erroneously reached this assumption by reading only these reviews, both of which had serious flaws and errors in their calculations. The main flaw was that, by including very low dose studies, down to 25mg a day, and fudging the maths, they could eliminate a statistical effect.

We are deeply indebted to Professor Harri Hemila who published this year the most comprehensive review of all studies, including a clear exposé of the flaws that were used to falsely discredit vitamin C, to tell the whole truth, and nothing but the truth about vitamin C and colds.

That’s the politics so what are the facts? What do you need to do to kill a cold?

There’s no doubt that vitamin C is gold dust for your immune system. It boosts interferon, inhibits viruses multiplying and boosts the production of immune cells, including phagocytes which attack viruses, and white blood cells (leucocytes). It is also a neuramidase inhibitor. This is the way the drug Tamiflu works. By inhibiting this enzyme viruses can’t get inside, and infect, healthy cells to take them over and become a virus factory. Vitamin C does all this and more.

When you’re under viral attack the level of vitamin C, which is highly concentrated in leucocytes, falls rapidly. Vitamin C is an antioxidant and, under viral attack, the phagocytes start to release oxidants to help destroy the virus. But they also use up vitamin C. During a cold you need about 6 grams a day to stop this decline in leucocyte vitamin C levels according to a Scottish study.

While, overall, studies above 2 grams a day do work, the best results to date have been seen in two controlled trials giving 6 to 8 grams a day on the first day of a cold. These trials have also shown that the higher dose the greater the effect. The biggest and best study, by Anderson, reported that those taking vitamin C cut the duration, measured by days confined to home, by 30%. This reduction in duration increased to 46% for those who had contact with young children.

In a more recent study of students those given 1 gram of vitamin C every hour for six hours during the first day of a cold, reported 85 per cent less cold symptoms than those taking decongestants and pain killers.

However, other studies giving lower doses of 1 gram or more have also shown a benefit in those more ‘stressed’. Five such studies– three on marathon runners, one on military personnel and one of schoolchildren in a Swiss skiing camp, all of which very doing stressful physical activity either in hot or cold conditions, had, overall half the incidence of colds. The likely explanation for this is simple. Exercise and hot/cold conditions generate more oxidants, which uses up vitamin C. The lower your levels to start with the more benefit you’re going to get, even at low doses. The same thing was found in British men. Four trials found that vitamin C decreased the incidence of colds by 30%. These studies were done in the ‘70’s or earlier when men in Britain consumed less vitamin C (up to 50mg on average) than today (average intake from diet is 100mg).

But is 6 to 8 grams enough? All studies to date have shown the higher the dose the greater the reduction in severity and duration of symptoms. So why not go higher? Case reports (not giving placebo but just variable doses of vitamin C to those with colds) have proposed that doses should be over 15 grams a day for the best effect.

This is certainly my experience. I take 2 or 3 grams immediately on the first signs of a cold and 1 gram an hour, or 2 grams every two hours, thereafter. That means I’m going to take it at least 10 to 25 grams in the first 24 hours of a cold. I have been doing this for 35 years and can ......

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