Imagine that a deadly virus is sweeping the world, killing and maiming hundreds of thousands of children. Nothing seems able to stop it - until a doctor stands up at the American Medical Association and reports on 60 cases involving severely infected children, all of whom have been cured. Yet his work, subsequently reported in a peer-review journal, is ignored, leaving the virus to wreak havoc for decades.

This isn't a docudrama about some futuristic plague - it's a true story about what happened in June 1949 when polio was at its peak. Dr Frederick Klenner, a clinical researcher from Reidsville, North Carolina, reported that a massive intravenous dose of Vitamin C - up to 20,000mg daily for three days (today's recommended daily allowance is 60mg) - had cured 60 of his patients. The findings were published in a medical journal, yet there was virtually no interest. Apart from a couple of minor trials, no attempt was made to find out if they had any scientific substance.

Relating this curious incident in a new book, Vitamin C, Infectious Diseases & Toxins: Curing the Incurable, Dr Thomas Levy, a US cardiologist, admits to being gripped by a range of emotions when he came across Klenner's work and other studies that replicated it. "To know that polio had been easily cured yet so many people continued to die, or survived to be permanently crippled by it, was difficult to accept."

Levy argues that the medical profession has routinely ignored research showing that high doses of Vitamin C can combat bacteria, toxins and severe viral infections including avian flu, SARS, hepatitis and herpes. And this is not a case of doctors sniffing at anecdotal evidence from a handful of enthusiasts. "Vitamin C is possibly the best-researched substance in the world. There are more than 24,000 papers and articles on the authoritative clinical website, Medline. Yet virtually the all the evidence has been dismissed." Levy even claims that Aids can be controlled if a high enough dosage of Vitamin C is maintained.

This is not the first time doctors have had their cages rattled over the benefits of Vitamin C. The controversy has been simmering since 1753, when just a couple of sucks of a lime were shown to prevent scurvy. In the 1950s the chemist Linus Pauling, a double Nobel prize-winner, promoted the use of mega-doses of Vitamin C, but his research was rubbished by clinicians.

Recently, the anti-Vitamin C sentiment has grown. It has been blamed for causing the formation of kidney stones, and a study published in the journal Science in 2001 found that even 200mg doses of Vitamin C "facilitated the production of DNA-damaging agents associated with a variety of cancers". This finding was widely interpreted as proving that Vitamin C causes cancer.

Britain's Food Standards Agency recommends taking a maximum of 1,000mg of Vitamin C a day. But a directive going through the European Parliament aims to reduce this to less than 100mg in an attempt to harmonise dosages across the Continent. Despite being dubbed "illegal" by the advocate general of the European Court of Justice last week, the directive could still be passed.

The controversy has not put off consumers, many of whom take Vitamin C to ward off colds. The 1,000 mg capsule is the most popular single vitamin in Britain, with the 500mg version second.

Some people argue that we can get sufficient Vitamin C from a diet rich in fruit and vegetables, but Levy disagrees. The problem, he says, is that a genetic design fault makes us unable to synthesise our own Vitamin C. Levy claims that while recommended daily allowances of 60mg are enough to prevent the development of scurvy in otherwise healthy people, much higher levels are required to maintain health when an infection strikes. At such times, the body begins to "metabolise unusually large amounts of vitamin C, keeping stores so depleted that the recommended daily allowance will not even prevent many of the symptoms of scurvy from developing".

Levy claims that the reason why most animals stay healthy throughout their lives, while humans spend years coping with one or more chronic diseases, is that animals make their own Vitamin C. The wild goat, for instance, makes around 13,000mg a day, rising to 100,000mg when faced with life-threatening infectious or toxic stress, according to a 1961 study published in the Annals of the New York Academy of Sciences.

So, is Levy right? Should everyone be taking mega-doses every day and having intravenous infusions when they fall ill? Possibly.

Dr Rodney Adeniyi-Jones regularly gives 20,000mg doses to people with arterial disease and as part of a flu treatment protocol, describing its effects as "beneficial... but not miraculous". And Professor George Lewith of the Centre for Complementary and Integrated Medicine says that while Vitamin C is not a panacea, it does have clinical benefits depending on the dosage. "There may be doses that are therapeutic, while another dose may be damaging for the same condition. It is not a dose-response curve as with pharmaceuticals, and we need to be cautious until this is better understood."

But he also warns that: "Many of the [Vitamin C] trials have been badly done and what evidence exists is mixed. Both those in favour and against high doses frequently misinterpret the data."

Levy may well be seen to have an axe to grind, yet the evidence seems to support his view that apart from causing diarrhoea, mega-doses of Vitamin C are not toxic. He says that a series of studies published in leading journals have shown that, far from causing cancer, Vitamin C is a safe supplement for chronic cancer patients. Further large studies suggest that supplements do not put a normal person at greater risk of developing kidney stones.

According to Levy, the problem is not that people might take too much, but that they won't take enough - and thus won't get the desired effects. "There's a popular medical view that taking Vitamin C just makes expensive urine. Some of it is lost in urine, but the more you consume, the more stays in your body."

With a new book on the way claiming that Vitamin C deficiency is also a primary cause of cardiovascular disease, Levy cannot be accused of underselling his case. Nor can he overcome the fact that proper clinical trials are still desperately needed. Considering its overall safety, there appears to be no good reason why anyone with a chronic or acute health problem should not try, at the very least, a couple of week's regime of two or three 1,000mg tablets of Vitamin C a day.

Need to Know: So how much should you take?

For a cold - Three 1,000mg doses a day, according to the campaign group Consumers for Health Choice.

For flu - Although it's more serious, the viral load is similar, according to research, and taking up to 20,000mg a day could be beneficial.

For shingles - Research has shown that this painful post-viral condition can be pretty well cured by an injection of 3,000mg of vitamin C. Taking four 1,000mg tablets orally for three days could be worthwhile as well.

For a hangover - Taking 1,000mg daily in the week before a booze-up reduces stress on the liver. If you're drunk and want to look sober, a large dose of vitamin C will prevent drunken behaviour, according to a 1986 study, "Alcohol and Alcoholism".

To maintain your health - A 1,000mg daily dose is regarded as safe by the Food Standards Agency, and adequate to keep sufficient vitamin C in the plasma and tissues. "We believe this is absolutely safe and definitely beneficial to people's health," says Sue Croft of Consumers for Health Choice.

©2005 Independent News & Media (UK) Ltd.
http://news.independent.co.uk/uk/health_medical/story.jsp?story=628538

• Dr. Klenner's Clinical Guide to the Use of Vitamin C is now posted in its entirety at http://www.seanet.com/~alexs/ascorbate/198x/smith-lh-clinical_guide_1988.htm

• The complete text of Irwin Stone's book The Healing Factor is now posted for free reading at http://vitamincfoundation.org/stone/

• Dr. Robert Cathcart