Their next great insight was that animals don’t get atherosclerosis because they possess an enzyme that converts glucose into vitamin C in their liver.

To test this theory, Rath and Pauling used one of the few animals that, like humans, cannot make its own vitamin C - the guinea pig. These animals were all given an identical high-fat diet, but some also received 40 mg/day of vitamin C (the equivalent to 5 g/day for a human). Five weeks later, the animals lacking vitamin C had developed severe atherosclerosis, whereas those taking vitamin C were totally clear (Proc Natl Acad Sci USA, 1990; 87: 9388-90). The finding that vitamin C stimulates the production of collagen provided the final clinching piece of evidence (Biochem Cell Biol, 1990; 68: 1166-73).

Rath and Pauling arrived at two totally revolutionary conclusions: (1) Self-made vitamin C maintains healthy arteries in animals, virtually no matter the diet, by bolstering arterial collagen; (2) If deprived of vitamin C, the body uses the lipoprotein in cholesterol to repair damaged arteries.

Thus, atherosclerosis in humans and guinea pigs is due to vitamin C deficiency. In short, heart disease is “chronic scurvy” (Proc Natl Acad Sci USA, 1990; 87: 6204-7).

Predictably, despite Pauling’s preeminence as the ‘father of modern chemistry’, the medical profession dismissed his extraordinary radical ideas out of hand.

Yet, within a few years, the supporting evidence began to surface. In 1992, a major study of over 11,000 Americans showed that those with the highest intakes of vitamin C had almost half the rate of heart disease (Epidemiology, 1992; 3: 194-202). Although some subsequent studies failed to find any benefit from vitamin C, on balance, the latest evidence appears to vindicate Pauling’s thesis. Most recently, data from nearly 300,000 people show conclusively that an intake of 700 mg/day or more of vitamin C reduces the risk of heart disease by 25 per cent (Am J Clin Nutr, 2004; 80: 1508-20).

But there’s a puzzle. According to Pauling’s theory, no one taking enough vitamin C should get heart disease at all. So, why should the risk be reduced by only a quarter with 700 mg/day of the vitamin - a massive 10 times the RDA?

The answer appears to be that even this huge dose is inadequate (see box above).

Here again, the clue comes from animals, which naturally produce huge amounts of vitamin C. A 70-kg goat makes about 13,000 mg (13 g) of vitamin C every day, a large dog about 2.5 g/day. The Committee on Animal Nutrition has also shown that monkeys (which, like us, can’t produce their own vitamin C) need around 55 mg/kg body weight/day of vitamin C for optimal health. In human terms, this means an average 70-kg person needs to take nearly 4 g/day.

Reversing disease It’s even possible that very high-dose vitamin C might actually reverse heart disease. Curiously, the only trials to test this theory were done 50 years ago by Canadian physician Dr G.C. Willis.

Willis was an atherosclerosis expert and had pioneered angiography (the now widespread method of photographing arteries using X-rays). What he saw convinced him that the conventional explanation for atherosclerosis was wrong - so wrong that even a plumber could see it.

If the condition was due to a build-up of cholesterol in the blood, the narrowest arteries should be the first affected, just as sludge builds up more quickly in narrow water pipes. In fact, the opposite is true in the body - the biggest arteries tend to fur up first.