Like a match to a petrol tank, the story that vitamin C can clog your arteries has set the antisupplement brigade ablaze. Follow up articles in the Daily Mail quoted the US Academy of Sciences as now concluding that there is no convincing evidence to show that taking large "amounts of antioxidants such as vitamin C or E can reduce the risks of cancer, heart disease, diabetes or Alzheimer's".
The Academy's statement, a preamble to its recommendation that there be upper limits for several of the vitamins, is now being used by the media to junk supplementation altogether. First, there was beta carotene and cancer, they say. Now it's vitamin C and furred arteries. Ergo, vitamin pills are harmful to your health.
Not surprisingly, the facts aren't anywhere near sturdy enough to manage this wholesale demolition job. First of all, the National Academy's study simply points out that there isn't enough evidence to show that "a direct connection between the intake of antioxidants and the prevention of chronic disease has yet to be effectively established". I'd quibble with that statement there are many good studies showing the benefits of taking all the antioxidants but it is true to say that far more research needs to be done, particularly in the area of optimum levels. At the moment, the National Academy's recommended upper limit of 2 g per day of vitamin C is as arbitrary as their recommended daily allowance (75 mg for women and 90 mg for men). Nobody knows what the safe upper limit is and, certainly, no one knows the optimum amount. Nutritional needs, like everything else in life, are an individual, moveable feast. What's optimum for you may be toxic for me.
The vitamin C story represents a travesty of science and scientific protocol. The fact is that there was no published paper from the USC team. The paper was under peer review at the time the story was leaked. Under the usual rules of scientific publishing, papers under review are not supposed to be circulated or publicised lest the review team rubbish the paper and recommend against publishing.
Second, the USC team used a particular imaging technique which is experimental, and is still in the midst of its own clinical trials by the National Institutes of Health in the US to determine whether it is accurate enough to be of any use in examining the state of arteries. The team also used only one of the imaging technique's indicators of arterial health the one demonstrating thickness. The other two indicators, which were not used, examine plaque index and velocity ratio, both of which would have been better able to demonstrate occlusion.
But, as the Vitamin C Foundation points out, all the study showed was that the arteries of test subjects were thicker a situation that would have been expected. "Increased vitamin C intake stimulates collagen production, but this is not well taught or well known in medical school," said a foundation spokesperson. The foundation also quotes Dr Robert Cathcart, a leading proponent of high dose vitamin C treatment, who postulates that thickening of the carotid artery with vitamin C is simply reversing the thinning that occurs with ageing.
In other words, there is no evidence that vitamin C furs up arteries, only that it strengthens thickens arterial walls.
Treatment and study of vitamins is individual and complex. As demonstrated in the case study in this issue (page 8), a single vitamin supplement taken on its own can be dangerous, particularly when dispensed by GPs who have no training in nutrition.
Vitamin supplementation represents a necessary revolution in healthy eating, necessitated by the demands of a strange new environment of approximately 20,000 chemicals in our food, air and water. It is best studied and managed by people who appreciate what human beings are up against in staying healthy in the 21st century.