Within a month of a Codex meeting last autumn that announced a deadline for establishing safe upper levels for vitamins, a couple of high-profile studies have questioned high doses of cornerstone nutrients.
The timing of the now-infamous vitamin E analysis, as well as another on vitamin C, has left many in the industry braced for further attacks on the safety record of supplements in the run-up to the July deadline, when the international Codex body is due to submit its final recommendations for safe upper levels for vitamins.
?I think we are in for another round of attacks on vitamins based on this crude analysis of vitamin E, with some medical experts calling for restrictions on vitamin potency,? said Neil E Levin, nutrition educator at Illinois-based manufacturer Now Foods. ?These meta-analyses are by no means definitive proof of anything, due to the lack of uniform protocols and patient groups. But that won?t stop the medical lobby from trying to use these results to limit potencies of vitamins to everyone ?for our own good?.?
The impact of the study has been felt in Europe where a flood of negative media coverage in the UK prompted the Health Food Manufacturers Association to issue a release accusing the authors of ?distorting? the results that the association says have been compounded by ?grossly simplified reporting in some UK media.?
Codex wields enormous influence as far as harmonising regulations around the world. Current US guidelines set an upper tolerable intake limit of vitamin E at 1,500IU per day. The study?s authors believe that should be revised downward.
?Policy makers and government regulators should consider lowering this level, perhaps, to an upper limit of 400IU per day,? said Eliseo Guallar, MD, PhD, senior author of the study and assistant professor of epidemiology at the Bloomberg School of Public Health. ?On the basis of our study, high-dosage vitamin E supplementation is clearly unjustified.?
The study re-analysed 19 studies of vitamin E between 1993 and 2004. Although 18 of the 19 had data that was statistically insignificant on any vitamin E effect — and none of the original studies had all-cause mortality as a primary endpoint — the combined cohort gave greater statistical power to the overall results. Most of the trials involved middle-aged to elderly persons who had heart disease or other serious conditions or were at risk of disease.
?It is shocking how, on the basis of flimsy findings, such sweeping and definitive pronouncements are being made,? said James J Gormley, policy advisor for Citizens for Health. ?A number of landmark epidemiological studies have, in fact, established that vitamin E supplementation reduces cardiovascular disease progression, and, in fact, improves mortality.?
He cited several examples including the Nurses? Health Study of 87,000 nurses, which found 31 per cent reduction of risk of nonfatal infarction as well as death from cardiovascular disease compared to those who did not supplement.
A great concern for industry is that when Codex sets limits, it will take years of overwhelming scientific data to change its recommendations — and even longer for individual governments to change their national regulations.