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The article mentions zinc lozenges, and that zinc citrate may be an ineffective formulation. This is correct, but there appear to be some other problematic forms. Zinc picolinate, aspartate, erotate, and citrate all seem to be ineffective, perhaps because the wrong ionic form of zinc is released, or no ionized zinc is released. For the same reasons, flavoring of the product with sorbitol, manitol, or citric acid (or the presence of other citrate-containing compounds) renders it ineffective. It appears that zinc gluconate and zinc acetate are effective forms. Glycine is the preferred base.
Vitamin C's best study appeared in the Canadian Medical Journal (Sept. 23 1972). During 102 days in the winter, 407 people took 1 gr/day, plus 3 gr/day during the first 3 days of any illness. They were compared with 411 people taking placebo. The placebo group had 40% more ill people and 60% more doctors visits and prescription drug use.
Statistically this was highly significant but that very basic aspect of this University of Toronto study (drug use and doctors visits) was never followed up. Vitamin C would, according to this study, be to doctors what fluoride was to dentists.
Chalmers' recent reanalysis of the data (ref's 19 and 20 of the article) warrant a second if not definitive look at the use of vitamin C in the treatment of the common cold. Considering the high economic and social cost of the cold, and low mail-order price of vitamin C of about US$37/kg, such second look would be justified.
Zinc and common cold
The article mentions zinc lozenges, and that zinc citrate may be an ineffective formulation. This is correct, but there appear to be some other problematic forms. Zinc picolinate, aspartate, erotate, and citrate all seem to be ineffective, perhaps because the wrong ionic form of zinc is released, or no ionized zinc is released. For the same reasons, flavoring of the product with sorbitol, manitol, or citric acid (or the presence of other citrate-containing compounds) renders it ineffective. It appears that zinc gluconate and zinc acetate are effective forms. Glycine is the preferred base.
Competing interests: No competing interests