I read with interest the recent article by Christen et al.1 The study has a serious flaw in its design regarding its assessment of treatment with vitamin E to reduce the incidence of age-related cataracts. This study evaluated the effect of synthetic vitamin E at a dose of 400 IU every other day. Natural vitamin E (RRR-d-α- tocopherol acetate) has approximately twice the bioavailability compared with synthetic vitamin E (all- rac -α-tocopherol).2 Recently the clinical pharmacology of vitamin E has been defined.3 The study showed that a daily dose of a minimum of 1600 IU of natural vitamin E is required to significantly lower levels of lipid peroxidation in humans, which would be equivalent to a daily dose of 3200 IU of synthetic vitamin E. Thus, the dose of vitamin E tested in the Christen et al study1 would not be expected to diminish the level of photoperoxidation of lens cell membranes and prevent cataract formation.
L. Jackson Roberts. Vitamin E and Age-Related Cataracts. Arch Ophthalmol. 2011;129(6):805–820. doi:10.1001/archophthalmol.2011.106