Letter to the Editor

The effect of nutrition on exercise-induced immunodepression was reviewed by Gleeson. 1 In the vitamin E section of the review, he discussed the findings of Graat et al.'s trial 2 (N = 652) with 60 year-old noninstitutionalized participants and Meydani et al.'s trial 3 (N = 617) with 65 year-old nursing home residents. Gleeson commented that self-evaluation of the common cold might have been unreliable in Graat's trial 2 ; however, Gwaltney states in a major textbook of infectious diseases that " the manifestations of the common cold are so typical and familiar that self-diagnosis by the patient is usually correct ". 4 Furthermore, even if the outcome may be inaccurate, such inaccuracy cannot explain the increase in the number of participants with fever (P = 0.009) by vitamin E supplementation in a trial that is double-blind. 2 Irrespective of etiology, the net increase in fever indicates unquestionable harm in those participants. Also, Gleeson discussed the findings of Meydani's trial. 3 Statisticians prefer intention-to-treat analysis (ITT) and in the ITT table Meydani calculated 13 different P-values, only one of which was statistically significant, but very marginally so (P = 0.048), and easily explained by the multiple comparison problem. Furthermore, even if the effect of vitamin E on the number of participants with 1 respiratory tract infection might be real, it is small (risk ratio [RR] = 0.88; 95% confidence interval [CI]: 0.76-1.00). 3 Moreover, neither of these two trials 2,3 tested whether vitamin E has effects on people carrying out exercise. A further study, not mentioned in the review, focused on the question of whether 50 mg/day of vitamin E supplementation affects the incidence of common cold in physically active 50-69 year old male smokers of the ATBC Study cohort. 5 In participants who had heavy physical activity at job (N = 2,211), vitamin E had no effect on common cold incidence (RR = 1.08; 95 % CI: 0.99-1.18), and in those who carried out heavy exercise at leisure (N = 916), vitamin E was also ineffective (RR = 1.10; 95% CI: 0.96-1.27). The effect of vitamin E on the incidence of pneumonia in physically active males was recently analyzed in the ATBC Study cohort. 6 In participants who had moderate or heavy job activity (N = 7,493), vitamin E had no effect on pneumonia risk (RR = 1.29; 95 % CI: 0.79-2.11); however, in those who carried out moderate …