Adjunctive micronutrient supplementation improves clinical outcomes of pulmonary tuberculosis patients

The randomized, placebo-controlled, double-blinded pilot study compared the effects of adjunctive micronutrient supplementation on the nutritional status, immune response and sputum smear conversion rates of Mexican patients being treated for pulmonary tuberculosis (TB). Newly diagnosed adult TB patients were randomized to receive vitamin A (5000 IU vitamin A/day) and zinc (50 mg zinc/day) supplements or matched placebos for four months. Both groups received the same 6-month chemotherapy short course. The results indicated that by month 2, mean plasma zinc concentrations were higher in the micronutrient than placebo group (P=0.012). The micronutrient group also had slightly but not significantly higher serum retinol levels, apparently due to the frequent consumption of  liver, eggs, and other vitamin A-rich foods by both. By month 2, subject cytokine profiles had shifted more towards a Th1 immune response noted by increasing mRNA IFN-γ and TNF-α and decreasing IL-10. This effect was more pronounced in the micronutrient group. Adjunctive micronutrient supplementation resulted in an earlier elimination of Mycobacteria bacilli from patient sputum. The proportion of micronutrient group subject who still had a positive sputum smear by month3 was significantly reduced compared to the placebo  group (7.1% vs. 46.2%; Fisher’s exact test P= 0.033). The results suggest that adjunctive supplementation improved the therapeutic effect of TB chemotherapy by improving zinc status and Th1 immune response. The effect of vitamin A supplementation was less evident.