The effect of micronutrient supplementation on treatment outcome in patients with pulmonary tuberculosis : a randomized controlled trial in Mwanza, Tanzania

OBJECTIVE The aim of the study was to assess the effects of micronutrient supplementation on culture conversion in tuberculosis (TB) patients. DESIGN The study was a randomized, double-blind placebo-controlled 2 x 2 trial of zinc and multi-micronutrient (MMN) supplementation in pulmonary TB patients in Tanzania. RESULTS A total of 499 pulmonary TB patients were included in the trial after being confirmed sputum-positive by microscopy or culture. At 8 weeks, 25% were sputum-smear positive but only 11% were culture-positive (P < 0.0001). No significant differences were observed in culture conversion rate among those allocated to MMN or placebo (89.5 vs. 86.2%, P = 0.29) at 8 weeks, although at week 4 those allocated to MMN had a slightly reduced culture conversion rate (42.8 vs. 52.8%, P = 0.058). Zinc had no effects on culture conversion. MMN increased weight gain by 0.78 kg [95% confidence interval (CI): 0.12-1.43] at week 8, while zinc supplementation had no effect. The effects of MMN and zinc did not interact and neither MMN nor zinc interacted with human immunodeficiency virus status, sex and culture-intensity at baseline. CONCLUSION Neither zinc nor MMN supplementation had significant effects on culture conversion, but MMN supplementation increased weight gain in TB patients.