The effect of vitamin A and zinc supplementation on treatment outcomes in pulmonary tuberculosis: a randomized controlled trial.

Randomized controlled trial in adults with smear-positive pulmonary tuberculosis treated at a primary care TB clinic in Cape Town, South Africa. Participants included people with and without HIV infection; 77 were randomized to the micronutrient arm and 66 completed the trial, while 77 were randomized to placebo and 58 completed.

Adults in the active arm received oral vitamin A as retinyl palmitate 200,000 IU capsules plus oral zinc 15 mg as zinc gluconate, given with antitubercular therapy for 2 months. The regimen was administered as part of directly observed therapy, with zinc taken 5 days per week.

Vitamin A plus zinc did not improve bacteriologic treatment outcomes or short-term clinical recovery versus placebo over 8 weeks. Sputum smear conversion was 73% with micronutrients versus 60% with placebo, and culture conversion was 65% versus 51%, but these differences were not statistically significant (P = 0.15 and P = 0.38, respectively). Time-to-detection analysis also showed no significant between-group effect (group interaction P = 0.32), and weight gain was similar at 8 weeks (2.3 kg vs 2.2 kg; P = 0.68).

The trial was short and modest in size, with differential attrition between groups that could affect precision and balance. Outcomes were limited to the first 8 weeks of therapy, so the results do not address longer-term TB outcomes. The cohort also included both HIV-infected and HIV-uninfected participants, which may add heterogeneity to interpretation.