Protein-calorie malnutrition, macronutrient supplements, and tuberculosis

BACKGROUND: Protein-calorie malnutrition (PCM) is a risk factor for tuberculosis (TB) disease and may affect treatment outcomes. There is currently no recommended macronutrient intervention for improving the outcome of anti-tuberculosis treatment. METHODS: We reviewed current literature on PCM and low body mass index (BMI) as risk factors for tuberculous infection and TB disease, and their effects on anti-tuberculosis treatment. We summarize clinical trials of macronutrient supplementation in the treatment of TB. RESULTS: PCM is a well-established risk factor for TB disease; however, data on malnutrition and the risk of tuberculous infection are limited. Malnutrition is associated with an increased risk of mortality and relapse of active TB. Clinical trials of macronutrient supplementation during treatment confirm a 2-3 kg improvement in weight gain at 2 months, and may result in improvement in physical function, sputum conversion and treatment completion, but they have not been powered to assess effects on mortality or relapse. CONCLUSION: Assessment of dietary intake, food security, and baseline BMI should be standard practice in anti-tuberculosis treatment, along with dietary counselling. As macronutrient supplementation may have modest benefits and is not associated with adverse events, patients with BMI values <18.5 kg/m(2) should be provided with balanced macronutrient supplementation whenever possible.