Addressing tuberculosis in the context of malnutrition and HIV coinfection

Background. Tuberculosis is the second leading cause of infectious disease mortality (1.8 million/year), after HIV/AIDS. There are more than 9 million new cases each year. One-third of the world's population, and 50% of adults in sub-Saharan Africa, South Asia, and South-East Asia, are infected, representing an enormous pool of individuals at risk for developing the disease. The situation is complicated by the HIV/AIDS pandemic, widespread undernutrition, smoking, diabetes, increased mobility, and emergence of multi- and extensively drug-resistant tuberculosis. Objective. To review the scientific evidence about the interactions among tuberculosis, nutrition, and HIV coinfection. Results. HIV infection and malnutrition lower immunity, increasing the risk of reactivation tuberculosis and primary progressive disease. Having either tuberculosis or HIV infection causes weight loss. Malnutrition markedly increases mortality among both tuberculosis and HIV/AIDS patients and should be treated concurrently with treatment of the infections. Tuberculosis treatment is a prerequisite for nutritional recovery, in addition to intake of nutrients required for rebuilding tissues, which is constrained in food-insecure households. Additional pharmaceutical treatment to reduce the catabolic impact of inflammation or promote growth may be needed. Specific nutrients can contribute to faster sputum smear clearance, which is important for reducing transmission, as well as faster weight gain when combined with an adequate diet. Adequate nutrition and weight gain in undernourished populations might reduce the incidence of tuberculosis. Conclusions. The many risk factors for the development of tuberculosis need to be addressed simultaneously, especially HIV/AIDS and food insecurity and undernutrition. For stronger evidence-based guidelines, existing recommendations and clinical applications need to be more widely applied and evaluated.