Nutritional supplements for people being treated for active tuberculosis
Abstract
Background
Tuberculosis may contribute to nutritional deficiencies which in turn may delay recovery by depressing immune functions. Nutritional supplements might therefore promote recovery in people being treated for tuberculosis.
Objectives
To assess the provision of oral nutritional supplements to promote the recovery of people being treated with antituberculous drug therapy for active tuberculosis.
Search methods
We searched the Cochrane Infectious Disease Group Specialized Register (June 2008), CENTRAL (The Cochrane Library 2008, Issue 2), MEDLINE (June 2008), EMBASE (June 2008), LILACS (June 2008), mRCT (June 2008), the Indian Journal of Tuberculosis (1983 to June 2008), and checked the reference lists of all included studies.
Selection criteria
Randomized controlled trials comparing any oral nutritional supplement given for at least four weeks with no nutritional intervention, placebo, or dietary advice only for people being treated for active tuberculosis.
Data collection and analysis
Two authors independently selected trials, extracted data, and assessed risk of bias. We calculated risk ratios (RR) for dichotomous variables and mean differences (MD) for continuous variables, with 95% confidence intervals (CI). We pooled data from trials with similar interventions and outcomes.
Main results
Twelve trials (3393 participants) were included. Five trials had adequate allocation concealment. Interventions included high energy supplements, high cholesterol diet, vitamin D, vitamin A, zinc, arginine, multiple micronutrient supplements, combined multiple micronutrient supplements and zinc, combined vitamin A and zinc, and combined vitamin A and selenium. The following supplements were associated with increased body weight at follow up: high energy supplements (MD 1.73 kg, 95% CI 0.81 to 2.65; 34 participants, 1 trial); multiple micronutrients plus additional zinc (MD 2.37 kg, 95% CI 2.21 to 2.53; 192 participants, 1 trial); and vitamin A plus zinc (MD 3.10 kg, 95% CI 0.74 to 5.46; 80 participants, 1 trial). A combination of zinc and multiple micronutrients was associated with fewer deaths in HIV‐positive participants in one trial (RR 0.29, 95% CI 01.0 to 0.80, 84 participants, 1 trial). There was no evidence that any supplement affected the number of participants with sputum test positive results at the end of treatment.
Authors' conclusions
There is limited evidence that high energy supplements and some combinations of zinc with other micronutrients may help people with tuberculosis to gain weight. There is not enough evidence to assess the effect of other combinations of nutrients. A number of further trials are in progress; where appropriate, their results will be incorporated into future updates of this review.
PICOs
Plain language summary
Nutritional supplements for people being treated for active tuberculosis
Tuberculosis is a bacterial infection that mostly affects the lungs (pulmonary tuberculosis), but it can also affect the nerves, circulation, bones, and joints. It can occur in a ‘latent phase’ where people are infected but suffer no symptoms. However, with active tuberculosis the symptoms include cough, chest pain, fever, night sweats, weight loss, becoming tired easily, and sometimes people cough up blood. In people who have tuberculosis, it becomes active in about 5% to 10% of people who are HIV negative, and around 50% of people who are HIV positive. Tuberculosis is treated with a combination antibiotic drugs that must be taken for a period of at least six months to ensure success. If left untreated, around half of those with active tuberculosis will die of the disease. This review looked to see whether nutritional supplements might help people to recover better when they were being treated for tuberculosis. The review identified 12 trials involving 3393 people, mostly adults. The trials covered many different nutritional supplements and provided only limited evidence that supplements may help. High energy supplements, multiple micronutrients combined with zinc and zinc combined with vitamin A showed promise. Also the combination of zinc and multiple micronutrients may reduce the number of people with tuberculosis who are also HIV positive who die. There was not enough evidence available to assess fully the effectiveness of any other combination of nutrients. Further trials are needed that are large enough, conducted in areas where tuberculosis is prevalent, and assess the supplements that have shown promise in these initial studies.
