Micronutrient Deficiency and Tuberculosis

Tuberculosis remains a significant public health problem throughout the world. 1.7 billion people or approximately one third of the world’s population are infected with Mycobacterium tuberculosis. During the 1990s, an estimated 30 million people died as a result of TB, resulting in the observation that TB may be the most important pathogen in the world today. HIV has added synergistically to the scourge of tuberculosis, with rates of HIV associated TB increasing dramatically in the late 1980s and early 1990s. In addition, poor adherence, dismantling of the public health infrastructure, inadequate supervision of TB medication administration, had resulted in significant rates of multidrug resistant TB in cities in the US, such as NYC, and also throughout the world, most prominent in Russia (>20% in the prison system) and the Dominican Republic. In the days when the sanitarium was the only treatment for tuberculosis, a great deal of emphasis was placed on nutrition, nutritional supplementation (cod liver oil,) and sunlight and fresh air. Since the discovery of streptomycin and subsequent development of effective anti-tuberculosis therapy, the role of nutrients, whether macro or micronutrients have fallen rather by the wayside in the discussion of susceptibility and/or treatment of tuberculosis. However, the two key developments of HIV and MDR=TB in the past two decades suggest that the role of nutrition perhaps should not be so easily brushed aside. Tuberculosis, the original phthisis has found a new co-conspirator in HIV and there is much evidence of the synergistic effect of TB in HIV wasting. In addition, the development of multidrug resistance tuberculosis leads some to speculate that chronic disease may become more prevalent. Thus, it will be even more necessary to understand the role of nutrition in activation of tuberculosis. Malnutrition has been observed in patients with tuberculosis since the time of Hippocrates. Several more recent studies demonstrate patients with active pulmonary tuberculosis are malnourished as indicated by measurements of macronutrient nourishment status, i.e. reductions in visceral proteins and anthropometric indexes. Onwuballi found that patients in Harrow, England with active tuberculosis had significant reductions in BMI, triceps skinfold thickness, arm muscle circumference, serum albumin, iron, TIBC and that chemotherapy was associated with nutritional recovery and restoration of nutrition related indices. 6 Saha et al demonstrated severe weight loss, reduction of skinfold thickness, decreased albumin, prealbumin and retinol binding protein, zinc and calcium levels in tuberculosis patients in Delhi, India . Tsukaguchi et al also described malnutrition in patients with tuberculosis in Japan. 8 However, fewer studies document specific micronutrient deficiencies in patients with tuberculosis. Vitamin A deficiency was found to be common in adults with TB and HIV in Rwanda. Deficiency of vitamin A has been implicated in several studies t be associated with decreased immune function. Vitamin A deficiency has been demonstrated to increase bacterial adherence to respiratory epithelial cells. Retinoic acid can inhibit the multiplication of mycobacterium in macrophages. Requirement of vitamin A during infection increases due to increased rate of excretion and metabolism. 12 These studies suggest that vitamin A has an immunoprotective role against tuberculosis. This observation has a basis in historical fact as cod liver oil, rich in vitamins A and D was used regularly for the treatment of tuberculosis prior to the discovery of effective chemotherapy. 13 Zinc is essential in mobilizing vitamin A from the liver. In addition, zinc deficiency also affects immune defense. In animal models, it has been demonstrated to result in decreased phagocytosis, reduced numbers of circulating T cells, and reduced PPD reactivity. Zinc deficiency has been reported in patients