Role of Nutritional Deficiencies in Tropical Sprue

Abstract

A detailed dietary history covering the period before onset of symptoms was obtained from eighty-six patients with tropical sprue and from ten patients with megaloblastic anemia of pregnancy. In our patients with sprue, a comparison of the mean intake of important nutrients with the recommended dietary allowances of the National Research Council indicated suboptimal amounts of calories, total and complete protein, vitamins A and C, riboflavin, niacin and iron. The diets of patients with megaloblastic anemia of pregnancy were considerably lower in most constituents than those of female patients with sprue. A comparison of the diets of our patients with minimum requirements demonstrated only a moderate deficiency of calories in our patients with sprue, whereas the diets of patients with megaloblastic anemia of pregnancy were deficient in all vitamins studied by us as well as calcium. The apparently contradictory clinical observations on the role of dietary deficiencies in the pathogenesis of tropical sprue are considered and a hypothesis resolving them is proposed: It is suggested that sprue is a manifestation of a genetically transmitted defect of metabolism which impairs intestinal absorption by affecting the energy-producing enzyme systems in the cells of the intestinal mucosa. In a population which chronically exists on the verge of undernutrition, the delicate nutritional balance of genetically susceptible persons can be easily upset by a worsening of the diet or any of a variety of unfavorable environmental factors which increase metabolic demands. This intensifies the inborn disturbance of intestinal absorption and aggravates the dietary deficiencies, especially of protein and of B vitamins, which eventually leads to profound malnutrition and other manifestations of sprue. Patients with megaloblastic anemia of pregnancy who had greater dietary deficiencies than the patients with sprue, as well as an important form of metabolic stress, but in whom sprue failed to develop, appear to confirm the importance of a genetic defect in the etiology of this disease.