Soil-Transmitted Helminths: Does Nutrition Make a Difference?

Intestinal worms, commonly grouped together as soil-transmitted helminths (STHs), are the most common human parasites globally. They are estimated to infect about one quarter of the world’s population and understood to contribute to malnutrition. Less attention has been given to the impact that malnutrition might have on these infections. This chapter explores epidemiological and experimental evidence that diet and nutritional status influence the risk of exposure to infective stages and the ability of larval stages to cross tissue barriers, mature, and reproduce. It considers the impact of specific macronutrients and micronutrients on the innate and adaptive immunity to STHs and the consequences of nutrient deficiencies for STH-induced pathology. The harmful effects of STHs on host nutritional status are reviewed, together with the beneficial effects that STH-driven Th2/Treg responses have on severity of chronic nutrition-related diseases. Evidence that nutritional interventions reduce STH infection and that deworming improves nutritional status is considered. Suggestions are provided to improve both the quality of epidemiological studies and the ability to demonstrate benefits of interventions in the context of the wide set of interactions among co-existing infections, co-existing nutrient deficiencies, and the microbiome. Implications for public health interventions in resource-poor populations are considered.