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NTDs and Nutrition

A Competition for Nutrients

By Chad MacArthur, Helen Keller International 

There are numerous ways in which neglected tropical diseases and nutrition negatively impact one another. NTDs comprise 17 parasitic, viral and bacterial diseases, which compete for the nutrients of the host to survive, grow and reproduce.  This competition for nutrients naturally imposes a significant cost on the host, who may already be vulnerable. The infected person’s nutritional status may also be compromised by the body’s response to the infection, which may include increased metabolic rate and consequently greater depletion of nutrients and energy; loss of appetite and thus reduced intake and damage to tissue leading to malabsorption of nutrients.  Although initially these responses are protective, chronic or repeated infections can cause the person to become undernourished.  In turn, undernutrition makes a person more susceptible to infections and can increase the severity of disease. Since most people affected by NTDs are from marginalized communities where the diet is already low in critical nutrients, infection exacerbates their already poor nutritional status.  NTDs are known for their debilitating nature and for causing physical disabilities.  These disabilities also reduce an individual’s economic productivity as well as that of other family members, who must assist the afflicted person. These burdens often leave the family food-insecure, further undermining nutritional status. Together these consequences can send individuals and entire communities into a downward spiral.

Impacts on Maternal and Child Health

The consequences of NTDs, particularly soil-transmitted helminthes and schistosomiasis, on maternal and child health are especially grave.  The link between STH infection and anemia is well-established, as is the increased risk of maternal mortality among women with anemia. Though anemia can be due to multiple causes and its control requires a package of interventions, treating NTDs comprises an essential element of integrated control strategies. It is estimated that in sub-Saharan Africa, over 37 million women of reproductive age (6.9 million pregnant women) are infected with hookworm, and approximately 40 million women of reproductive age with schistosomiasis. It is further estimated that 57% of pregnant women in Africa and 48% in Southeast Asia suffer from anemia, leaving them at great risk.  Women with severe anemia are 3.5 times more likely to die during or after childbirth. Maternal anemia also leads to low-birth weight of the newborn and infant anemia, each of which in turn, increases the risk of infant mortality.  

The nutritional consequences of NTDs are various. One of the most important is the stunted growth and underweight in children under 5 years of age, particularly due to soil-transmitted helminthes. Both stunting and anemia also impair cognitive development of those infected, putting those children at an educational disadvantage at school and socio-economic disadvantage as they grow up. Evidence also indicates an association between ascariasis (roundworm infection) and low vitamin A status.  Vitamin A deficiency is well-documented as a cause of under-five mortality, while undernutrition is estimated to be a cause of 45% of all child deaths.

Implications for NTD Programs

Preventive chemotherapy can be provided for many NTDs (lymphatic filariasis, onchocerciasis, schistosomiasis, STH and trachoma), with medicines available at a low cost or donated and delivery is being successfully scaled up. However, these efforts do not comprehensively address the problems caused by these infections nor do they adequately address the problems resulting from undernutrition. The reduction of NTD infection does not necessarily equal health. Therefore, funders and implementers of mass drug administration programs for NTDs should consider integrating nutrition interventions with the other essential public health strategies such as hygiene and sanitation to facilitate full recovery, restore the health of individuals, families and communities and protect the population against future infections.