Guest blog post by Christopher Juan Costain with Water and Sanitation Program South Asia, World Bank
Malnutrition is not only a direct and indirect cause of infant mortality; it also causes stunting and has life-long influences on learning and IQ which will impair future earning capacity.
The challenge of overcoming malnutrition remains one of the most intractable, particularly for those of us living in India, a country that appears year after year in the Global Hunger Index, below countries emerging from conflict such as Liberia. Surprisingly, malnutrition shows much less correlation with income than might be expected - as much within India as between countries.
Much of what we read about malnutrition focuses on food security and the related issues of availability, access, and affordability. While these broad concepts do loosely include social and cultural themes, such as gender empowerment, which are seen to be highly relevant, the issue of absorption of micronutrients, and particularly the important role played by safe sanitation, is frequently overlooked or underemphasized.
Many people may also be surprised to learn that India has a similarly unfavorable ranking in terms of the percentage of people practicing open defecation (for example, 51% for India versus 45% for Liberia). This is important as several studies emphasize that sanitation and hygiene are a key determinant of a child’s nutritional status. Perhaps 50% of the consequences of under-nutrition can be attributed to poor environmental health conditions as a result of diseases such as diarrhea, tropical enteropathy, and nematode infections.
A study of two year-olds showed the probability of stunting increased by 2.5% per episode of diarrhea, and 25% of all stunting was attributable to having five or more episodes of diarrhea. Another calculation indicates that each year some 860,000 of malnutrition-related deaths of under-fives are induced by unsafe water, sanitation, and hygiene.
Tropical enteropathy (increasingly referred to as environmental enteropathy as it is not restricted to the tropics) is receiving increasing attention in the development community as it underscores that the impact of poor sanitation is not only through diarrhea, but also that fecal bacteria, ingested in large quantities by young children living in conditions of poor sanitation, cause damage to the intestinal wall, decreasing the capacity to absorb micronutrients.
The evidence for the protective effect of sanitation against diarrhea is strong, with latrine usage potentially reducing diarrhea by an average of 36%. It is also a technology that is within the reach of every village and it is admirably cost effective. The World Bank ranks hygiene promotion as the most cost-effective public health intervention ($3 per DALY averted) followed by sanitation promotion ($11 per DALY averted).
It would be simplistic to seek to solve India or the world’s malnutrition challenge solely through improved sanitation, but given the huge health impact and the modest cost, in addition to the myriad social and economic benefits to be gained through improved sanitation for all, this has to be a worthy focus for our resources and our attention and should be part of the conversation surrounding malnutrition prevention.
 UNICEF/WHO (2009): Diarrhoea: Why children are still dying and what can be done;
WHO (2008), Safer Water, Better Health – Costs, benefits and sustainability of interventions to protect and promote health;
Int J Epidemiol 2008, Checkley W, Buckley G, Gilman RH, et al, The Childhood Malnutrition and Infection Network. Multi-country analysis of the eff ects of diarrhoea on childhood stunting.;
Lancet (2009); Humphrey JH. Child undernutrition, tropical enteropathy, toilets, and handwashing.
 Scott, (2006): Well Fact Sheet- Health Influences of Improved Household Sanitation