The World Health Organization (WHO) estimates that 50 percent of child undernutrition cases are due to repeated diarrhea and intestinal infections caused by poor sanitation and hygiene conditions or lack of safe water.[i] Handwashing with soap is a critical determinant for achieving and maintaining good nutrition, and this healthy behavior plays an important part in preventing micronutrient deficiencies, stunting, wasting, and deaths.

Stunting, or low height for age, is caused by long-term insufficient nutrient intake and frequent infections in early childhood, resulting in delayed motor development, impaired cognitive function, and reduced school performance. Nearly one third of children under the age of five in low income countries are stunted.

Wasting, or low weight for height, is caused by acute insufficient nutrient intake and/or disease, and is a strong predictor of mortality among children under the age of five.

If disease-causing bacteria, viruses, or parasites on a person’s hands enter their mouth, they can travel down to the gut where they may damage the body’s ability to use nutrients from food. The likely ways that these germs can do this are by directly consuming nutrients before the body can use them[ii] and by damaging the intestinal lining (this is referred to as environmental enteropathy). Environmental enteropathy includes flattening out parts of the (villus blunting), which reduces places where nutrients can be absorbed into the body. As such, nutrients that pass through the gut but fail to be absorbed can be lost in diarrhea.[iii] These pathogens can also irritate the gut, which can damage its barrier functions, make it easier for toxins to get inside the body, and cause chronic inflammation, which can further damage the gut and use up nutrients in the process.[iv]

Diarrhea and undernutrition can become a vicious cycle.

Children are susceptible to infection by bacteria and viruses in fecal matter (poo) that cause diarrhea. When children get diarrhea, they (a) often eat less food, and (b) have a reduced ability to absorb and benefit from nutrients in the food they do eat, contributing to the development of under-nutrition. When children are undernourished, they become more susceptible to developing diarrhea when they come into contact with the bacteria and viruses in fecal matter. And so the cycle goes around again.

Handwashing breaks the vicious cycle of diarrhea and undernutrition.

Good handwashing with soap can prevent nearly half of all cases of childhood diarrhea. It is also estimated that drinking clean water and handwashing with soap can reduce the loss of nutrients through diarrhea and reducing stunting in children under the age of five by up to 15 percent,[v] [vi] giving children a better chance of maintaining good nutrition and growing up to thrive.

Given the important role of handwashing in nutrition, the Global Handwashing Partnership helped co-found the Clean, Fed & Nurtured Community of Practice which works to explore and promote the integration of WASH, nutrition, and early childhood development in the 0-3 age range. We also provide a number of resources relating to the integration of nutrition and handwashing in our resources section.


[i] World Health Organisation, Safer water, better health: Costs, benefits and sustainability of interventions to protect and promote health. 2008.

[ii] Solomons NW. Pathways to the impairment of human nutritional status by gastrointestinal pathogens. Parasitology 1993; 107:S19–35.

[iii] Solomons NW. Pathways to the impairment of human nutritional status by gastrointestinal pathogens. Parasitology 1993; 107:S19–35.

[iv] Sharp TM, Estes MK. An inside job: subversion of the host secretory pathway by intestinal pathogens. Curr Opin Infect Dis 2010; 23:464–9.

[v] Fenn, B. et al. (2012). An evaluation of an operations research project to reduce childhood stunting in a food-insecure area in Ethiopia. Public Health Nutrition, 15(9), 1746-1754.

[vi] Dangour, A. D. et al. (2013). Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children. The Cochrane Library.