Many studies have been done into how nutrition and child growth (or lack of stunting) are linked. But a Viewpoint in this week's edition of The Lancet explores the importance of toilets and hand hygiene in ensuring children grow normally in the developing world, where toilets are largely absent and hand hygiene poor.
The Viewpoint, written by Dr Jean Humphrey, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA, says that improvements in this area could reduce the prevalence of tropical enteropathy, a condition in which the small intestine becomes inflamed and functions poorly due to bacterial infestation. Dr Humphrey believes poor toilet and hand hygiene is the cause of much of this problem, and hypothesises that improving these two key things could lead to substantial decreases in stunting in developing countries.
Dr Humphrey uses an analogy of chickens to illustrate her point. Controlled studies have shown that chicks in dirty conditions can grow normally if they are fed antibiotics to stave off the bacteria they are exposed to in that environment; whereas chicks in the same conditions not given antibiotics do not grow as well. In both children and chickens, biological markers of inflammation increase substantially in unhygienic conditions, indicating that both children and chickens enter a 'near-continuous state of growth-suppressing immune response', in which dietary nutrients are directed away from growth into providing energy and building materials for the immune response. The consequences on growth in children can be immense, especially in the first two years of life when growth demands are high.
Dr Humphrey says: "How can children be protected from faeces? Safe disposal of stools (ie, toilets) and handwashing with soap after faecal contact are the primary barriers to faecal-oral transmission because they prevent faeces from entering the domestic environment. Many randomised trials of handwashing have shown substantial reductions in diarrhoea, although none included the effect of these interventions on tropical enteropathy or child growth. Surprisingly, there are no published randomised trials of toilet provision on child growth or even diarrhoea."
She concludes: "I hypothesise that prevention of tropical enteropathy, which afflicts almost all children in the developing world, will be crucial to normalise child growth, and that this will not be possible without provision of toilets. Randomised controlled trials of toilet provision and handwashing promotion that include tropical enteropathy and child growth as outcomes will give valuable evidence for this premise, and might offer a solution to the intractable problem of child undernutrition."
Dr Jean Humphrey, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA T) +1 263-4-301-840 E) jhumphrey@zvitambo.co.zw
For full Viewpoint, see: http://press.thelancet.com/vpundernutrition.pdf
Journal
The Lancet