Agricultural interventions to improve nutritional status of children

Summary of review¹

A summary of a recent systematic review on the effectiveness of agricultural interventions that aim to improve nutritional status of children has recently been published. In order to be included in the review, studies had to investigate agricultural interventions with the explicit goal of improving the nutritional status of children. Interventions included were bio-fortification, home-gardening, aquaculture, small scale fisheries, poultry development, animal husbandry and dairy development. The review only included studies from the published and unpublished literature that were produced after 1990, were written in English, were conducted in a middle or low income country, reported an effect on at least one of the selected outcome indicators, and used a credible counterfactual method.

Twenty three studies were selected for the review. The reviewers investigated the effects along all the main steps of the causal chain running from the agricultural intervention to the final goal of reducing under-nutrition, specifically participation in the programme by poor people, household income, composition of the diet, iron and vitamin A intakes, and prevalence of stunting, wasting and underweight.

The studies reported no information on participation rates or characteristics of programme participants. The interventions reviewed had a positive effect on production and consumption of the agricultural goods promoted, but reviewers found no evidence of a change in total household income and little evidence of a change in the overall diet of poor people. No evidence was found of an effect on iron intake but there was some evidence of a positive effect on the absorption of vitamin A. Very little evidence existed of an effect on the prevalence of undernutrition. Of eight studies reporting undernutrition rates, only one found a statistically significant effect on prevalence of stunting, whereas three studies found a positive effect on prevalence of underweight and two found a positive effect on wasting.

Many of the studies reviewed had methodological weaknesses. Post hoc power calculations showed that most studies were unlikely to find an effect on undernutrition rates if present, because of the small sample sizes used. Furthermore, factors such as health environment and cultural practices may have affected the impact of the agricultural interventions reviewed independently of their efficacy.

¹Masset E et al (2012). Effectiveness of agricultural interventions that aim to improve nutritional status of children: systematic review. BMJ February 2012, volume 433, pp 16