The double-edged sword of keeping livestock: balancing nutritional benefits with disease risks in poor nations
The Paper of the Month for April is from Nutrition Research Reviews (NRR) and is entitled 'Associations between livestock keeping, morbidity and nutritional status of children and women in low- and middle-income countries: a systematic review' by Taddese Alemu Zerfu, Giang Nguyen, Alan J. Duncan, Isabelle Baltenweck, Fiona Brown, Lora L. Iannotti and Geraldine McNeill.
In many low- and lower-middle-income countries, particularly in Sub-Saharan Africa (SSA), where mixed crop-livestock farming is widely practiced, livestock keeping provides income, food, nutrition and other benefits for the rural poor. The nutritional benefits of livestock keeping are particularly important since malnutrition continues to cause nearly half of annual global child deaths, and can have lasting effects on the physical growth and cognitive development of millions of surviving children. However, the relationship between livestock keeping, human nutrition and the health of most vulnerable population groups—under-five children and women of reproductive age—has remained a complex problem in many LMICs. This problem prompted us to work together and synthesise global evidence to assess the role of livestock keeping on the health and nutritional status of children and women in LMICs.
Our study synthesised data from 176 papers after screening and critically reviewing information from 12 electronic databases that produced a total of 34,402 unique references and grey literature sources published between 1991 and the end of 2020. Based on the systematic analysis of the papers, we found that nearly two out of every five (42%) of the papers reviewed showed that livestock production is associated with improved height-for-age Z score (indicator of chronic malnutrition). Our analysis also showed that weight-for-length/height Z score (an indicator of acute malnutrition) improved through livestock production. Similarly, close to a third (30.7%) of the papers reviewed showed that weight-for-age Z scores (a direct indicator of both chronic and acute malnutrition) of children improved through livestock production of families. Livestock production has also showed a positive or neutral relationship with women’s nutritional status in almost all the reported papers. However, close to four-fifths (79.5%) of the papers reporting on infection and morbidity outcomes also indicated that livestock keeping is linked to a wide range of infectious disease outcomes, which are spread primarily through water, food, and insects.
These findings strengthen the rationale of promoting a ‘One Health’ approach to livestock keeping. One Health aims to reconcile human health, livestock health and environmental health. In this case this means reducing unintended health consequences for women and young children by appropriate household sanitation practices and veterinary care. Our results underline the fact that in many LMICs, livestock production is associated with better nutritional outcomes but also poses a higher risk of disease transmission or morbidity among women and children. It is important for policymakers and public health officials to consider both the benefits and risks of livestock production in their efforts to improve the health and nutrition of these populations.
Taddese Alemu Zerfu.