Nonnative Cattle Ownership, Diet, and Child Height-for-Age: Evidence from the 2011 Uganda Demographic and Health Survey

Associations between livestock keeping, morbidity and nutritional status of children and women in low- and middle-income countries: a systematic review

Livestock keeping can positively influence the nutritional status of populations and households through increased consumption of animal-source foods (ASF) and other indirect pathways, but can also adversely affect health by increasing the risk of diseases. We conducted a systematic review synthesising the current state of knowledge on the associations among livestock keeping, infectious disease and the nutritional status of children under 5 years and women of reproductive age in low- and lower-middle-income countries (LMICs). A comprehensive search of 12 electronic databases and grey literature sources published from 1991 to the end of December 2020 was conducted. Investigations exploring relationships between livestock keeping and risk of infectious disease transmission and nutritional status were selected using pre-defined inclusion criteria. After screening and filtering of 34,402 unique references, 176 references were included in the final synthesis. Most (160/176, 90.1%) of the references included in the final synthesis were from sub-Saharan Africa (SSA) and Asia. About two out of every five (42%) studies reviewed showed that livestock production is associated with improved height-for-age Z scores (HAZ) and weight-for-length/height Z scores (WHZ), while close to a third (30.7%) with improved weight-for-age Z scores (WAZ). Similarly, livestock production showed a positive or neutral relationship with women's nutritional status in almost all the references that reported on the topic. Conversely, four-fifths (66/81, 79.5%) of the references reporting on infection and morbidity outcomes indicated that livestock keeping is linked to a wide range of infectious disease outcomes, which are spread primarily through water, food and insects. In conclusion, in many LMIC settings, livestock production is associated with better nutritional outcomes but also a higher risk of disease transmission or morbidity among women and children.This review was prospectively registered on PROSPERO 2020 [CRD42020193622].

Association of Livestock Ownership and Household Dietary Quality: Results from a Cross-Sectional Survey from Rural India

Studies from India and several eastern African countries found that the impact of dairy animal ownership on household nutrition varied greatly, depending on the socio-geographic context. The purpose of this study was to examine the association between livestock ownership and household dietary quality in rural Kolar district, India. We collected data from a household survey in four study villages (n = all 195 households of the four villages) of Kolar district, applying a cross-sectional design. Kendall's rank correlation coefficient was employed to determine the correlation between milk consumption and other dietary variables. Multivariable logistic regression was used to describe the relationship between dairy animal ownership and household milk consumption. Households owning dairy animals more often had access to irrigation (58.3% vs. 25.2%) and were less often woman-headed (2.4% vs. 22.5%). Household milk consumption was significantly correlated with consumption of vegetable variety, egg, and meat (all p-values < 0.05). After adjusting for multiple confounders, the odds ratio of milk consumption between dairy animal-owning households as compared to other households was 2.11 (95% confidence interval 0.85, 5.45). While dairy animal ownership was found to be associated with improved dietary quality, larger households were in a better position to adopt dairy animals, which, in turn, might contribute to better household nutrition.

Associations between livestock ownership and lower odds of anaemia among children 6-59 months old are not mediated by animal-source food consumption in Ghana

Livestock ownership may mitigate anaemia among young children by providing access to animal-source foods (ASFs) yet exacerbate anaemia by exposing children to animal-source pathogens. This study aimed to assess the association between household livestock ownership and child anaemia and examine whether this relationship is mediated by child ASF consumption or by child morbidity and inflammation. We conducted a cross-sectional study of 470 children aged 6-59 months in Greater Accra, Ghana. Child blood samples were analysed for haemoglobin concentration, iron status biomarkers and inflammatory biomarkers. Caregivers were asked about the child's frequency of ASF consumption in the past 3 months. Livestock ownership was categorized into five typologies to distinguish households by the number and combinations of species owned. In adjusted logistic regression, children from households in Type 5, owning cattle, small livestock (goats, sheep or pigs) and poultry, had lower odds of anaemia compared with those in Type 1, owning no livestock (OR [95% CI]: 0.32 [0.14, 0.71]). Although children from households that owned poultry were more likely to consume chicken meat, and children from households with cattle were more likely to drink cow's milk, consumption of these ASFs did not mediate the observed association between livestock ownership and child anaemia. There were no associations between livestock ownership and children's symptoms of illness or inflammation. Further research is needed to understand how ownership of certain livestock species, or a greater diversity of livestock species, may be associated with the risk of child anaemia, including the role of dietary and income-based pathways.

A biocultural examination of home food production and child growth in highland Peru

OBJECTIVES

Chronic malnutrition remains a persistent global health issue. This mixed methods investigation in rural Peru examines the role of home food production (HFP) in reducing child malnutrition by testing the following hypotheses: (a) higher HFP will be associated with higher infant z-scores than those with less HFP and (b) infants with higher HFP will exhibit improved longitudinal growth outcomes across 6 months.

METHODS

Ethnographic methods include semi-structured interviews and participant observation. A household survey and anthropometric data were collected twice, from 86 infants under of 24 months old. A HFP index (HFI) was generated based on reports of animals for meat consumption, eggs, milk, and agricultural products for home consumption. Kruskal-Wallis tests were used to examine patterns of HFI and infant anthropometrics. Multivariate regressions were used to examine the relationships between HFP and infant height for age (HAZ), weight for age (WAZ), and triceps skinfold for age (TSAZ) in both rounds and 6-month change between rounds (6MΔ).

RESULTS

There were no relationships between HFI and infant z-scores in round one, however, HFI was significantly positively related to HAZ (B = 0.091, P < .039) in round two and with 6MΔ in HAZ (B = 0.09, P < .047). HFI did not predict WAZ or TSAZ in either round.

CONCLUSIONS

HFP represents an important influence of infant growth in Nuñoa, likely through nutritional improvement due to increased availability of animal-sourced foods and through contribution to household economy and maternal empowerment.

A Systematic Review Investigating the Relation Between Animal-Source Food Consumption and Stunting in Children Aged 6-60 Months in Low and Middle-Income Countries

Animal-source foods (ASFs) are a food group of interest for interventions aimed at reducing stunting and other inadequate growth measures in early childhood. The aim of this systematic review was to examine the relation between ASF consumption and stunting in children aged 6-60 mo in low- and middle-income countries (LMICs). The secondary aim was to examine the relation between ASF consumption and other indicators of growth and development (length/height, weight, head circumference, and anemia). A search of the peer-reviewed and grey literature published from January 1980 to June 2017 was conducted. Databases searched included CINAHL, Embase, Global Index Medicus, PubMed, and Web of Science. There were 14,783 records and 116 full text articles dual screened; 21 studies were included in the review and were dual evaluated for risk of bias (RoB). The relation between ASF and stunting (length- or height-for-age z-score←2) was examined in randomized-controlled trials [(RCTs), n = 3] and cross-sectional studies (n = 4) only; ASF reduced stunting in 1 RCT and was associated with reduced stunting in 1 cross-sectional study. We did not identify any longitudinal cohorts that examined this relation. The relation between ASF and secondary indicators length/height, weight, head circumference, and anemia were largely nonsignificant across study designs. The intervention/exposure, comparator, outcome measures, methods, and analyses were highly heterogeneous. Although we did not find a consistent relation between ASF consumption and our primary and secondary outcomes, this may have been a function of inconsistencies in study design. Foods in the whole diet, particularly combination dishes, are inherently difficult to assess. To quantitatively assess the relation between ASF and stunting and other indicators of growth and iron status in early childhood, future research should provide consistency in the definition and quantification of the exposure and outcomes allowing for interstudy quantitative comparisons.

Does Village Chicken-Keeping Contribute to Young Children's Diets and Growth? A Longitudinal Observational Study in Rural Tanzania

There is substantial current interest in linkages between livestock-keeping and human nutrition in resource-poor settings. These may include benefits of improved diet quality, through animal-source food consumption and nutritious food purchases using livestock-derived income, and hazards of infectious disease or environmental enteric dysfunction associated with exposure to livestock feces. Particular concerns center on free-roaming chickens, given their proximity to children in rural settings, but findings to date have been inconclusive. This longitudinal study of 503 households with a child under 24 months at enrolment was conducted in villages of Manyoni District, Tanzania between May 2014, and May 2016. Questionnaires encompassed demographic characteristics, assets, livestock ownership, chicken housing practices, maternal education, water and sanitation, and dietary diversity. Twice-monthly household visits provided information on chicken numbers, breastfeeding and child diarrhea, and anthropometry was collected six-monthly. Multivariable mixed model analyses evaluated associations between demographic, socioeconomic and livestock-associated variables and (a) maternal and child diets, (b) children’s height-for-age and (c) children’s diarrhea frequency. Alongside modest contributions of chicken-keeping to some improved dietary outcomes, this study importantly (and of substantial practical significance if confirmed) found no indication of a heightened risk of stunting or greater frequency of diarrhea being associated with chicken-keeping or the practice of keeping chickens within human dwellings overnight.

Examining the association between livestock ownership typologies and child nutrition in the Luangwa Valley, Zambia

Objective

To investigate the association between livestock ownership and dietary diversity, animal-source food consumption, height-for-age z-score, and stunting among children living in wildlife “buffer zones” of Zambia’s Luangwa Valley using a novel livestock typology approach.

Methods

We conducted a cross-sectional study of 838 children aged 6–36 months. Households were categorized into typologies based on the types and numbers of animals owned, ranging from no livestock to large numbers of mixed livestock. We used multilevel mixed-effects linear and logistic regression to examine the association between livestock typologies and four nutrition-related outcomes of interest. Results were compared with analyses using more common binary and count measures of livestock ownership.

Results

No measure of livestock ownership was significantly associated with children’s odds of animal-source food consumption, child height-for-age z-score, or stunting odds. Livestock ownership Type 2 (having a small number of poultry) was surprisingly associated with decreased child dietary diversity (β = -0.477; p<0.01) relative to owning no livestock. Similarly, in comparison models, chicken ownership was negatively associated with dietary diversity (β = -0.320; p<0.01), but increasing numbers of chickens were positively associated with dietary diversity (β = 0.022; p<0.01). Notably, neither child dietary diversity nor animal-source food consumption was significantly associated with height, perhaps due to unusually high prevalences of morbidities.

Conclusions

Our novel typologies methodology allowed for an efficient and a more in-depth examination of the differential impact of livestock ownership patterns compared to typical binary or count measures of livestock ownership. We found that these patterns were not positively associated with child nutrition outcomes in this context. Development and conservation programs focusing on livestock must carefully consider the complex, context-specific relationship between livestock ownership and nutrition outcomes–including how livestock are utilized by the target population–when attempting to use livestock as a means of improving child nutrition.

Environmental enteric dysfunction pathways and child stunting: A systematic review

BACKGROUND

Environmental enteric dysfunction (EED) is commonly defined as an acquired subclinical disorder of the small intestine, characterized by villous atrophy and crypt hyperplasia. EED has been proposed to underlie stunted growth among children in developing countries. A collection of biomarkers, organized into distinct domains, has been used to measure different aspects of EED. Here, we examine whether these hypothesized relationships, among EED domains and between each domain and stunting, are supported by data from recent studies.

METHODOLOGY

A systematic literature search was conducted using PubMed, MEDLINE, EMBASE, Web of Science, and CINAHL between January 1, 2010 and April 20, 2017. Information on study objective, design, population, location, biomarkers, and results were recorded, as well as qualitative and quantitative definitions of EED. Biomarkers were organized into five EED domains, and the number of studies that support or do not support relationships among domains and between each domain with stunting were summarized.

RESULTS

There was little evidence to support the pathway from intestinal permeability to microbial translocation and from microbial translocation to stunting, but stronger support existed for the link between intestinal inflammation and systemic inflammation and for intestinal inflammation and stunting. There was conflicting evidence for the pathways from intestinal damage to intestinal permeability and intestinal damage to stunting.

CONCLUSIONS

These results suggest that certain EED biomarkers may require reconsideration, particularly those most difficult to measure, such as microbial translocation and intestinal permeability. We discuss several issues with currently used biomarkers and recommend further analysis of pathogen-induced changes to the intestinal microbiota as a pathway leading to stunting.