Age of introduction to animal source foods and its association with child growth indices in low-income informal settlements of Nairobi, Kenya

Objectives: Animal-sourced foods (ASFs) contain essential nutrients for human growth, maintenance, and repair. This study quantifies the relationship between the age of ASF introduction and later child growth indices in low-income Kenya informal settlements.

Methods: A two-stage sampling method selected seven wards with high ASF value chain activity in Nairobi, Kenya, and randomly sampled 304 mother and child (6-59 months) dyads from low-income households in September to October 2019. Mothers completed a cross-sectional survey that assessed breastfeeding duration, exclusive breastfeeding for six months, and age of introduction of animal milk, poultry, red meat, and eggs. Child anthropometrics were collected. Linear regressions examined associations between breastfeeding and complementary feeding practices with child growth indices, adjusting for maternal age, education, household size, and income, stratified by child age in years.

Results: Over 99% of children were breastfed (duration mean±SD = 19±6 months), and 35% were still breastfeeding at the time of assessment. Exclusive breastfeeding lasted 4±3 months, with 58% of children exclusively breastfed for six months. Breastfeeding duration was not associated with child growth indices. Mothers introduced animal milk at 6±3 months, poultry and red meat at 8±5 months, and eggs at 9±5 months. Later introduction to ASFs (in months) was associated with higher weight-for-age z-scores among children aged 24-36 months: animal milk β=0.07 [95% CI=0.01,0.12]; poultry β=0.04 [0.003,0.08]; red meat β=0.04 [0.002,0.08]; eggs β=0.05 [0.001,0.09]. Age of introduction to ASFs was not associated with weight-for-age in any other age group or with length-for-age, weight-for-length, or BMI z-scores across all age groups.

Conclusions: In Nairobi, Kenya’s informal settlements, we found that most children were breastfed, with over half exclusively breastfed for the first six months. Mothers typically introduced animal milk first, followed by meat and eggs. Results suggest that in these low-income settlements where average age of introduction to ASFs is in line with current feeding recommendations, age of introduction to ASF was not significantly associated with child growth indices.