Dual Behavioral—Physiological Buffering of Mothers' Milk Facilitates Drought Adaptability of Pastoralists and Agropastoralists in Northern Kenya

Background
Mothers physiologically buffer key milk nutrient content against nutritional stress. How this is nested in upstream behavioral buffering is not well understood.

Objectives
The study explored whether pastoralists and agropastoralists' economic or other behavioral coping strategies against droughts, such as livestock sales and child fosterage, influence maternal risk for malnutrition or milk nutrient content.

Methods
Using data from 221 breastfeeding mothers in drought-stricken northern Kenya, we estimated generalized structural equation models to evaluate pathways linking behavioral coping variables to maternal malnutrition—underweight, vitamin A deficiency (VAD), and folate deficiency (hyperhomocysteinemia)—and to milk energy, retinol, and folate content directly or mediated by maternal malnutrition. Predictors of interest included land size, proportion of cattle/goat herds sold, children fostered/adopted out, and children living at home. Akaike Information Criterion guided model fit assessment.

Results
Land size was positively associated with maternal underweight and VAD. Child fosterage and cattle sold were inversely associated with underweight, while child fosterage and goats/sheep sold were positively associated with hyperhomocysteinemia. Children living at home were inversely associated with VAD, particularly with larger land size, and positively associated with milk retinol. Milk folate was positively associated with hyperhomocysteinemia.

Conclusions
Behavioral buffering strategies, such as fostering out children, offer incomplete protection against maternal malnutrition. The lack of effects of investigated behavioral buffering strategies on milk variables suggests physiological buffering closes the gap left by incomplete behavioral buffering. Dual behavioral-physiological buffering facilitates the drought adaptability of agropastoralists, yet heavy reliance on physiological buffering for micronutrients suggests high maternal cost.