A test of the optimal iron hypothesis among breastfeeding Ariaal mothers in northern Kenya

2019

American J Hum Biol

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Objectives This study explored differing levels of macronutrients in breast milk in relation to maternal anemia and hemoglobin. Methods Archived milk specimens and data from a cross‐sectional sample of 208 breastfeeding mothers in northern Kenya, originally collected in 2006, were analyzed; data included milk fat, maternal hemoglobin concentration, and anemia status (anemia defined as hemoglobin <12 g/dL). Total protein and lactose were measured and energy was calculated. To explore the association between milk outcomes (fat, protein, lactose, and energy) and anemia, regression models were constructed with and without adjustment for maternal age, parity, and time (days) postpartum. The same models were constructed using hemoglobin as a continuous predictor in lieu of dichotomous anemia to explore the role of hemoglobin levels and anemia severity in predicting milk outcomes. Results The group comparison indicated significantly higher milk protein and lower milk fat for anemic mothers relative to nonanemic counterparts. After adjustment for maternal age, parity, and time postpartum, maternal anemia was associated with significantly higher milk protein (P = 0.001) and significantly lower milk fat (P = 0.025). Hemoglobin had a significant inverse relationship with milk protein (P = 0.017) and a marginally significant positive relationship with milk fat (P = 0.060) after adjusting for the maternal variables. Neither anemia nor hemoglobin was significant in predicting lactose or milk energy. Conclusions Maternal anemia and hemoglobin concentration may be associated with complex changes in milk macronutrients. Future research should clarify the impact of maternal anemia on a range of breast milk components while accounting for other maternal characteristics.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Variation in breast milk macronutrient contents by maternal anemia and hemoglobin concentration in northern Kenya

Corbitt

Ruvalcaba

2019

American J Hum Biol

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“…Low hemoglobin levels (<12 g/dl) defined anemia (Nestel, ). Elevated DBS TfR (>5 mg/L) defined iron deficiency (Fujita & Wander, ; Wander, Shell‐Duncan, & McDade, ). IDA was defined as anemia in presence of iron deficiency.…”

Section: Methodsmentioning

confidence: 99%

“…NIDA was defined as anemia in absence of iron deficiency. Elevated inflammation (probably indicative of acute infection) was identified with elevated blood serum CRP (>5 mg/L; Brindle, Fujita, Shofer, & O'Connor, ; Freedman, ; Fujita & Wander, ; Nakagomi, Freedman, & Geczy, ).…”

Section: Methodsmentioning

confidence: 99%

“…The same for anemia include BMI, age, parity, breastfeeding status, and inflammation/infectious disease (Alene & Mohamed Dohe, ; Antelman et al, ;Bodnar, Scanlon, Freedman, Siega‐Riz, & Cogswell, ; Semba et al, ). These variables except milk volume were available from our previous research (Fujita, ; Fujita et al, , , ; Fujita, Brindle, Lo, Castro, & Cameroamortegui, ; Fujita & Wander, ; Stone & Fujita, ) and utilized as covariates to adjust for their effects on milk characteristics.…”

Section: Methodsmentioning

confidence: 99%

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Buffered or impaired: Maternal anemia, inflammation and breast milk macronutrients in northern Kenya

American J Phys Anthropol

Ruvalcaba

Wander

et al. 2018

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Background: Maternal anemia has adverse consequences for the mother-infant dyad. To evaluate whether and how milk nutrient content may change in ways that could "buffer" infants against the conditions underlying maternal anemia, this study assessed associations between milk macronutrients and maternal iron-deficiency anemia (IDA), non-iron-deficiency anemia (NIDA), and inflammation.Methods: A secondary analysis of cross-sectional data and milk from northern Kenya was conducted (n = 204). The combination of hemoglobin and transferrin receptor defined IDA/NIDA. Elevated serum C-reactive protein defined acute inflammation. The effects of IDA, NIDA, and inflammation on milk macronutrients were evaluated in regression models.Results: IDA (β = 0.077, p = .022) and NIDA (β = 0.083, p = .100) predicted higher total protein (ln). IDA (β = −0.293, p = .002), NIDA (β = −0.313, p = .047), and inflammation (β = −0.269, p = .007) each predicted lower fat (ln); however, anemia accompanying inflammation predicted higher fat (β = 0.655, p = .007 for IDA and β = 0.468, p = .092 for NIDA). NIDA predicted higher lactose (β = 1.020, p = .003).Conclusions: Milk macronutrient content both increases and decreases in the presence of maternal anemia and inflammation, suggesting a more complicated and dynamic change than simple impairment of nutrient delivery during maternal stress. Maternal fat delivery to milk may be impaired under anemia. Mothers may buffer infant nutrition against adverse conditions or poor maternal health by elevating milk protein (mothers with IDA/NIDA), lactose (mothers with NIDA), or fat (mothers with anemia and inflammation). This study demonstrates the foundational importance of maternal micronutrient health and inflammation or infection for advancing the ecological understanding of human milk nutrient variation.

Characterizing the extent human milk folate is buffered against maternal malnutrition and infection in drought‐stricken northern Kenya

American Journal of Biological Anthropology

Wander

Tran

et al. 2022

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Objectives: Folate is an essential nutrient fundamental to human growth and development. Human milk maintains high folate content across the maternal folate status range, suggesting buffering of milk folate with prioritized delivery to milk at the expense of maternal depletion. We investigated whether and how the extent of this buffering may diminish under prolonged nutritional and/or disease stress, while taking into consideration infants' varying vulnerability to malnutrition-related morbidity/ mortality. Methods:A cross-sectional study analyzed milk specimens from northern Kenyan mothers (n = 203), surveyed during a historic drought and ensuing food shortage.Multiple regression models for folate receptor-α (FOLR1) in milk were constructed.Predictors included maternal underweight (BMI < 18.5), iron-deficiency anemia (hemoglobin <12 g/dl and dried-blood-spot transferrin receptor >5 mg/L), folate deficiency (hyperhomocysteinemia, homocysteine >12 or 14 μmol/L), inflammation (serum C-reactive protein >5 mg/L), infant age and sex, and mother-infant interactions.Results: In adjusted models, milk FOLR1 was unassociated with maternal underweight, iron-deficiency anemia and inflammation. FOLR1 was positively associated with maternal folate deficiency, and inversely associated with infant age. There was interaction between infant age and maternal underweight, and between infant sex and maternal folate deficiency, predicting complex changes in FOLR1.Conclusions: Our results suggest that mothers buffer milk folate against their own nutritional stress even during a prolonged drought; however, the extent of this buffering may vary with infant age, and, among folate-deficient mothers, with infant sex. Future research is needed to better understand this variability in maternal buffering of milk folate and how it relates to folate status in nursing infants.