Martin Melanie A, Garcia Geni, Kaplan Hillard S, Gurven Michael D
University of California Santa Barbara, Department of Anthropology, Santa Barbara, CA 93106-3210, USA.
University of New Mexico, Department of Anthropology, Albuquerque, NM 87131, USA.
Soc Sci Med. 2016 Dec;170:9-17. doi: 10.1016/j.socscimed.2016.10.003. Epub 2016 Oct 6.
Six months of exclusive breastfeeding (EBF) is considered optimal for infant health, though globally most infants begin complementary feeding (CF) earlier-including among populations that practice prolonged breastfeeding. Two frameworks for understanding patterns of early CF emerge in the literature. In the first, maternal and infant needs trade-off, as "maternal-centric" factors-related to time and energy demands, reproductive investment, cultural influences, and structural barriers- favor supplanting breastfeeding with earlier and increased CF. A second framework considers that "infant-centric" factors-related to infant energetic needs-favor CF before six months to supplement breastfeeding. We apply these two frameworks in examining early CF among the Tsimane-a high-fertility, high-mortality, forager-horticulturalist population residing in the Bolivian Amazon. Data were collected from a mixed-longitudinal sample of 161 Tsimane mother-infant pairs from August 2012-April 2013. Tsimane mothers generally reported introducing CF because of perceived infant needs. However, CF is introduced with continued intensive breastfeeding, and generally coupled with premastication. Risks of earlier CF relative to the minimum hazard (estimated at 5 births) were elevated for lower and higher parity mothers, but were significantly greater only after 9 births. Seventeen percent of mothers reported introducing CF because of low milk supply. Introducing CF because of low milk was most common from 0 to 3 months of age and among higher parity mothers, which may reflect physiological constraints. Maternal reproductive trade-offs and perceived infant needs may help explain the low prevalence of EBF to six months among other populations in which breastfeeding is not structurally or culturally constrained.
六个月的纯母乳喂养（EBF）被认为对婴儿健康最为理想，尽管在全球范围内，大多数婴儿更早开始添加辅食（CF），包括那些长期坚持母乳喂养的人群。文献中出现了两种理解早期添加辅食模式的框架。第一种是母婴需求的权衡，因为与时间和精力需求、生殖投入、文化影响以及结构障碍相关的“以母亲为中心”的因素，倾向于用更早和更多的辅食来取代母乳喂养。第二个框架认为，与婴儿能量需求相关的“以婴儿为中心”的因素，倾向于在六个月前添加辅食以补充母乳喂养。我们运用这两个框架来研究齐玛内人的早期辅食添加情况。齐玛内人是居住在玻利维亚亚马逊地区的高生育率、高死亡率的觅食-园艺人群。数据收集于2012年8月至2013年4月期间对161对齐玛内母婴对的混合纵向样本。齐玛内母亲普遍报告称，添加辅食是因为察觉到婴儿的需求。然而，添加辅食是在持续密集母乳喂养的情况下进行的，并且通常伴随着预咀嚼。相对于最低风险（估计为5次生育），低生育和高生育母亲早期添加辅食的风险有所升高，但只有在生育9次之后才显著更高。17%的母亲报告称因为乳汁供应不足而添加辅食。因乳汁不足而添加辅食在0至3个月大的婴儿以及高生育母亲中最为常见，这可能反映了生理限制。母亲的生殖权衡和察觉到的婴儿需求，可能有助于解释在母乳喂养在结构或文化上没有限制的其他人群中，纯母乳喂养到六个月的比例较低的原因。
