Tsutaya Takumi, Yoneda Minoru
Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8562, Japan.
Am J Phys Anthropol. 2015 Feb;156 Suppl 59:2-21. doi: 10.1002/ajpa.22657. Epub 2014 Nov 19.
Biogeochemical methods using stable isotopes and trace elements have been increasingly developed and applied to reconstruct modern and ancient breastfeeding and weaning practices of mammals, including humans, because they offer direct proxies for the dietary intake of subadults. Carbon, nitrogen, and oxygen isotopes have been used to evaluate breast milk lipid, protein, and water intake, respectively. Carbon and sulfur isotopes have been used to estimate the content of weaning foods. The elemental concentrations of Sr and Ba in subadult tissues differ because of the dietary change during the weaning process. For analyses, various tissues have been used, such as hair, nail, blood, and feces for modern mammals and bone and teeth for ancient ones. Of these, trace element analysis of tooth enamel offers a good opportunity for the reconstruction of breastfeeding and weaning practices of the more distant past at finer resolution, although further understanding of the metabolism of trace elements is necessary. There are various tissue- and element-specific advantages and disadvantages, and a combination of different proxies can illuminate practices from various viewpoints. Finally, applying the geochemical reconstruction of breastfeeding and weaning practices to human ecology, primatology, and paleoanthropology is important; basic studies of the underlying physiological mechanisms and technical improvements in the analyses will further highlight avenues for future research.
利用稳定同位素和微量元素的生物地球化学方法已得到越来越多的发展，并被应用于重建包括人类在内的哺乳动物现代和古代的母乳喂养及断奶模式，因为它们能为亚成体的饮食摄入提供直接的替代指标。碳、氮和氧同位素已分别用于评估母乳中的脂质、蛋白质和水分摄入。碳和硫同位素已用于估算断奶食物的含量。由于断奶过程中的饮食变化，亚成体组织中锶和钡的元素浓度有所不同。在分析中，已使用了各种组织，如现代哺乳动物的毛发、指甲、血液和粪便，以及古代哺乳动物的骨骼和牙齿。其中，牙釉质的微量元素分析为以更高分辨率重建更久远过去的母乳喂养和断奶模式提供了一个很好的机会，尽管有必要进一步了解微量元素的代谢情况。不同的组织和元素有各自的优缺点，结合使用不同的替代指标可以从多个角度阐明相关模式。最后，将母乳喂养和断奶模式的地球化学重建应用于人类生态学、灵长类学和古人类学很重要；对潜在生理机制的基础研究以及分析技术的改进将进一步突出未来研究的方向。
