Olsen Karyn C, White Christine D, Longstaffe Fred J, von Heyking Kristin, McGlynn George, Grupe Gisela, Rühli Frank J
Department of Anthropology, The University of Western Ontario, London, ON, Canada.
Am J Phys Anthropol. 2014 Apr;153(4):598-604. doi: 10.1002/ajpa.22459. Epub 2013 Dec 30.
Paleodiet research traditionally interprets differences in collagen isotopic compositions (δ(13) C, δ(15) N) as indicators of dietary distinction even though physiological processes likely play some role in creating variation. This research investigates the degree to which bone collagen δ(13) C and δ(15) N values normally vary within the skeleton and examines the influence of several diseases common to ancient populations on these isotopic compositions. The samples derive from two medieval German cemeteries and one Swiss reference collection and include examples of metabolic disease (rickets/osteomalacia), degenerative joint disease (osteoarthritis), trauma (fracture), infection (osteomyelitis), and inflammation (periostitis). A separate subset of visibly nonpathological skeletal elements from the German collections established normal intraindividual variation. For each disease type, tests compared bone lesion samples to those near and distant to the lesions sites. Results show that normal (nonpathological) skeletons exhibit limited intraskeletal variation in carbon- and nitrogen-isotope ratios, suggesting that sampling of distinct elements is appropriate for paleodiet studies. In contrast, individuals with osteomyelitis, healed fractures, and osteoarthritis exhibit significant intraskeletal differences in isotope values, depending on whether one is comparing lesions to near or to distant sites. Skeletons with periostitis result in significant intraskeletal differences in nitrogen isotope values only, while those with rickets/osteomalacia do not exhibit significant intraskeletal differences. Based on these results, we suggest that paleodiet researchers avoid sampling collagen at or close to lesion sites because the isotope values may be reflecting both altered metabolic processes and differences in diet relative to others in the population.
古饮食研究传统上把胶原蛋白同位素组成（δ(13)C、δ(15)N）的差异解释为饮食差异的指标，尽管生理过程可能在造成这种变化中也起到了一定作用。本研究调查了骨骼中骨胶原蛋白δ(13)C和δ(15)N值正常情况下的变化程度，并研究了古代人群中几种常见疾病对这些同位素组成的影响。样本来自两个中世纪德国墓地和一个瑞士参考样本集，包括代谢性疾病（佝偻病/骨软化症）、退行性关节疾病（骨关节炎）、创伤（骨折）、感染（骨髓炎）和炎症（骨膜炎）的例子。从德国样本集中选取的明显无病理特征的骨骼元素的一个单独子集确定了个体内部的正常变化。对于每种疾病类型，测试将骨病变样本与病变部位附近和远处的样本进行了比较。结果表明，正常（无病理特征）骨骼在碳和氮同位素比率方面的骨骼内变化有限，这表明对不同元素进行采样适用于古饮食研究。相比之下，患有骨髓炎、愈合骨折和骨关节炎的个体在同位素值上表现出显著的骨骼内差异，这取决于比较的是病变部位与附近还是远处的部位。患有骨膜炎的骨骼仅在氮同位素值上导致显著的骨骼内差异，而患有佝偻病/骨软化症的骨骼则未表现出显著的骨骼内差异。基于这些结果，我们建议古饮食研究人员避免在病变部位或其附近采样胶原蛋白，因为同位素值可能既反映了代谢过程的改变，也反映了与人群中其他个体相比饮食上的差异。
