RATIONALE Stable isotopic analyses are increasingly used to study the diets of past and present human populations. Yet, the carbon and nitrogen isotopic data of modern human diets collected so far are biased towards Europe and North America. Here, we address this gap by reporting on the dietary isotopic signatures of six tropical African communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria) from Kenya, and Baka from Cameroon; representing four subsistence strategies: fishing, pastoralism, agriculturalism, and hunter-gatherer. METHODS We used an elemental analyser coupled in continuous-flow mode to an isotope ratio mass spectrometer to measure the carbon and nitrogen isotopic ratios of hair (n = 134) and nail (n = 80) and the carbon isotopic ratios of breath (n = 184) from these communities, as well as the carbon and nitrogen isotopic ratios of some food samples from the Kenyan communities. RESULTS We expand on the known range of δ13 C values in human hair through the hunter-gatherer Baka, with a diet based on C3 plants, and through the agriculturalist Luhya (Webuye), with a diet based on C4 plants. In addition, we found that the consumption of fish from East African lakes is difficult to detect isotopically due to the combined effects of high nitrogen isotopic ratios of plants and the low nitrogen isotopic ratios of fish. Finally, we found that some of the communities studied are markedly changing their diets through increasing sedentism and urbanisation. CONCLUSIONS Our findings contribute substantially to the understanding of the environmental, demographic, and economic dynamics that affect the dietary landscape of different tropical populations of Africa. These results highlight the importance of studying a broader sample of human populations and their diet, with a focus on their precise context - from both isotopic and more general anthropological perspectives.

中文翻译：

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来自非洲热带人群的头发，指甲和呼吸的碳和氮同位素特征。

理性的同位素分析越来越多地用于研究过去和现在人类的饮食。但是，迄今为止收集的现代人类饮食中的碳和氮同位素数据偏向欧洲和北美。在这里，我们通过报告六个热带非洲社区的饮食同位素特征来弥补这一差距：El Molo，图尔卡纳（Kerio），Luhya（Webuye），Luhya（维多利亚港）和来自肯尼亚的Luo（维多利亚港），以及来自肯尼亚的Baka喀麦隆 代表了四种生存策略：捕鱼，牧民，农业主义和猎人与采集者。方法我们将元素分析仪以连续流动模式与同位素比质谱仪耦合使用，以测量头发（n = 134）和指甲（n = 80）的碳和氮同位素比以及呼吸的碳同位素比（n = 184）来自这些社区，以及来自肯尼亚社区的一些食物样品的碳和氮同位素比。结果我们通过使用基于C3植物的饮食的猎人-采集者Baka以及通过使用基于C4植物的饮食的农业学家Luhya（Webuye）扩展了人发中δ13C值的已知范围。此外，我们发现由于高氮同位素的植物和低氮同位素的鱼的综合影响，很难从同位素上检测到东非湖泊的鱼类消费。最后，我们发现，某些研究社区通过增加久坐感和城市化而显着改变了他们的饮食。结论我们的发现对理解环境，人口统计，以及影响非洲不同热带种群饮食结构的经济动态。这些结果强调了从同位素和更一般的人类学角度出发，研究更广泛的人口样本和饮食，并关注其确切背景的重要性。