Carbon and nitrogen isotopic signatures of hair, nail, and breath from tropical African human populations

Abstract

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 δ 13 C values in human hair through the hunter-gatherer Baka, with a diet based on C 3 plants, and through the agriculturalist Luhya (Webuye), with a diet based on C 4 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 contextfrom both isotopic and more general anthropological perspectives.

Weaning and stunting affect nitrogen and carbon stable isotope natural abundances in the hair of young children

“…Last, it is also worth noting that in our study, δ 15 N and δ 13 C estimates at the plateau were lower than those previously reported by Fuller et al in adults 34 , but close to those previously reported for modern vegetarians and vegans 5,12 -suggesting a low consumption of ASF in this low-income Bangladeshi population 43 . Regarding hair δ 15 N, the adult values estimated by our δ 15 N trajectory fit are very close to those reported for a rural Kenyan population whose livelihood also relies on agriculture 44 . However, hair δ 13 C values notably differ between these two populations, due to differential consumption of foods derived from C4 plants.…”

“…However, hair δ 13 C values notably differ between these two populations, due to differential consumption of foods derived from C4 plants. Corn and millet (C4 plants) are the major cereals in the Kenyan diet 44 whereas the major staple food in Bangladesh is rice (C3) 45 .…”

Applying dental microwear texture analysis to the living: Challenges and prospects

“…Webuye are increasingly participating in market economies, consuming higher proportions of processed maize and sugar (Correia, 2018;Correia, Foley, O'Connell, Ramírez-Rozzi, & Lahr, 2019).…”

“…Dietary data from 24‐hr recalls and semiquantitative food frequency questionnaires indicate that the main staples consumed by the individuals included in this study match those described in the literature relatively well (Table 1). However, dietary data (as well as isotopic data) also detected that the Turkana (Kerio) are increasingly replacing animal products with famine relief foods, namely maize flour (reflecting their increased sedentarization), whereas the Luhya from Webuye are increasingly participating in market economies, consuming higher proportions of processed maize and sugar (Correia, 2018; Correia, Foley, O'Connell, Ramírez‐Rozzi, & Lahr, 2019).…”

“…Organization as a valid dental hygiene method (WHO, 1984). However, of relevance here, esekon is also known for being used for longer periods of time, often several times a day, primarily on the anterior teeth, and for being potentially tougher than conventional toothbrushes, all of which can impact on patterns of dental microwear rely heavily on C 4 foods (Correia et al, 2019). C 4 foods are often cereals, which are known for leaving distinct marks on teeth (Bullington, 1991;Ungar et al, 2019), although this may also depend on the manner of cereal processing rather than on the properties of the cereals themselves (Mahoney, 2006;Schmidt et al, 2015;Teaford & Lytle, 1996).…”