Dietary homogenization and spatial distributions of carbon, nitrogen, and sulfur isotope ratios in human hair in South Korea

Abstract

Dietary homogenization has progressed worldwide due to westernization and the globalization of food production systems. We investigated dietary heterogeneity in South Korea by examining the spatial distribution of carbon (C), nitrogen (N), and sulfur (S) isotope ratios using 264 human hair samples. Overall, variation in isotope values was small, indicating low dietary heterogeneity. We detected differences in δ13C, δ15N, and δ34S values between administrative provinces and metropolitan cities; inter-regional differences were typically < 1 ‰. Values of δ34S were significantly lower in hair samples from inland regions relative to those from coastal locations, and a similar pattern was observed in δ15N values. Understanding geographic variation in δ34S and δ15N values in human hair is useful for provenancing humans in South Korea.

Multi-isotopes in human hair: A tool to initiate cross-border collaboration in international cold-cases

“…Since the seminal work of Ehleringer et al [ 33 ], country-scale studies analyzing isotopes in human hair of residents and/or tap water have become increasingly available providing the basis to develop isoscapes in many regions of the world [ 33 , 43 – 45 , 60 – 63 ]. Efforts to harmonize isotope analyses have also facilitated the integration of data generated from different laboratories, countries and times [ 37 ].…”

“…Within countries, particularly Canada and the US, we observe a trend between δ 34 S hair values and distance to the coast. δ 34 S in North American crops should reflect the mixture of isotopically light sulfates from the soil solution, and isotopically heavy marine aerosols [ 38 , 43 , 45 , 64 , 65 ]. As food systems become more distant from the coast, bedrock sulfur or anthropogenic sources, which tend to have lower values, dominate decreasing δ 34 S values.…”

“…But even in modern societies, the δ 34 S values in resident human hair display some differences between regions [ 38 , 42 – 45 ]. For example, hair of North American residents have distinctively lower δ 34 S values than those of Asians or Europeans [ 38 , 42 – 45 ]. Bataille et al (2020) further demonstrated that, within a country, systematic and predictable δ 34 S gradients were present [ 43 ].…”

“…The mixing of these two isotopically distinct sulfur sources controls a large part of δ 34 S variations observed in ecosystems and ancient human societies with high δ 34 S values in coastal environments and progressively lower δ 34 S moving inland [39][40][41]. In modern times, however, the supermarket human diet mixes products from multiple distant locations and sources, complicating the interpretation of δ 34 S values [38,[42][43][44][45]. But even in modern societies, the δ 34 S values in resident human hair display some differences between regions [38,[42][43][44][45].…”

“…In modern times, however, the supermarket human diet mixes products from multiple distant locations and sources, complicating the interpretation of δ 34 S values [38,[42][43][44][45]. But even in modern societies, the δ 34 S values in resident human hair display some differences between regions [38,[42][43][44][45]. For example, hair of North American residents have distinctively lower δ 34 S values than those of Asians or Europeans [38,[42][43][44][45].…”