Dietary Heterogeneity among Western Industrialized Countries Reflected in the Stable Isotope Ratios of Human Hair

Abstract

Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization). Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ13C values (−22.7 to −18.3‰), and significantly higher δ15N (7.8 to 10.3‰) and δ34S (4.8 to 8.3‰) values than samples from the USA (δ13C: −21.9 to −15.0‰, δ15N: 6.7 to 9.9‰, δ34S: −1.2 to 9.9‰). Within Europe, we detected differences in hair δ13C and δ34S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.

Laboratory and field methods for stable isotope analysis in human biology

“…Hair is the most commonly studied tissue for SIA in field studies among living humans (Bender et al, 2015;Bol et al, 2007;Bol and Pflieger, 2002;de Luca et al, 2012;Fuller et al, 2006;Hatch et al, 2006;Mekota et al, 2006;O'Connell and Hedges, 1999;Petzke et al, 2006;Petzke et al, 2010;Romek et al, 2013;Valenzuela et al, 2012;Valenzuela et al, 2011). One of the primary advantages of using hair in isotopic studies is the longitudinal record of isotopic data it contains.…”

Global spatial distributions of nitrogen and carbon stable isotope ratios of modern human hair

“…Humans living in northern Europe have the lowest δ 13 C values worldwide, as has been reported previously. [17] In general, the δ 13 C values are lower in Europe than in the rest of the world. The highest δ 13 [20,21] as well as unpublished data.…”

“…[20,21] The differences in isotope ratios between hair and nail are attributed to differing amino acid compositions as well as to potentially different amino acid turnover in hair follicles and the nail matrix, although the exact mechanisms remain unclear. [20] Because most of the published carbon and [4] Portugal, Spain -19.9 ±0.6 (49) (1,3); [4,17] Bulgaria, Moldova, Romania* -20.0 ±0.5 (36) (2,3); [4] Czech Rep., Hungary, Slovakia* -20.1 ±0.8 (70) [4,29] France -20.3 ±0.6 (≥61) + (3); [4,17,26,36] Italy incl. Malta* -20.3 ±0.5 (48) [4,17] Russia, Ukraine -20.3 ±0.6 (≥58) (2,3); [4,36] Belgium, Luxembourg -20.4 ±0.7 (≥19) + (2); [4,17,26,36] Germany -20.5 ±0.6 (478) (1,3); [4,6,7,9,12,13,17,36] Greece incl.…”

“…[20] Because most of the published carbon and [4] Portugal, Spain -19.9 ±0.6 (49) (1,3); [4,17] Bulgaria, Moldova, Romania* -20.0 ±0.5 (36) (2,3); [4] Czech Rep., Hungary, Slovakia* -20.1 ±0.8 (70) [4,29] France -20.3 ±0.6 (≥61) + (3); [4,17,26,36] Italy incl. Malta* -20.3 ±0.5 (48) [4,17] Russia, Ukraine -20.3 ±0.6 (≥58) (2,3); [4,36] Belgium, Luxembourg -20.4 ±0.7 (≥19) + (2); [4,17,26,36] Germany -20.5 ±0.6 (478) (1,3); [4,6,7,9,12,13,17,36] Greece incl. Cyprus -20.6 ±0.5 (10) (3); [4,17] Netherlands -20.6 ±0.4 (≥18) (3); [4,17,36,37] Austria, Switzerland -20.7 ±0.9 (58) (2,3); [4,10,17] Denmark -20.8 ±0.4…”

Assigning stranded bottlenose dolphins to source stocks using stable isotope ratios following the Deepwater Horizon oil spill

“…Samples were processed and analyzed as detailed by Valenzuela et al (2012). In summary, skin samples were freeze-dried overnight or up to 24 h (FreeZone Freeze Dry System), lipid-extracted with a 2:1 chloroform:methanol mixture for 48 h using a Soxhlet extractor, and then cut into fragments.…”