Abstract
Rationale: The stable carbon (δ13C) and nitrogen (δ15N) isotope composition of human bone and tissues encodes dietary information that in some circumstances can be attributed to geographical location. While there is a global dataset amounting to > 4000 samples, limited data are available for the Australasian region.
Methods: One hundred and seven nail/hair samples were detergent and solvent pretreated and analysed for δ13C and δ15N composition, sourced from individuals normally residing in southern Australia (temperate), northern Australia (seasonal tropical) and urban Papua New Guinea (tropical). Isotope values for nails were converted to hair keratin equivalent values using accepted fractionation factors. The results were compared with each other, and with the global datasets available from Europe, Asia, Africa and the Americas.
Results: The southern Australian and Papua New Guinean data exhibit a similar mean and range to each other for both δ13C and δ15N values, comparable to results for some regions of Europe and Asia. The northern Australian data extends to higher δ13C values than the other groups due to a greater component of carbon in the diet ultimately from a C4 source. Vegetarians exhibit a similar range to the omnivores in δ13C but tend to lower δ15N values.
Conclusions: Global supply chains and industrial fertilizer use have reduced the range δ13C and nitrogen δ15N values in the samples in this study, as has been the case globally. The range of values observed reflects the ability of consumers to access local produce from supermarkets or local markets. The Australasian data tend to lower δ13C values than the global average, indicating a dominance of carbon assimilated by C3 photosynthesis in the diet. While similar to some European and Asian populations, δ13C values are lower than from regions with a high reliance on carbon assimilated by C4 photosynthesis, including the Americas and parts of Africa.
Methods: One hundred and seven nail/hair samples were detergent and solvent pretreated and analysed for δ13C and δ15N composition, sourced from individuals normally residing in southern Australia (temperate), northern Australia (seasonal tropical) and urban Papua New Guinea (tropical). Isotope values for nails were converted to hair keratin equivalent values using accepted fractionation factors. The results were compared with each other, and with the global datasets available from Europe, Asia, Africa and the Americas.
Results: The southern Australian and Papua New Guinean data exhibit a similar mean and range to each other for both δ13C and δ15N values, comparable to results for some regions of Europe and Asia. The northern Australian data extends to higher δ13C values than the other groups due to a greater component of carbon in the diet ultimately from a C4 source. Vegetarians exhibit a similar range to the omnivores in δ13C but tend to lower δ15N values.
Conclusions: Global supply chains and industrial fertilizer use have reduced the range δ13C and nitrogen δ15N values in the samples in this study, as has been the case globally. The range of values observed reflects the ability of consumers to access local produce from supermarkets or local markets. The Australasian data tend to lower δ13C values than the global average, indicating a dominance of carbon assimilated by C3 photosynthesis in the diet. While similar to some European and Asian populations, δ13C values are lower than from regions with a high reliance on carbon assimilated by C4 photosynthesis, including the Americas and parts of Africa.
| Original language | English |
|---|---|
| Article number | e10058 |
| Number of pages | 7 |
| Journal | Rapid Communications in Mass Spectrometry |
| Volume | 39 |
| Issue number | 15 |
| Early online date | 2 May 2025 |
| DOIs | |
| Publication status | E-pub ahead of print - 2 May 2025 |
Keywords
- geoforensics
- diet
- palaeodiet
- keratin
- isoscape