From Local Farms to Supermarket Foods: The Story of the Homogenization of the Argentine Diet Told by the Isotope Ratios of Modern Teeth.

Objectives: Nutritional changes over the last century, driven by globalization, hypermarketization, and malnutrition, are global in scale. Large countries in the Global South might be resilient to dietary homogenization due to their natural diversity of regions and ecosystems, which might have prevented the adoption of supermarket diets. Argentina has a wide array of ecosystems and historically different subsistence diets dependent on regional characteristics. We analyzed the spatiotemporal variation of stable isotope values in Argentina using modern teeth to test for regional dietary patterns and its consistence over time.

Materials and methods: We collected teeth from voluntary donors born between 1940 and 2010, from 72 locations across Argentina. A total of 119 teeth were analyzed for the markers δ¹³C_dentine, δ¹³C_enamel, δ¹⁵N, and δ³⁴S. A reconstruction of isotopic niches was performed to estimate dietary patterns across different regions and time periods.

Results: This study is the first to analyze changes in modern dietary patterns in Argentina using isotopic data measured in contemporary teeth. We showed latitudinal, longitudinal, and temporal differences in isotopic values, reflecting the variation in available resources within the country. Changes in the diet were observed over time, including declining δ¹⁵N values, a reduction in δ³⁴S range, and a trend toward homogenization of δ¹³C_enamel values. Conversely, δ¹³C_dentine values remained constant over time, maintaining latitudinal patterns and regional differences across regions.

Discussion: This study increases our understanding of modern population dietary patterns both spatially and over the last 70 years. Our findings suggest that the Argentine population has shifted toward a supermarket diet in recent years.