Intra-Individual Stable Isotope Variation Tracks Brazilian Contemporary Dietary and Nutritional Transition.

Area of Science:

• Paleonutrition
• Human dietary evolution
• Stable isotope analysis

Background:

• Dietary and nutritional transitions are significant global health challenges, particularly in Latin America, contributing to obesity and malnutrition.
• Studying these transitions directly is challenging, with limited data on food consumption and nutrition.
• Stable isotope analysis offers a method to study individual diets and transitions by examining tissue samples from different time points.

Purpose of the Study:

• To investigate intra-person isotopic variation in modern humans in the Southern Hemisphere.
• To analyze the nutritional transition in Brazil over the past four decades using stable isotope analysis.

Main Methods:

• Analysis of stable carbon and nitrogen isotope values from 68 14C-dated bone samples (vertebra, occipital, parietal, femur).
• Samples were from 17 individuals born in 1963, sourced from three cemeteries.
• Chronological analysis of isotopic variation within individuals.

Main Results:

• High intra-individual nitrogen isotope (δ15N) variation was observed, tracking dietary and nutritional changes over time.
• No significant relationship was found between carbon isotope (δ13C) values and time.
• Vertebrae (reflecting mid-2000s diets) showed lower δ15N values compared to other bones (mid-1980s/early 1990s diets).

Conclusions:

• Different bone tissues can reflect nutritional transitions throughout an individual's lifespan.
• Lower nitrogen isotope values in recent tissues are linked to shifts in the agri-food industry and global consumption patterns in Latin America.