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

Introduction: Contemporary dietary and nutritional transitions are commonplace, but difficult to study directly. In Brazil, and Latin America, this generalized process, leading to current obesity and malnutrition problems, started more than four decades ago. Although body weight and food availability are used to measure changes, not much information on food consumption and nutrition exist. Stable isotope analysis allows for the study of modern individual diets because it reflects the proportional contribution of different foods, general dietary patterns, and the effect of metabolism. Furthermore, when samples from tissues reflecting different time points are used, it allows for the assessment of individual transitions.

Objectives: To explore intra-person isotopic variation for the first time in the Southern Hemisphere for modern humans, and examine the nutritional transition reported for Brazil in the past four decades.

Materials: Stable carbon and nitrogen isotope values from 68 C-dated bone samples (vertebra, occipital, parietal, femur) from 17 individuals born in 1963, from three cemeteries.

Results: Data reflect chronologically ordered high intra-individual δN variation tracking the dietary and nutrition transition over the last few decades, while no relationship between δC values and time was found. Vertebrae, reflecting diets from the mid 2000s, showed lower δN values than other bones reflecting the mid 1980s and early 1990s.

Discussion: We show how different bones capture nutritional transitions over the lifespan of modern individuals. Nitrogen isotope values were lower in recent tissues as a consequence of the changes in the agri-food industry and worldwide consumption patterns that have intensified in Latin America in the last decades.