Correspondence between human diet, body composition and stable isotopic composition of hair and breath in Fijian villagers

Abstract

The main aim of this work was to describe the relationship between diet, and hair and breath isotopic composition. From one Fijian rural village, hair and breath samples were procured from 20 women. Physical anthropometrics were made, and hair 13C/12C and 15N/14N and breath 13C/12C were measured. Individual diet diaries were kept for two of the four preceding weeks, and isotopic compositions of items which accounted for most of the diet were measured. Individual average diets were analysed for macronutrient and energy content and conform to reasonable nutritional expectation. Characteristics of the diet are described in terms of protein and energy, their patterning with respect to different clusters of food items and their relationship to individuals’ anthropometry. Breath CO2 is depleted in 13C by 1–2‰ on average with respect to the total diet. Hair was enriched on average by 4.1‰ in nitrogen and 4.5‰ in carbon with respect to the total diet. There was insufficient population variation in hair isotopic composition to establish individual hair–diet isotopic differences. The definite relationship that we establish in this work, between dietary and tissue isotopic values for a human community, provides a basis for determining and validating dietary regimes more generally within non-industrial, non-global-‘supermarket’ economies.