Association between sex inequality in animal protein intake and economic development in the Papua New Guinea highlands: The carbon and nitrogen isotopic composition of scalp hair and fingernail

Objectives: People in the Papua New Guinea Highlands consume sweet potatoes as their dietary staple; consumption of animal protein is limited. In such societies with marginal protein intake, the intra-household allocation of animal protein in terms of sex or age is of importance. The objective of this study was to investigate how the allocation pattern of protein-rich foods by sex and age is associated with economic development in the Papua New Guinea Highlands. Methods: The carbon and nitrogen isotopic compositions of fingernails, collected in 1995 in two areas (Tari and Port Moresby [the national capital where Tari migrants resided]), and of scalp hair, collected in 2007, 2012, and 2013 in three areas of different degree of economic development (Levani, Tari, and Goroka) were analyzed. Results: Analysis of fingernail samples showed that delta N-15 was lower in rural communities than in the urban migrant community, while a sex difference in delta N-15 (higher in males than in females) was found in the former but not in the latter community. Age was not associated with either delta N-15 or delta C-13 values. The analysis of scalp hair samples showed that delta N-15 values were lowest in Levani, the least developed area. Furthermore, there were statistically significant sex differences in delta N-15 values in Levani but not in Tari and Goroka. Age was not associated with either delta N-15 or delta C-13 values. Discussion: The sex inequality in animal protein consumption seems to have decreased as the communities in the Papua New Guinea Highlands have experienced economic development. (C) 2015 Wiley Periodicals, Inc.