Distinguishing vegan-, vegetarian-, and omnivorous diets by hair isotopic analysis

Abstract

Dietary risks contribute heavily to disability-adjusted life years (DALYs), being more important than hypertension, obesity, or smoking. To measure dietary exposure remains a challenge in nutrition research. The aim of the present study was to test the hypothesis that isotope ratios of 15N and 13C in human hair could distinguish between subjects adhering to different habitual diets. 20 male and 29 female subjects average 31 years old (range 19-53), with stable dietary habits volunteered. Diets were vegan, vegetarian and omnivorous. Hair samples were processed on an elemental analyser coupled to isotope-ratio mass spectrometry. δ15N differed between vegan, vegetarian and omnivorous diets, p<0.05 for all. δ13C differed between vegan and omnivorous diets, p<0.05, but neither of these diets were separated from the vegetarian diet. Elemental Analysis of δ13C and especially δ15N with isotope ratio mass spectrometry seems to be a promising, non-invasive and objective way to distinguish groups of subjects on different habitual diets, at least if n=>10.