Beyond diet reconstruction: Stable isotope applications to human physiology, health, and nutrition

Abstract

Analysis of stable carbon and nitrogen isotopes from soft or mineralized tissues is a direct and widely-used technique for modeling diets. In addition to its continued role in paleodiet analysis, stable isotope analysis is now contributing to studies of physiology, disease, and nutrition in archaeological and living human populations. In humans and other animals, dietary uptake and distribution of carbon and nitrogen among mineralized and soft tissue is carried out with varying efficiency due to factors of internal biology. Human pathophysiologies may lead to pathology-influenced isotopic fractionation that can be exploited to understand not just skeletal health and diet, but physiological health and nutrition. This study reviews examples from human biology, non-human animal ecology, biomedicine, and bioarchaeology demonstrating how stable isotope analyses are usefully applied to the study of physiological adaptation and adaptability. Suggestions are made for future directions in applying stable isotope analysis to the study of nutritional stress, disease, and growth and development in living and past human populations.

Lombards on the Move – An Integrative Study of the Migration Period Cemetery at Szólád, Hungary

“…However, the dataset lacks a possible breastfeeding mother or wet nurse with such isotope data ranges. In addition, starvation or a metabolic disease may also have contributed to the unusual stable isotope ratios of the infant [70], [71].…”

The Importance of Isotopic Turnover for Understanding Key Aspects of Animal Ecology and Nutrition

“…Alternately, it is possible to assess nutritional status by its effect on the isotopic composition of tissues. Food deprivation, in particular, typically results in elevated δ 15 N values in tissues, due to the preferential retention of the heavier isotope during repeated de-and trans-amination of amino acids [117][118][119][120][121][122]. Fasting also seems to be related to changes in the δ 13 C enrichment, but the observed effects have been much less consistent, with elevated δ 13 C in chicken (Gallus gallus) hemoglobin [123] and bonobo (Pan paniscus) urine [118], but mixed results in human hair [119,122], and no effect on the muscle or liver in ross' geese (Chen rossii) [117].…”

The potential for a carbon stable isotope biomarker of dietary sugar intake

“…The pathway most used will depend upon the nitrogen balance and carbohydrate intake of the individual: states of negative nitrogen balance (i.e., low protein intake or starvation) and/or high carbohydrate intake will result in a greater proportion of nonessential amino acids derived from carbohydrates compared to states of positive nitrogen balance and/or low carbohydrate intake. 179,180 While most Americans consume adequate levels of dietary protein to remain in nitrogen balance equilibrium, 181 the continuum of carbohydrate and protein consumption may produce inter-and intra-individual differences in biomarker sensitivity to SSB intake. Thus, while RBC alanine is a promising candidate biomarker of SSB consumption, further testing in a more heterogenous population with a broad range of carbohydrate and protein intake is need to determine its applicability to the general population.…”

“…Furthermore, tissue d 15 N values may be affected by other physiological conditions, including caloric availability, total protein content of the diet, and pathological conditions such as liver disease. 180 Thus, further testing in the general U.S. population is warranted to determine the relationship between tissue d 15 N and commercial meat intake and validate the dual isotope model as a strategy for increasing the sensitivity of d 13 C-based biomarkers.…”