Stable isotopes in hair reveal dietary protein sources with links to socioeconomic status and health

Abstract

Carbon and nitrogen isotope ratios in hair sampled from 65 communities across the central and intermountain regions of the United States and more intensively throughout 29 ZIP codes in the Salt Lake Valley, Utah, revealed a dietary divergence related to socioeconomic status as measured by cost of living, household income, and adjusted gross income. Corn-fed, animal-derived proteins were more common in the diets of lower socioeconomic status populations than were plant-derived proteins, with individual estimates of animal-derived protein diets as high as 75%; United States towns and cities averaged 57%. Similar patterns were seen across the socioeconomic status spectrum in the Salt Lake Valley. It is likely that corn-fed animal proteins were associated with concentrated animal-feeding operations, a common practice for industrial animal production in the United States today. Given recent studies highlighting the negative impacts of animal-derived proteins in our diets, hair carbon isotope ratios could provide an approach for scaling assessments of animal-sourced foods and health risks in communities across the United States.

A planetary health perspective on synthetic methionine

“…An isotopic analysis of hair clippings taken from a US population shows that consumption of cornfed animal protein stratify by socioeconomic status. 41 Similar trends could be present for synthetic methionine consumption. This provisional estimate could be more precisely specified through collaboration by diverse stakeholders.…”

Dietary homogenization and spatial distributions of carbon, nitrogen, and sulfur isotope ratios in human hair in South Korea

“…Canada [18,19,44] and Oceania [18,44,[46][47][48] are also illustrated (Fig 4B). The δ 13 C values of Korean hair were intermediate to those of the USA (+ Canada) [2,4,6,18,19,42,44,49,50] and EU (+ Oceania) [6,8,18,44,51,52], suggesting proportional relationships with the consumption of C3 and C4 plants and seafood. Based on both δ 13 C and δ 15 N values, male Koreans eat both C3 and C4 plants and are omnivorous.…”

“…For comparison, the USA, which mainly consumes C4 plants reflected by high δ 13 C values [18], and the European Union (EU), which mainly consumes C3 plants reflected by low δ 13 C values [4], are also shown (Fig 4B). Canada [18,19,44] and Oceania [18,44,[46][47][48] are also illustrated (Fig 4B).…”

“…Stable isotope analyses of bio-elements, including carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S), are commonly used to investigate the dietary protein sources consumed by both contemporary and past human populations [1][2][3][4]. Dietary intake patterns are recorded in body tissues such as hair, nail, bones, and teeth, which allow for the reconstruction of lifestyle attributes related to geographic origin and dietary habits [5][6][7].…”

“…The global spatial distribution of δ 13 C values in human hair is strongly related to the amount of C4 plants in human diets [18,20] and δ 15 N values are reflective of trophic level, and can thus indicate whether an individual is omnivorous or vegetarian if they consume only terrestrial foods [4]. Individuals who consume large amounts of fish and seafood are expected to have higher δ 15 N values than those who mainly eat terrestrial foods [21].…”