ArticleThe American journal of clinical nutrition2022
An evaluation of the serum carbon isotope ratio as a candidate predictive biomarker of the dietary animal protein ratio (animal protein/total protein) in a 15-day controlled feeding study of US adults.
Article in The American journal of clinical nutrition, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.
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Who cites it
11 citing papers in PubMed.
- Responsiveness of the Serum Carbon Isotope Ratio to Dietary Added Sugar Reduction in a Randomized Controlled Trial among Youth with Steatotic Liver Disease.The Journal of nutrition · 2025Trial
- Carbon Isotope Ratios of Plasma and RBC Fatty Acids Identify Meat Consumers in a 12-Week Inpatient Feeding Study of 32 Men.The Journal of nutrition · 2023Trial
- Urine Stable Isotope Ratios Are Associated with Proportional Intakes of Animal Protein and Added Sugars in a 15-Day Controlled Feeding Study.The Journal of nutrition · 2025Article
- Carbon stable isotope values in hair are associated with added sugar intake in adults but not young children: a cross-sectional study.The American journal of clinical nutrition · 2025Observational
- Associations of Food Group Intakes with Serum Carbon Isotope Ratio Values in Youth: Results from 2 Prospective Pediatric Cohort Studies.The Journal of nutrition · 2025Article
- Reply to JCY Louie.The American journal of clinical nutrition · 2024Article
- The Carbon Isotope Ratio as an Objective Biomarker of Added Sugar Intake: A Scoping Review of Current Evidence in Human Nutrition.Advances in nutrition (Bethesda, Md.) · 2024Article
- The carbon isotope ratio of breath is elevated by short-term and long-term added sugar and animal protein intake in a controlled feeding study.The American journal of clinical nutrition · 2024Article
- Discerning animal-sourced food in diet using isotope analysis of human scalp hair and fingernails.European journal of nutrition · 2024Article
- Comparison of Total Body Vitamin A Stores Using Individual versus PopulationThe Journal of nutrition · 2023Article
- Evaluating a Model of Added Sugar Intake Based on Amino Acid Carbon Isotope Ratios in a Controlled Feeding Study of U.S. Adults.Nutrients · 2022Article
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Authors and funding
10 authors.
Funding
Abstract
backgroundThe serum natural abundance carbon isotope ratio (CIR) was recently identified as a candidate biomarker of animal protein intake in postmenopausal women. Such a biomarker would help clarify the relation between dietary protein source (plant or animal) and chronic disease risk.
objectivesWe aimed to evaluate the performance of the serum CIR as a biomarker of dietary protein source in a controlled feeding study of men and women of diverse age and BMI.
methodsWe conducted a 15-d feeding study of 100 adults (age: 18-70 y, 55% women) in Phoenix, AZ. Participants were provided individualized diets that approximated habitual food intakes. Serum was collected at the end of the feeding period for biomarker measurements.
resultsMedian [IQR] animal protein intake was 67 g/d [55-88 g/d], which was 64% of total protein. The serum CIR was positively correlated with animal protein and inversely correlated with plant protein intake, leading to a strong correlation (r2 = 0.76) with the dietary animal protein ratio (APR; animal/total protein). Regressing serum CIR on the APR, serum nitrogen isotope ratio (NIR), gender, age, and body weight generated an R2 of 0.78. Following the measurement error model for predictive biomarkers, the resulting regression equation was then inverted to develop a calibrated biomarker equation for APR. Added sugars ratio (added/total sugars intake) and corn intakes also influenced the serum CIR but to a much lesser degree than the APR; variations in these intakes had only small effects on biomarker-estimated APR.
conclusionsBased on our findings in this US cohort of mixed sex and age, we propose the serum CIR alongside NIR as a predictive dietary biomarker of the APR. We anticipate using this biomarker to generate calibrated estimates based on self-reported intake and ultimately to obtain more precise disease risk estimates according to dietary protein source.
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