The carbon isotope ratio of alanine is a biomarker of added sugar and sugar-sweetened beverage intakes: a pooled analysis of 4 studies
Year: 2025
Type: article
Abstract: BACKGROUND: The alanine carbon isotope ratio (CIR) biomarker was positively associated with added sugar (AS) and sugar-sweetened beverage (SSB) intakes in multiple studies from the United States. Association strengths varied, and Ala CIR also correlated with protein source in certain studies. OBJECTIVES: This study examined Ala CIR associations with AS and SSB intakes and animal protein ratio (APR; animal protein/total protein), and adjustment for APR, by pooling data from 4 previous studies. METHODS: We pooled diet and biomarker data from 4 studies (n = 346). These included a cross-sectional study of Yup'ik Alaska Native adults (n = 62), a 12-wk randomized controlled feeding study in males (n = 32), a 2-wk habitual intake controlled feeding study in postmenopausal females (n = 153), and a 15-d habitual intake controlled feeding study of adults (n = 99). We estimated correlations between amino acid CIRs and diet and performed multivariable regression of Ala CIR on standardized intake variables to determine simultaneous associations with AS (g/d) or SSBs (servings/d) and APR. We included study by intake interactions to allow for heterogeneity among studies. We then performed models where leucine (Leu) CIR was included to adjust for APR. RESULTS: There were positive correlations between Ala CIR and AS intake (r = 0.54; 95% CI: 0.46, 0.61), log-SSB intake (r = 0.63; 95% CI: 0.56, 0.69), and APR (r = 0.32; 95% CI: 0.22, 0.41). Study-specific slopes for the relationship between Ala CIR and AS or SSB intake were similar in models with and without adjustment for APR. Across studies, slopes ranged from 0.34 (95% CI: 0.08, 0.61) to 1.75 (95% CI: 1.29, 2.20) for AS intake in models with APR and from 0.35 (95% CI: 0.01, 0.68) to 1.11 (95% CI: 0.81, 1.40) for SSB intake in models with APR. Replacing APR with Leu CIR resulted in similar slopes between Ala CIR and AS/SSB intake. CONCLUSIONS: The Ala CIR is a robust biomarker of AS/SSB intake. Potential associations with APR can be adjusted for using a simultaneously measured biomarker. The DBD study was registered at clinicaltrials.gov as NCT01237093 and the NPAAS, an ancillary study of the Women's Health Initiative, at clinicaltrials.gov as NCT00000611.
Institutions: University of Alaska Fairbanks, Kaiser Permanente Washington Health Research Institute, Fred Hutch Cancer Center, Arizona State University, Sheba Medical Center, Oregon Health & Science University, University of Iowa, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases
Language: English
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $5,200
Funders: U.S. Department of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, National Cancer Institute, National Institute of General Medical Sciences, National Institute of Diabetes and Digestive and Kidney Diseases, National Center for Research Resources
Awards: Molecular Stable Isotope Profiles of Dietary Exposure, G1610933967, G1876869970, G2859671241, Investigating Obesity and Chronic Disease-Related Risk Factors of Alaska Natives, Genetics of Obesity in Yup'ik Eskimos, G554960330, G571830633, G5777902738, G6069943922, G6238440229, G6374953548, G6894818919, G7159829730, G7821233859, G8566225511, G872477227, G8836210513, Nutrition Obesity Research Center, Cancer Center Support Grant
OpenAlex ID: W4414798471