The carbon isotope ratio of RBC alanine is a biomarker of sugar‐sweetened beverage (SSB) intake

• Published in: The FASEB Journal
• Main Authors: OˈBrien, Diane Marie, Choy, Kyungcheol, Nash, Sarah
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: eskimo*; Yup'ik
• Online Access: http://dx.doi.org/10.1096/fasebj.26.1_supplement.131.2

We are developing biomarkers of sugar‐sweetened beverage (SSB) intake for application in a Yup'ik Eskimo population, to detect associations with chronic disease risk. The naturally‐occurring carbon isotope ratio of human serum and RBC has been proposed as a biomarker of SSB intake, based on the elevated carbon isotope ratio of corn syrup and cane sugar. However, the marker's utility is diminished by a concurrent relationship with meat from corn‐fed animals. Here we evaluated the association of SSB intake and the carbon isotope ratio of individual amino acids in RBC, to investigate whether one might provide a biomarker that was more specific to SSB intake. The carbon isotope ratio of alanine was strongly (r = 0.70) associated with SSB intake but not associated with intake of corn‐fed market meat. Alanine can be readily synthesized in cells from pyruvate, which derives from glucose. We suggest that this synthetic pathway allows the capture of carbon from dietary sugars in tissue proteins, such as RBC, providing a stable biomarker of intake. This study was funded by a Center of Biomedical Research Excellence grant from the NIH NCRR (P20 RR16430‐10) and NIH NIDDK R01DK07442