Evaluation of the Association Between Carrageenan and Systemic Inflammation: Results From the National Health and Nutrition Examination Survey

This study investigated the association between carrageenan (CGN) in protein supplement beverages and C-reactive protein (CRP), a marker of systemic inflammation, in a nationally-representative survey of US adults. The analysis included 922 adults who reported use of protein supplement beverages and had CRP measurements in the National Health and Nutrition Examination Survey (1999-2010, 2015-2023). In the primary analysis, users of liquid protein beverages (proxy for CGN exposure) were compared with users of beverages prepared with powders (proxy for unexposed). A secondary analysis compared participants using protein beverages with and without CGN (n = 622). Multivariable linear regression evaluated associations between CGN and log-transformed CRP. Overall, use of CGN-containing protein supplements was not significantly associated with CRP (primary ratio:1.07, 95%CI:0.74-1.55; secondary:0.98, 95%CI:0.66-1.47). However, some differences by health status (p-interaction = 0.04) were observed, with some suggestions of association among participants reporting poorer health (primary:1.91, 95%CI:0.92-3.97; secondary:3.14, 95%CI:1.43-6.91). No significant interactions were found for age, gender, obesity, or time, despite some suggestive evidence of associations in younger adults and females. Use of CGN-containing protein supplement beverages was not associated with higher CRP overall, but hypothesis-generating data warrant future larger studies to evaluate the role of CGN on inflammation in specific population subgroups.