The Association of Nε-Carboxymethyllysine With Polyunsaturated and Saturated Fatty Acids in Healthy Individuals

Red blood cell (RBC) fatty acid status is used as a biomarker of dietary intake of fats; however, there is still a paucity of evidence regarding individual fatty acids and modulation of endogenous advanced glycation end product (AGE) levels. Due to membrane polyunsaturated fatty acid (PUFA) being a well-known target for peroxidation, we hypothesized that cellular PUFAs are positively associated with circulatory N-epsilon-carboxymethyllysine (CML) that is also influenced by glyoxal levels in healthy cohorts. To test this, we investigated the association between RBC fatty acids and circulatory AGE biomarkers in healthy individuals. The results showed a negative association between saturated fatty acids (SFA) and CML, and stepwise multivariate regression analysis indicated that stearic acid was negatively associated with CML levels (beta = -0.200, p = .008) after adjusting for age, body mass index (BMI), and gender. In addition, stearic acid:palmitic acid ratio was also negatively correlated with plasma concentrations of CML (r(p) = -.191, p = .012) and glucose (r(p) = -.288, p = .0001). PUFAs showed a positive association with CML levels, particularly docosapentaenoic acid, gamma-linolenic acid, arachidonic acid, and docosadienoic acid. However, these associations were not evident after the multiple regression analysis adjusted for age, BMI, and gender. A strong negative correlation (r(p) = -.98, p < .0001) between total PUFA and total SFA was observed. Furthermore, the SFA:PUFA ratio was inversely correlated with CML (r(p) = -.227, p < .003). Overall, this study indicates that different fats and their combinations may influence the formation of AGEs and that carefully controlled interventions are required to further test this hypothesis.

Automated summary

The study found a negative association between saturated fatty acids and a blood biomarker of AGE, while unsaturated fatty acids showed a positive association with it. However, these associations weakened after adjusting for age, BMI, and gender.