Habitual intake of dietary methylglyoxal is associated with less low-grade inflammation: the Maastricht Study

BACKGROUND: Dicarbonyls are major reactive precursors of advanced glycation endproducts (AGEs). Dicarbonyls are formed endogenously, but also during food processing. Circulating dicarbonyls and AGEs are associated with inflammation and microvascular complications of diabetes, but for dicarbonyls from the diet these associations are currently unknown.OBJECTIVE: To examine the associations of dietary intake of dicarbonyls with low-grade inflammation and microvascular function.DESIGN: In 2792 participants (60 ± 8 years, 50% men, 26% type 2 diabetes) of the population-based cohort The Maastricht Study, we estimated the habitual intake of the dicarbonyls methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG) by linking Food Frequency Questionnaires to our food composition database of the MGO, GO, and 3-DG content of > 200 foods. Low-grade inflammation was assessed by six plasma biomarkers, compiled in a z-score. Microvascular function was assessed by a z-score of four plasma biomarkers, as flicker light-induced dilation and diameters in retinal micro vessels, as heat-induced skin hyperemic response, and as urinary albumin excretion. Cross-sectional associations of dietary dicarbonyls with low-grade inflammation and with microvascular function were investigated using linear regression adjusting for age, sex, potential confounders related to cardio-metabolic risk factors, lifestyle and dietary factors.RESULTS: Fully adjusted analyses revealed that higher intake of MGO was associated with a lower z-score for inflammation (std. β (95%CI) = -0.05 (-0.09, -0.01)) with strongest inverse associations for hsCRP and TNF-α (both -0.05 (-0.10, -0.01)). In contrast, higher dietary MGO intake was associated with impaired retinal venular dilation after full adjustment (std. β (95%CI) = -0.07 (-0.12, -0.01)), but not with the other features of microvascular function. GO and 3-DG intakes were not consistently associated with any of the outcomes.CONCLUSION: Higher habitual intake of MGO was associated with less low-grade inflammation. This novel, presumably beneficial, association is the first observation between MGO intake and health outcomes in humans, and warrants further investigation.