Association between advanced glycation end-products and depression and anxiety scores in healthy adults

Nearly half of all Australians (42.9%) will experience a mental health disorder during their lifetime (1) . Preliminary research suggests an association between dietary and tissue advanced glycation end-products (AGEs) and mental health conditions, such as depression (2,3) . However, more research is needed to determine the extent to which poor mental health is linked with AGEs (4) . This study examined whether dietary consumption of the AGE carboxymethyl-lysine (CML), tissue accumulation of AGEs, or levels of circulating glycated haemoglobin (HbA1c) were associated with depression or anxiety. Fifty adults participated in a cross-sectional study. Depression and anxiety were assessed using the Centre for Epidemiologic Studies Depression Scale (CES-D) and Spielberger’s State-Trait Anxiety Inventory (STAI). Dietary CML intake was assessed from 3-day food records by matching food items to those in published, validated food AGE databases and adjusting for energy intake (CML/MJ). Tissue accumulation of AGEs was measured as skin autofluorescence (SAF) using an AGE Reader. HbA1c was measured in whole blood using a Capillary 3 HbA1c kit. Spearman’s rank correlations were performed to explore relationships between variables. Participants included 14 males and 36 females, aged (median (range)) 30.6 (18–72) years. Participants were predominantly healthy, with a BMI of 23.3 (18.5–31.1) kg/m 2 and energy intake of 7889 (5452–12568) kJ/day. Depression scores were 8 (0–40) out of 60. State anxiety scores were 26 (20–53) and trait anxiety scores were 33.5 (20–66) out of 80, where higher scores indicated greater symptom severity. Daily intake of CML was 0.6 (0.2–1.9) mg/MJ/day. SAF was 1.8 (1.2–3.3) arbitrary units (AU), similar to previously reported normal reference values (5) . Circulating HbA1c was 5.1% (4.4–6.2%), all within the healthy range (6) . Spearman’s correlation tests indicated no significant associations between any of the independent variables (CML/MJ, SAF, HbA1c) and any of the dependent variables (CES-D, STAI) (all p > 0.05). In this population of predominantly of healthy individuals, there was no association between dietary CML intake, tissue AGE accumulation or circulating HbA1c and increased symptom severity for depression or anxiety. The next step of this research is to investigate metabolomic markers in this population and their association with depression and anxiety. In relatively healthy people, dietary metabolites may be more sensitive to uncover whether a relationship exists between AGEs and depression and anxiety.