Contribution of dietary advanced glycation end products (AGE) to circulating AGE: Role of dietary fat

The purpose of this pilot study was to determine whether macronutrient content (low-fat v. high-fat diet) influences an indicator of advanced glycation end products (AGE), N ^I carboxymethyl-lysine (CML), in the context of a 1-d, high-AGE diet. The effect of the diets on inflammatory markers was also assessed. A total of nineteen overweight and obese adults (nine men and ten women) without known disease were recruited to participate in a crossover challenge of a high-fat, high-AGE (HFHA) and low-fat, high-AGE (LFHA) diet. In each phase patients had fasting blood drawn, followed by consumption of a high-fat or low-fat breakfast test meal, then three postprandial blood draws at 1, 2 and 3 h after consuming the test meal. After consuming high-AGE meals for the remainder of the day, participants returned the next day for a follow-up analysis. A different pattern in the 3-h post-meal CML and soluble receptor for AGE response to the two diets was observed (P=0·01 and 0·05, respectively). No change in serum CML was observed following consumption of a LFHA breakfast (535 (25th-75th percentile 451-790) to 495 (25th-75th percentile 391-682) ng/ml; P=0·36), whereas a rise in CML occurred after the HFHA breakfast (463 (25th-75th percentile 428-664) to 578 (25th-75th percentile 474-865) ng/ml; P=0·05). High sensitivity C-reactive protein and high molecular weight adiponectin were not affected by either diet. These findings suggest that dietary CML may not be as important in influencing serum CML as other dietary factors. In addition, acute exposure to dietary CML may not influence inflammation in adults without diabetes or kidney disease. This is contrary to previous findings.