Dietary advanced glycation end-product restriction for the attenuation of insulin resistance, oxidative stress and endothelial dysfunction: a systematic review.

The benefits of advanced glycation end-product (AGE)-restricted diets in humans are unclear. This review aimed to determine the effect of dietary AGE restriction on the inflammatory profiles of healthy adults and adults with diabetes or renal failure. Eight computer databases were searched for controlled feeding trials published in English between January 1997 and December 2012. Human trials were included if at least one group received an AGE-restricted dietary intervention. A total of 12 trials reporting on 289 participants were included in the review. Five trials (42%) were of high methodological quality. Meta-analysis of two long-term (16 week) trials provided evidence favoring an AGE-restricted diet for the reduction of 8-isoprostanes (standardized mean difference 0.9; 95% confidence interval (CI): 0.3-1.5) and tumor necrosis factor-α (1.3; 95% CI: 0.6-1.9) in healthy adults. Intermediate-term dietary AGE restriction in adults with chronic renal failure reduced serum VCAM-1 (0.9; 95% CI: 0.1-1.7). Individual trials provided some evidence that long-term dietary AGE restriction reduces HOMA-IR (1.4; 95% CI: 0.3-2.6) and AGE-modified low-density lipoprotein (2.7; 95% CI: 1.6-3.9) in adults with type 2 diabetes. Generalisability is limited, as 75% of studies were of less than 6 weeks duration and more than half were of low methodological quality. Evidence quality ranged from low to very low, limiting the conclusions that can be drawn from this review. There is currently insufficient evidence to recommend dietary AGE restriction for the alleviation of the proinflammatory milieu in healthy individuals and patients with diabetes or renal failure. Additional long-term high-quality RCTs with larger sample sizes measuring patient-important outcomes are required to strengthen the evidence supporting the effects of AGE-restricted diets.