Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.
Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Am J Clin Nutr. 2020 Dec 10;112(6):1558-1565. doi: 10.1093/ajcn/nqaa241.
Advanced glycation end products (AGEs) promote adverse health effects and may contribute to the multi-system functional decline observed in aging. Diet is a major source of AGEs, and foods high in protein may increase circulating AGE concentrations. However, epidemiological evidence that high-protein diets increase AGEs is lacking.
We examined whether dietary protein intake was associated with serum concentrations of the major AGE carboxymethyl-lysine (CML) and the soluble receptor for AGEs (sRAGE) in 2439 participants from the Health, Aging, and Body Composition study (mean age, 73.6 ± 2.9 y; 52% female; 37% black).
CML and sRAGE were measured by ELISA, and the CML/sRAGE ratio was calculated. Protein intake was estimated using an interviewer-administered FFQ and categorized based on current recommendations for older adults: <0.8 g/kg/d (n = 1077), 0.8 to <1.2 g/kg/d (n = 922), and ≥1.2 g/kg/d (n = 440). Associations between protein intake and AGE-RAGE biomarkers were examined using linear regression models adjusted for demographics, height, lifestyle behaviors, prevalent disease, cognitive function, inflammation, and other dietary factors.
CML concentrations were higher in individuals with higher total protein intake (adjusted least squares mean ± SE: <0.8 g/kg/d, 829 ± 17 ng/ml; 0.8 to <1.2 g/kg/d, 860 ± 15 ng/ml; ≥1.2 g/kg/d, 919 ± 23 ng/ml; P for trend = 0.001), as were sRAGE concentrations (<0.8 g/kg/d, 1412 ± 34 pg/ml; 0.8 to <1.2 g/kg/d, 1479 ± 31 pg/ml; ≥1.2 g/kg/d, 1574 ± 47 pg/ml; P for trend < 0.0001). Every 0.1 g/kg/d increment in total protein intake was associated with a 13.3 ± 3.0 ng/ml increment in CML and a 22.1 ± 6.0 pg/ml increment in sRAGE (P < 0.0001 for both). Higher CML and sRAGE concentrations were also associated with higher intakes of both animal and vegetable protein (all P values ≤ 0.01). There were no significant associations with the CML/sRAGE ratio.
Higher dietary protein intake was associated with higher CML and sRAGE concentrations in older adults; however, the CML/sRAGE ratio remained similar across groups.
晚期糖基化终产物（AGEs）会对健康产生不良影响，并可能导致衰老过程中观察到的多系统功能下降。饮食是 AGEs 的主要来源，高蛋白食物可能会增加循环 AGE 浓度。然而，尚无高蛋白质饮食会增加 AGEs 的流行病学证据。
我们研究了 2439 名来自健康、衰老和身体成分研究（平均年龄 73.6±2.9 岁；52%为女性；37%为黑人）参与者的膳食蛋白质摄入量与血清中主要 AGE 羧甲基赖氨酸（CML）和可溶性 AGE 受体（sRAGE）浓度之间的关系。
通过 ELISA 测定 CML 和 sRAGE，并计算 CML/sRAGE 比值。通过访谈者管理的 FFQ 估计蛋白质摄入量，并根据老年人的现行建议进行分类：<0.8 g/kg/d（n=1077）、0.8 至<1.2 g/kg/d（n=922）和≥1.2 g/kg/d（n=440）。使用线性回归模型调整人口统计学、身高、生活方式行为、现患疾病、认知功能、炎症和其他饮食因素后，研究蛋白质摄入量与 AGE-RAGE 生物标志物之间的关联。
总蛋白摄入量较高的个体 CML 浓度较高（调整后的最小二乘均数±SE：<0.8 g/kg/d，829±17 ng/ml；0.8 至<1.2 g/kg/d，860±15 ng/ml；≥1.2 g/kg/d，919±23 ng/ml；P 趋势=0.001），sRAGE 浓度也较高（<0.8 g/kg/d，1412±34 pg/ml；0.8 至<1.2 g/kg/d，1479±31 pg/ml；≥1.2 g/kg/d，1574±47 pg/ml；P 趋势<0.0001）。总蛋白摄入量每增加 0.1 g/kg/d，CML 增加 13.3±3.0 ng/ml，sRAGE 增加 22.1±6.0 pg/ml（均 P<0.0001）。较高的 CML 和 sRAGE 浓度也与动物蛋白和植物蛋白的摄入量较高有关（所有 P 值均≤0.01）。CML/sRAGE 比值与蛋白质摄入量之间没有显著关联。
较高的膳食蛋白质摄入量与老年人的 CML 和 sRAGE 浓度较高有关；然而，各组之间的 CML/sRAGE 比值相似。
