1.
Differential Effects of Dietary Patterns on Advanced Glycation end Products: A Randomized Crossover Study.
Kim, Y, Keogh, JB, Deo, P, Clifton, PM
Nutrients. 2020;(6)
Abstract
Dietary advanced glycation end products (AGEs) are believed to contribute to pathogenesis of diabetes and cardiovascular disease. The objective of this study was to determine if a diet high in red and processed meat and refined grains (HMD) would elevate plasma concentrations of protein-bound AGEs compared with an energy-matched diet high in whole grain, dairy, nuts and legumes (HWD). We conducted a randomized crossover trial with two 4-week weight-stable dietary interventions in 51 participants without type 2 diabetes (15 men and 36 women aged 35.1 ± 15.6 y; body mass index (BMI), 27.7 ± 6.9 kg/m2). Plasma concentrations of protein-bound Nε-(carboxymethyl) lysine (CML), Nε-(1-carboxyethyl) lysine (CEL) and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The HMD significantly increased plasma concentrations (nmol/mL) of CEL (1.367, 0.78 vs. 1.096, 0.65; p < 0.01; n = 48) compared with the HWD. No differences in CML and MG-H1 between HMD and HWD were observed. HMD increased plasma CEL concentrations compared with HWD in individuals without type 2 diabetes.
2.
Consumption of red and processed meat and refined grains for 4weeks decreases insulin sensitivity in insulin-resistant adults: A randomized crossover study.
Kim, Y, Keogh, JB, Clifton, PM
Metabolism: clinical and experimental. 2017;:173-183
Abstract
BACKGROUND Red and processed meat and refined grains are associated with an increased risk of type 2 diabetes. Interventions are limited. We hypothesized that a diet high in red and processed meat and refined grains (HMD) would decrease insulin sensitivity compared to a diet high in whole grains, nuts, dairy and legumes with no red meat (HWD). METHODS Forty-nine subjects without diabetes [15 men and 34 women, age, 35.6±15.7 years, body mass index (BMI), 27±5.9kg/m2] underwent two 4-week weight-stable dietary interventions in a randomized crossover design. The insulin sensitivity index (ISI) was calculated from the last 30min of a continuous low-dose insulin (25mU/kg·h) and glucose (4mg/kg·min) infusion test (LDIGIT 120-150min) at the end of each diet. RESULTS The population fell into two very discrete groups: those with a very low insulin response in the LDIGIT 120-150min on HMD (Group 1<56pmol/L, n=24), and those with relatively normal insulin responses (Group 2>56pmol/L, n=25). Group 2 had significantly higher insulin concentrations [(median and interquartile range) 153, 180 for HMD vs. 123, 149pmol/L for HWD; P=0.019] and glucose concentrations [(mean±standard deviation) 7.4±1.3 for HMD vs.6.7±1.2mmol/L for HWD; P=0.05], resulting in a significantly decreased ISI [(median and interquartile range) 21.1, 34.2 for HMD vs. 31.6, 39.4 for HWD; P=0.014] compared to HWD. Log ISI after HMD was significantly correlated with BMI (r=-0.5; P=0.009), fat mass (r=-0.55; P=0.004) and self-reported activity levels (r=-0.45; P=0.024). CONCLUSIONS A dietary pattern high in red and processed meat and refined grains decreased insulin sensitivity compared to a dietary pattern high in whole grains, nuts, dairy products and legumes only in relatively insulin-resistant adults.