comparison of two calorie-reduced diets of different carbohydrate and fiber contents and a simple dietary advice aimed to modify carbohydrate intake on glycemic control and inflammatory markers in type 2 diabetes: a randomized trial

Objectives: the aim of this study was to compare the effect of a simple dietary advice with two energy-restricted diets with different carbohydrate and fiber contents on anthropometric, biochemical, and inflammatory markers over an 8-wk intervention period in individuals with diabetes. methods: forty-seven patients with type 2 diabetes (31 women and 16 men; age: 52.9 ± 8.0 years, body mass index: 29.5 ± 4.9 kg.m^-2) completed an 8-wk randomized intervention trial that compared a simple dietary advice aimed to modulate carbohydrate intake (n= 13) with the two calorie-restricted (cr) diets (25% caloric restriction from total energy requirements) differing with regard to carbohydrate and fiber content, one with higher fiber (crhf) containing 55% energy from carbohydrate plus a tablespoon of psyllium powder (n = 18) and the other with lower carbohydrate (crlc) containing 40% energy from carbohydrate plus placebo powder (n= 16). weight, plasma concentrations of glucose, insulin, lipids, interleukin-6 (il-6), and tumor necrosis factor alpha (tnf-α) were determined at baseline and after 8 weeks. results: the mean change of body weight and plasma lipids were not different between the groups. fasting plasma insulin and the homeostasis model assessment of insulin resistance (homa-ir) were significantly lower in the crhf group (changes from baseline values in simple advice, crhf, and crlc were 1.3 ± 1.9, -1.0 ± 1.2, and 0.3 ± 3.1 µil/ml for insulin and 0.5 ± 0.7, -0.3 ± 0.6, and 0.2 ± 0.9 for homa-ir, respectively). the levels of il-6 significantly decreased in the crhf and crlc groups (changes from baseline values in simple advice, crhf, and crlc were 7.5 ± 6.8, -1.2 ± 4.7, and -4.2 ± 5.6 pg/ml, respectively). tnf-α levels were significantly lower only in the crhf compared to the advice group (p < 0.05). conclusions: our results suggest that in comparison with simple advice to modify carbohydrate intake, a calorie-restricted, moderate carbohydrate diet supplemented with psyllium has better effects on plasma insulin and pro-inflammatory cytokines in patients with type 2 diabetes.