The purpose of this study was to compare effects of a moderate carbohydrate diet supplemented with psyllium with those of a lower carbohydrate diet supplemented with placebo powder on glycemic control in patients with type 2 diabetes (T2D). In an open randomized controlled trial, 37 patients with T2D with body mass index (BMI) 25-35 kg/m2 received either a low-energy, moderate carbohydrate diet plus 7 grams of psyllium powder (MoCyllium group) or a low-energy, lower carbohydrate diet plus placebo powder (LoCarb group) for 2 weeks. Fasting and 2-hour postprandial plasma glucose, insulin, and tumor necrosis factor-α (TNF-α) as well as the homeostasis model assessment of insulin resistance (HOMA-IR) were determined at the beginning and end of the 2-week period. Postprandial samples were obtained after ingestion of a standardized breakfast meal in both groups. Body weight change did not differ between the two groups. There was no significant intervention effect on fasting plasma glucose. Fasting plasma insulin and TNF-α significantly decreased from baseline in the MoCyllium group (p = .01). The differences of absolute change of insulin and TNF-α between the groups were statistically significant (p = .002 and p = .017, respectively). Insulin sensitivity, evaluated by HOMA-IR, increased significantly in the MoCyllium group (p = .016), and comparison of absolute change between the groups showed a trend toward statistical significance. No statistical differences were detected among postprandial glucose, insulin, and TNF-α concentrations. The finding supports the concept that in diabetic patients with cultural preferences to a higher carbohydrate diet, an increase in soluble fiber intake should be encouraged.
Keywords: TNF-α; diabetes; diet; insulin; psyllium.