Glycemic control indicators changes
The magnitude of glycemic control indicators reduction seen in this study were seen in other clinical trials.
Feinglos et al., in his clinical trial noted that 3.4 g dose and 6.8 g dose of psyllium significantly lowered HbA1c and FBS [
33]. Another study concluded that, a psyllium dose of 5.1 g/day significantly reduced FBS and HbA1c [
34]. Likewise, in the current study all glycemic control indicators were significantly improved when these changes compared FBS, HbA1c, insulin and C-peptide
p < 0.001,
p < 0.001,
p < 0.001,
p = 0.001, respectively). Interestingly, these positive results were achieved due to soluble fiber effect in reducing glucose absorption about 12.2 % and as therapeutic agent for other metabolic control [
35], while regular intake of soluble fibers, particularly may have a protective role for the presence of metabolic syndrome of patients with type 2 DM [
13]. Though, psyllium as an example of viscose functional water soluble fiber which may delay intestinal transit time and leading to feel fullness [
36], retarding the entry of glucose into the bloodstream and lessening the postprandial rise in blood sugar [
37]. It may lessen insulin requirements [
38]. Soluble fiber may produce a slower and longer-lasting release and absorption of macronutrients due to increased intraluminal viscosity [
26,
39]. In the intestine, the gel-like material that formed by soluble fiber traps nutrients inside its gel and slows down considerably while passing through the digestive tract. Inside the gel, nutrients are protected from the action of digestive enzymes and less likely to reach the wall of the intestines for absorption [
40]. This lowers the sharp rise of blood sugar after meal, and improves the sensitivity of the cells to the action of insulin [
40]. In addition, Water soluble fiber thickens the unstirred water layer covering the surface of the intestines, which make the nutrients more resistant to cross this layer and to diffuse into the body [
41]. Also, it has been reported that, soluble fiber decreased postprandial glucose and insulin responses and influenced concomitant gastrointestinal (GI) peptide responses, especially ghrelin and Peptide YY release [
39]. Another clinical trial showed that psyllium improve FBS, insulin, HOMA Index, HbA1c significantly [
42]. Another randomized crossover study, demonstrated that high intake of dietary fiber, particularly of the soluble type, improves glycemic control, decreases hyperinsulinemia and lowers plasma lipid concentrations in patients with type 2 diabetes [
43]. In addition, the use of HOMA for assessment of β-cell function and insulin sensitivity which can detect the pathophysiology in those with abnormal glucose tolerance, thus HOMA is useful analysis tool of the treatment [
44]. Consequently, recent studies among hyperglycemic individuals with no prior diagnosis of diabetes mellitus found to improve insulin sensitivity and other important metabolic controls [
45,
46,
47,
48,
49]. This is most likely due to the viscosity of soluble fibers inside the gastrointestinal tract [
29].
