Table 3.

Studies with increased dietary fiber through diet in type 2 diabetes mellitus patients

Ref.	Population	Methods	Outcomes
Nowotny et al[24], 2015	59 German T2DM patients, enrolled for 8 wk	Intervention was increased DF (30-50 g/d); control group: Diet composed of ≤ 10 g/d DF	Both groups showed improved glycemic control and reduced weight
Belalcazar et al[35], 2014	1.701 American T2DM patients, enrolled for 48 wk	Intensive program increasing dietary fiber and physical activity, while also promoting caloric restriction	Positive changes in glycemic control, weight reduction, and other health parameters
Ziegler et al[25], 2015	30 German T2DM patients, enrolled for 8 wk	Intervention was increased DF (30-50 g/d); control group: Diet composed of ≤ 10 g/d DF	Both groups showed improved glycemic control and reduced weight. The magnitude of reduced Hb1Ac was higher in the DF intervention group
Li et al[36], 2016	298 Chinese T2DM patients, enrolled for 4 wk	Three intervention groups: Healthy diet (total DF = 33 g); 50 g oats (total DF = 36 g); and 100 g oats (total DF = 39 g); control group: Usual care without dietary changes	All intervention groups showed improved glycemic control and reduced weight. The magnitude of reduced Hb1Ac, FG, and BMI was higher in the DF intervention groups with increased DF intake
Gomes et al[26], 2017	20 Brazilian T2DM patients, enrolled for 4 wk	Compared two interventions: High glycemic diet and low GI diet	DF intake was not different between groups; the low glycemic diet induced reduced body fat, without changes in glycemic control in this study
Kondo et al[27], 2017	28 Japanese T2DM patients, enrolled for 8 wk	Compared two interventions: High fiber diet with brown rice and diet with white rice	Total DF intake increased only in the brown rice group. No differences in weight, body fat, and blood pressure were observed between the two groups. Fasting plasma glucose levels and Hb1Ac decreased in the brown rice diet group, but there was no statistically significant difference between the two groups
Tessari and Lante[28], 2017	22 Italian T2DM patients, enrolled for 96 wk	The intervention consisted in consuming a functional bread inducing increased DF intake. The control group received a regular bread	The intervention group showed improved Hb1Ac and post-prandial glucose. Body weight was increased in the intervention group, with no significant effects on other variables
Nguyen et al[29], 2019	49 Vietnamese T2DM patients, enrolled for 2 wk	Intervention consisted in Okara intake (resulting in 6 g of DF). The control received a standard diet	Intervention resulted in increased DF intake, promoting decreased FG and body weight
Yen et al[30], 2022	84 Indonesian T2DM patients, enrolled for 12 wk	Intervention consisted in increasing vegetable intake and DF intake. Control group received no counselling	Intervention with low glycemic diet induced reductions in HbA1C and body weight, and blood pressure parameters
Jenkins et al[31], 2022	134 Canadian T2DM patients, enrolled for 144 wk	Compared two interventions: Low GI diet and high fiber diet	Both interventions resulted in increased DF intake. However, low GI diet improved HB1Ac and body weight

DF: Dietary fiber; GI: Glycemic index; Hb1Ac: Glycated hemoglobin; FG: Fasting glucose; BMI: Body mass index.