Yajuan Xie1, Luoning Gou2, Miaomiao Peng1, Juan Zheng1, Lulu Chen3. 1. Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, 430022, China; Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China. 2. Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, 430022, China; Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China. 3. Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, 430022, China; Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China. Electronic address: cheria_chen@126.com.
Abstract
BACKGROUND & AIMS: Soluble dietary fiber is prompted as an important part of reducing blood glucose, ameliorating insulin resistance and controlling body weight. Thus, we performed this systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify and synthesize the effects of soluble fiber supplementation on glycemic control and BMI modification in adults with type 2 diabetes. METHODS: We searched MEDLINE, Embase, Web of Science, ClinicalTrials.gov, and Cochrane databases until February 13, 2020 to identify RCTs that detected the effects of soluble fiber supplementation on glycemic control in adults with type 2 diabetes. A random-effects model with the generic inverse variance method was used to analyze the pooled data. The meta-regression and subgroup analyses were conducted to identify the variables that influenced the pooled results. The robust error meta-regression model was used to conduct the dose-response test. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was undertaken to evaluate the overall quality of the evidence. RESULTS: A total of 29 RCTs (33 comparisons) involving 1517 participants were identified in this meta-analysis. Results showed that supplemental soluble dietary fiber significantly reduced glycosylated hemoglobin (HbA1c, MD -0.63%, 95% CI [-0.90, -0.37]; P < 0.00001), fasting plasma glucose (FPG, MD -0.89 mmol/L, 95% CI [-1.28, -0.51]; P < 0.00001), fasting insulin (SMD -0.48, 95% CI [-0.80, -0.17]; P = 0.003), homeostatic model assessment of insulin resistance (HOMA-IR, SMD -0.58, 95% CI [-0.86, -0.29], P < 0.0001), fructosamine (SMD -1.03, 95% CI [-1.51, -0.55]; P < 0.0001), 2-h postprandial plasma glucose (SMD -0.74, 95% CI [-1.00, -0.48]; P < 0.00001), and BMI (SMD -0.31, 95% CI [-0.61, -0.00], P = 0.05) compared with control diets in patients with type 2 diabetes. Specifically, dose-response meta-analyses presented that a daily dosage of 7.6-8.3 g was recommended. CONCLUSION: Intake of soluble fiber supplementation is effective in improving glycemic control and BMI level in type 2 diabetes and is also a convenient way to help individuals meet standard dietary fiber needs. But due to the evidence of substantial heterogeneity in most pooled estimates, further long-term and high-quality RCTs are needed.
BACKGROUND & AIMS: Soluble dietary fiber is prompted as an important part of reducing blood glucose, ameliorating insulin resistance and controlling body weight. Thus, we performed this systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify and synthesize the effects of soluble fiber supplementation on glycemic control and BMI modification in adults with type 2 diabetes. METHODS: We searched MEDLINE, Embase, Web of Science, ClinicalTrials.gov, and Cochrane databases until February 13, 2020 to identify RCTs that detected the effects of soluble fiber supplementation on glycemic control in adults with type 2 diabetes. A random-effects model with the generic inverse variance method was used to analyze the pooled data. The meta-regression and subgroup analyses were conducted to identify the variables that influenced the pooled results. The robust error meta-regression model was used to conduct the dose-response test. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was undertaken to evaluate the overall quality of the evidence. RESULTS: A total of 29 RCTs (33 comparisons) involving 1517 participants were identified in this meta-analysis. Results showed that supplemental soluble dietary fiber significantly reduced glycosylated hemoglobin (HbA1c, MD -0.63%, 95% CI [-0.90, -0.37]; P < 0.00001), fasting plasma glucose (FPG, MD -0.89 mmol/L, 95% CI [-1.28, -0.51]; P < 0.00001), fasting insulin (SMD -0.48, 95% CI [-0.80, -0.17]; P = 0.003), homeostatic model assessment of insulin resistance (HOMA-IR, SMD -0.58, 95% CI [-0.86, -0.29], P < 0.0001), fructosamine (SMD -1.03, 95% CI [-1.51, -0.55]; P < 0.0001), 2-h postprandial plasma glucose (SMD -0.74, 95% CI [-1.00, -0.48]; P < 0.00001), and BMI (SMD -0.31, 95% CI [-0.61, -0.00], P = 0.05) compared with control diets in patients with type 2 diabetes. Specifically, dose-response meta-analyses presented that a daily dosage of 7.6-8.3 g was recommended. CONCLUSION: Intake of soluble fiber supplementation is effective in improving glycemic control and BMI level in type 2 diabetes and is also a convenient way to help individuals meet standard dietary fiber needs. But due to the evidence of substantial heterogeneity in most pooled estimates, further long-term and high-quality RCTs are needed.