Endocrinology · Medical Literature
[The Effect of Konjac Glucomannan on Blood Glucose and Insulin Levels in Obese Patients With Prediabetes].
Abstract
To investigate the effects of konjac glucomannan (KGM) on glycemic indicators and insulin resistance in obese individuals with prediabetes. A total of 102 obese individuals diagnosed with prediabetes at the outpatient department of West China Hospital, Sichuan University, between July 2021 and June 2022 were recruited and randomly assigned to either the experimental group (KGM group) or the control group for a three-month trial. All subjects followed personalized dietary and exercise regimens, with the KGM group additionally consuming 60 g of konjac-based dietary fiber biscuits daily to partially replace carbohydrates. This study aimed to examine the impact of KGM on fasting blood glucose, and to explore changes in 2-hour postprandial glucose, insulin-related indicators, and obesity-related parameters in the two groups of subjects. A total of 41 participants in the KGM group completed the trial, with a compliance rate of 77.36%. The control group had 38 completers, with a compliance rate of 77.55%. After three months of dietary and exercise intervention, the effective rate of fasting blood glucose control was 100% in the KGM group, significantly higher than the 82% observed in the control group. The KGM group also had higher effective rates in reducing fasting blood glucose, fasting insulin, insulin resistance, insulin sensitivity, body mass, and waist circumference compared to the control group (P 0.05). During the trial, two participants in the KGM group experienced severe abdominal discomfort, which resolved after discontinuing the biscuits; two cases reported transient diarrhea, and one case reported increased anal flatulence. KGM can effectively control fasting blood sugar and promotes weight loss, lowers blood sugar, and enhances insulin sensitivity in obese individuals with prediabetes.
Clinical relevance
In obese adults with prediabetes undergoing lifestyle intervention, does daily supplementation with konjac glucomannan (KGM) dietary fiber biscuits (60 g/day) improve fasting blood glucose control rates and insulin resistance indicators compared with lifestyle intervention alone over three months? __SNAPSHOT__ {"studyDesign":"Randomized controlled trial (parallel-group, two-arm)","setting":"Outpatient department, West China Hospital, Sichuan University, China; single-center","sampleSize":"n=102 enrolled (KGM group: n=53 enrolled, n=41 completed; control group: n=49 enrolled, n=38 completed); completers: n=79","population":"Obese adults diagnosed with prediabetes, recruited July 2021–June 2022; specific age range, sex distribution, BMI thresholds, and prediabetes diagnostic criteria (e.g., ADA vs. WHO) not reported in the abstract","intervention":"Personalized dietary and exercise regimen PLUS 60 g/day of konjac-based dietary fiber biscuits (KGM-enriched) as partial carbohydrate replacement, for 3 months","comparator":"Personalized dietary and exercise regimen alone (lifestyle intervention without KGM supplementation), for 3 months","primaryOutcome":"Effective rate of fasting blood glucose (FBG) control at 3 months; secondary outcomes included 2-hour postprandial glucose (2hPG), insulin-related indicators (specific indices not detailed in abstract), and obesity-related parameters","followUp":"3 months","fundingSource":"Not reported"}
Key findings
Among trial completers, the effective rate of FBG control at 3 months was 100% in the KGM group (41/41) compared with 82% in the control group (approximately 31/38, calculated). This difference was reported as statistically significant; however, the specific p-value, confidence interval, and definition of 'effective FBG control' (i.e., the threshold used) were not provided in the available abstract. Absolute risk difference: approximately 18 percentage points (calculated); relative risk reduction: approximately 22% (calculated); NNT: approximately 6 (calculated). Results for 2-hour postprandial glucose, insulin resistance indices, and obesity-related parameters were noted as secondary outcomes but quantitative results, effect sizes, confidence intervals, and p-values for these endpoints were not reported in the abstract. Compliance rates were nearly identical between arms (KGM: 77.36%; control: 77.55%), suggesting comparable adherence and limiting differential dropout as a major source of bias. Adverse events were not reported in the available abstract.
Practice implications
This single-center RCT suggests that adding 60 g/day of KGM-enriched biscuits to a structured lifestyle program may substantially improve the rate of FBG normalization in obese prediabetic adults at 3 months, with a calculated NNT of approximately 6. However, several critical interpretive constraints apply: (1) Only an abstract is available; the full dataset, including definitions of 'effective FBG control,' absolute glucose values, HbA1c, HOMA-IR or equivalent insulin resistance indices, and between-group comparisons for all secondary endpoints, has not been reviewed. (2) The study was conducted at a single Chinese tertiary academic center, limiting generalizability to other ethnic groups, healthcare settings, and prediabetes populations managed by primary care. (3) The trial duration of 3 months is insufficient to assess conversion to type 2 diabetes, durability of glycemic benefit, or long-term safety. (4) Blinding status is not reported; given the nature of the intervention (food product replacing carbohydrates), participant blinding is likely impractical, introducing performance bias risk. (5) The 'effective rate' metric is a composite or threshold-based endpoint whose clinical meaning depends entirely on the cutoff used—this cutoff was not specified in the abstract. (6) The 100% control rate in the KGM group is a ceiling effect that, while striking, should be interpreted with caution given the small completer sample (n=41) and short follow-up. Results should be regarded as hypothesis-generating; practice change is not warranted without review of the full publication and independent replication. __LIMITATIONS__ Only an abstract is available; full methodology, statistical analysis plan, and complete results cannot be evaluated.,Single-center design at a Chinese tertiary hospital limits generalizability to other populations and healthcare systems.,Small sample size (79 completers) reduces statistical power for secondary endpoints and increases susceptibility to type I error.,Definition of 'effective FBG control' is not stated in the abstract, making the primary outcome clinically uninterpretable without the full paper.,Three-month follow-up is insufficient to assess progression to T2DM, sustainability of effect, or long-term safety.,Blinding: not reported; open-label design is likely given the food-based intervention, introducing performance and detection bias.,The intervention involved both KGM biscuits AND partial carbohydrate replacement, making it impossible to attribute effects solely to KGM versus reduced total carbohydrate intake.,Per-protocol analysis of completers only (dropouts ~23% per arm) may introduce attrition bias if non-completers differed systematically.,No adverse event data reported in the abstract.,Funding source not disclosed; potential conflicts of interest cannot be assessed.,Absence of HbA1c as an outcome limits long-term glycemic interpretation.,100% effective rate in the KGM group represents a ceiling effect that may reflect selection or small-sample artifact. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This small, single-center RCT reports a 100% vs. 82% fasting blood glucose control rate favoring KGM dietary fiber supplementation added to lifestyle intervention in obese prediabetic adults, corresponding to a calculated NNT of approximately 6 at 3 months. However, the study is limited by its small completer sample, single-center design, short follow-up, unclear outcome definition, likely open-label conduct, and confounded intervention (KGM plus carbohydrate substitution). These findings are preliminary and hypothesis-generating; clinicians should await full publication and independent replication before incorporating KGM supplementation into routine prediabetes management protocols.