Comparative Effects of Psyllium and Methylcellulose on LDL Cholesterol and Glycemic Control in Type 2 Diabetes Patients: A Systematic Review and Meta-Analysis

Abstract

Type 2 diabetes (T2D) denotes a chronic metabolic disorder characterized by dyslipidemia, especially raised low-density lipoprotein cholesterol (LDL-C) increasing cardiovascular disease risk. This study aims to compare the lipid-lowering effects of psyllium and methylcellulose in adults with T2D, focusing on LDL cholesterol, total cholesterol, triglycerides and glycemic control. This study employed a systematic review and meta-analysis approach, analyzing randomized controlled trials (RCTs) and meta-analyses published between 2019 and 2024. Ten studies of 25,841 subjects were included. The studies were selected based on defined inclusion criteria that made LDL cholesterol reduction the primary outcome. The researchers extracted and analyzed the data using the weighted mean difference (WMD), and subgroup analyses, to compare the effects of psyllium and methylcellulose supplementation. Psyllium supplementation lowered LDL cholesterol significantly more than methylcellulose (−19.18 mg/dL, p < 0.001; vs. −14.2 mg/dL, p < 0.05). Psyllium also produced a greater reduction of approximately −25.3 mg/dL in total cholesterol and −15.6 mg/dL in triglycerides than methylcellulose, which produced decreases of −18.7 mg/dL in total cholesterol and −10.4 mg/dL in triglycerides. On the other hand, psyllium increased HDL cholesterol (3.1 mg/dL) and played a role in affecting glycemic parameters, while for the most part, methylcellulose could be said to affect glycemia. From the perspective of adverse effects, however, psyllium was associated with more of a gastrointestinal side effect (37% bloating/gas) as a result, with slightly lower adherence (90%) compared to methylcellulose (95%). Psyllium proves to be superior in reducing LDL cholesterol, total cholesterol, and triglycerides along with promoting glycemia, where higher levels of gasses related to inhibition of gastric emptying might lead to a reduced compliance. Methylcellulose is less effective in cystine and lipid regulation but easier on the gut and would thus be the fiber supplement of choice for patients who are gut-sensitive. The results would suggest that dietary fiber interventions can be individualized in managing cardiovascular risk for T2D patients. Future studies should focus on the long-term effects and cost-effectiveness of supplementation with psyllium or methylcellulose.