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Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis.

Aim: to better characterize glucomannan’s impact on plasma lipids, body weight and blood pressure.

Study design: a systematic literature search

Subjects: 531 patients having at least one, if not, multiple, constituents of the metabolic syndrome, including type 2 diabetes mellitus or impaired glucose tolerance, hyperlipidemia, hypertension, or obesity. The dosage range of glucomannan ranged from 1,2 to 15,1 g/d and were administered in various forms, such as capsules, tablets, bars, biscuits, and refined konjac mealfor 3-16 weeks.

Results: the use of glucomannan significantly lowered total cholesterol [weighted mean difference (WMD): -19.28 mg/dL; 95% CI:-24.30, -14.26], LDL cholesterol (WMD: 15.99 mg/dL; 95% CI: 21.31,-10.67), triglycerides (WMD: 11.08 mg/dL; 95% CI: -22.07, -0.09), body weight (WMD: -0.79 kg; 95% CI: -1.53, -0.05) and fasting blood glucose (WMD:-7.44 mg/dL; 95% CI:-14.16,-0.72). In studies lasting a mean of 5,2 weeks, the meta-analysis found that there was a statistically significant but small reduction in weight of 1,74 lb (~1%) with glucomannan. Pediatric patients, patients receiving dietary modification, and patients with impaired glucose metabolism did not benefit from glucomannan to the same degree.

Authors’ conclusion: glucomannan appears to beneficially affect total cholesterol, LDL cholesterol, triglycerides, body weight, and fasting blood glucose, but not HDL cholesterol or blood pressure.

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