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| IUPAC name
β(1→4)-d-gluco-d-mannoglycan
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PubChem CID
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Glucomannan is a water-soluble polysaccharide that is considered a dietary fiber. It is a hemicellulose component in the cell walls of some plant species. Glucomannan is a food additive used as an emulsifier and thickener. It is a major source of mannan oligosaccharide (MOS) found in nature, the other being galactomannan, which is insoluble.[1]
Products containing glucomannan, under a variety of brand names, are marketed as dietary supplements with claims they can relieve constipation and help lower cholesterol levels.[2][3] Since 2010 they are legally marketed in Europe as helping with weight loss for people who are overweight and eating a diet with restricted calories,[3] but as of 2020[update] there was no good evidence that glucomannan helped weight loss.[4][5] Glucomannan lowers LDL cholesterol by 10 percent.[6]
Supplements containing glucomannans pose a risk for choking and bowel obstruction if they are not taken with sufficient water.[7] Other adverse effects include diarrhea, belching, and bloating; in one study people taking glucomannans had higher triglyceride levels.[8]
Glucomannans are also used to supplement animal feed for farmed animals, to cause the animals gain weight more quickly.
- ^ Nopvichai, C; Charoenwongpaiboon, T; Luengluepunya, N; Ito, K; Muanprasat, C; Pichyangkura, R (2019). "Production and purification of mannan oligosaccharide with epithelial tight junction enhancing activity". PeerJ. 7: e7206. doi:10.7717/peerj.7206. PMC 6611449. PMID 31304065.
MOS is often prepared by hydrolysis reaction of a mannose-contained glucan polymer, mainly glucomannan and galactomannan.
- ^ "Monograph: Glucomannan - Capsule". Health Canada. May 11, 2010.
- ^ a b "Scientific Opinion on the substantiation of health claims related to konjac mannan (glucomannan) and reduction of body weight (ID 854, 1556, 3725), reduction of post-prandial glycaemic responses (ID 1559), maintenance of normal blood glucose concentration". EFSA Journal. 8 (10): 1798. October 2010. doi:10.2903/j.efsa.2010.1798.
- ^ Cite error: The named reference
whartonwas invoked but never defined (see the help page). - ^ Ríos-Hoyo A, Gutiérrez-Salmeán G (June 2016). "New Dietary Supplements for Obesity: What We Currently Know". Curr Obes Rep (Review). 5 (2): 262–70. doi:10.1007/s13679-016-0214-y. PMID 27053066. S2CID 12071766.
The more recent meta-analysis by Onakpoya et al. [58] revealed a non-statistically significant difference of −0.22 kg in weight loss between the glucomannan and placebo groups, contradicting the earlier meta-analysis. These conflicting results might be explained by the different inclusion criteria that the studies used to select the clinical trials analyzed. Although Sood et al. [59] found a statistically significant reduction in weight among study participants using glucomannan, this weight loss is not necessarily clinically significant; thus, the results should be interpreted carefully.
- ^ Ho, Hoang Vi Thanh; Jovanovski, Elena; Zurbau, Andreea; Blanco Mejia, Sonia; Sievenpiper, John L.; Au-Yeung, Fei; Jenkins, Alexandra L.; Duvnjak, Lea; Leiter, Lawrence; Vuksan, Vladimir (May 2017). "A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B". The American Journal of Clinical Nutrition. 105 (5): 1239–1247. doi:10.3945/ajcn.116.142158. ISSN 1938-3207.
- ^ "Health Canada Advises Canadians that Natural Health Products containing Glucomannan May Cause Serious Choking if Used with Insufficient Fluid". Health Canada. January 29, 2010. Archived from the original on 4 February 2010.
- ^ Cite error: The named reference
Ernst2014was invoked but never defined (see the help page).
