Konjac glucomannan
Glucomannan/Drug Interactions:
NoteNote: Increased consumption of dietary fibers is thought to have the potential to modify the bioavailability of other agents, including prescription and nonprescription drugs, herbs, and supplements. Separating the ingestion of any fiber supplement by two hours from other foods, pharmaceutical agents, herbal products, or dietary supplements is suggested.AntibioticsAntibiotics: In human research, the addition of the antibiotic rifaximin to glucomannan treatment of patients with uncomplicated diverticular disease reduced symptoms of the disease (abdominal pain, discomfort, tenderness, bloating, tenesmus, and diarrhea) (5) and improved clinical score (4; 49) over glucomannan alone. Antidiabetic agentsAntidiabetic agents: In human research, glucomannan significantly lowered fasting blood glucose (11; 14). In human research, glucomannan reduced the intestinal absorption of the sulfonylurea glibenclamide (22). AntihypertensivesAntihypertensives: In human research, glucomannan lowered blood pressure (17). AntilipemicsAntilipemics: In human research, glucomannan significantly lowered blood levels of total and low-density lipoprotein (LDL) cholesterol, apolipoprotein (apo) B, and triglycerides (11; 12; 14; 16; 15). AntineoplasticAntineoplastics: Fecal water from glucomannan supplementation of animals reduced the cytotoxicity and DNA damage of fecal water-treated Caco-2 cells in vitro, potentially by increasing fecal probiotics and ferrous iron-chelating activities (50). Antiobesity agentsAntiobesity agents: In human research, use of glucomannan reduced body weight in overweight or obese individuals (11; 35; 36; 51). ImmunosuppressantsImmunosuppressants: In animal research, molecules related to konjac glucomannan (polyactin A, an alpha-glucomannan isolated from Streptococcus) were found to antagonize the immunosuppressive actions of cyclophosphamide (8). It is not clear if konjac glucomannan has these abilities. In animal research, dietary konjac glucomannan prevented lymphadenopathy, splenomegaly, and increases in anti-dsDNA, rheumatoid factor IgG autoantibodies, and the B cell-activating factor of the tumor necrosis factor (TNF) family (2). The same group also determined that low viscous glucomannan was preferable in terms of immunoregulatory function in the atopic dermatitis animal model (23). LactuloseLactulose: A combination of lactulose and glucomannan induced a return to the normal frequency of the weekly number of fecal evacuations in pregnant women (52). LaxativesLaxatives: According to human research, glucomannan may relieve constipation and have a bulk laxative effect (19; 20; 27; 28; 30). Thyroid hormonesThyroid hormones: In human research, glucomannan reduced serum T3, T4, FT3, and FT4 levels, without affecting thyroid-stimulating hormone (TSH) (24). Glucomannan/Herb/Supplement Interactions:
NoteNote: Increased consumption of any dietary fiber is thought to have the potential to modify the bioavailability of other agents, including prescription and nonprescription drugs, herbs, and supplements. Separating the ingestion of any fiber supplement by two hours from other foods, pharmaceutical agents, herbal products, or dietary supplements is suggested.American ginsengAmerican ginseng: Given the different mechanisms of action of glucomannan and American ginseng, scientific interest as to their potential additive effects exists with respect to glucose lowering (53). AntibacterialsAntibacterials: In human research, the addition of an antibiotic to glucomannan treatment of patients with uncomplicated diverticular disease reduced symptoms of the disease (abdominal pain, discomfort, tenderness, bloating, tenesmus, diarrhea) (5) and improved clinical score (4; 49) vs. glucomannan alone. AntilipemicsAntilipemics: In human research, glucomannan significantly lowered blood levels of total and LDL cholesterol, apo B, and triglycerides (11; 12; 14; 16; 15). AntineoplasticsAntineoplastics: Fecal water from glucomannan supplementation of animals reduced the cytotoxicity and DNA damage of Caco-2 cells in vitro, potentially by increasing fecal probiotics and ferrous iron-chelating activities (50). Antiobesity agentsAntiobesity agents: In human research, use of glucomannan reduced body weight in overweight or obese individuals (11; 35; 36; 51). Fat-soluble vitaminsFat-soluble vitamins: In human research, glucomannan resulted in decreased absorption of vitamin E (25). It is possible that other fat-soluble vitamins are also affected. However, the combination of glucomannan and chitosan had no effect on various fat-soluble vitamins (vitamin A, vitamin E, 25-hydroxyvitamin D) or carotenes in a study investigating this combination in men and women (13). HypoglycemicsHypoglycemics: In human research, glucomannan significantly lowered fasting blood glucose (11; 14). HypotensivesHypotensives: In human research, glucomannan lowered blood pressure (17). ImmunomodulatorsImmunomodulators: In animal research, molecules related to konjac glucomannan (polyactin A, an alpha-glucomannan isolated from Streptococcus) were found to antagonize the immunosuppressive actions of cyclophosphamide (8). It is not clear if konjac glucomannan has these abilities. In animal research, dietary konjac glucomannan prevented lymphadenopathy, splenomegaly, and increases in anti-dsDNA, rheumatoid factor IgG autoantibodies, and the B cell-activating factor of the TNF family (2). The same group also determined that low viscous glucomannan was preferable in terms of immunoregulatory function in the atopic dermatitis animal model (23). LaxativesLaxatives: According to human research, glucomannan may relieve constipation and have a bulk laxative effect (19; 20; 27; 28; 30). Plant sterolsPlant sterols: The combination of plant sterols plus glucomannan resulted in a reduction in cholesterol levels in human research (12). Plasma lathosterol concentrations were lower after the combination treatment than after plant sterols alone. Thyroid agentsThyroid agents: In human research, glucomannan reduced serum T3, T4, FT3, and FT4 levels, without affecting TSH (24). Glucomannan/Food Interactions:
FiberFiber: Theoretically, consumption of glucomannan could have additive effects with other soluble and insoluble fibers.Glucomannan/Lab Interactions:
Blood pressureBlood pressure: In human research, glucomannan lowered blood pressure (17). Breath hydrogenBreath hydrogen: In human research, glucomannan tended to decrease expiratory breath hydrogen (34; 48). Fat-soluble vitaminsFat-soluble vitamins: In human research, glucomannan resulted in decreased absorption of vitamin E (25). However, the combination of glucomannan and chitosan had no effect on various fat-soluble vitamins (vitamin A, vitamin E, 25-hydroxyvitamin D) or carotenes in a study investigating this combination in men and women (13). Fecal compoundsFecal compounds: Information from animal research suggests that glucomannan may exert its gastrointestinal effects by reducing fecal beta-glucuronidase, nitroreductase, and azoreductase activities, as well as the production of fecal phenol, cresol, and indole (54). Fecal probioticsFecal probiotics: In animal research, glucomannan changed the microbial composition of feces, including increased frequency of Bifidobacterium, Lactobacilli, and Enterobacteriaceae (54; 55; 28; 30). FructosamineFructosamine: In human research, glucomannan significantly lowered serum fructosamine (16). GhrelinGhrelin: In human research, glucomannan enhanced plasma ghrelin when given before a glucose load and impeded the rise of fasting ghrelin (21). GlucoseGlucose: In human research, glucomannan significantly lowered fasting blood glucose (11; 14). Immune panelImmune panel: In animal research, dietary konjac glucomannan prevented increases in anti-dsDNA, rheumatoid factor IgG autoantibodies, and the B cell-activating factor of the TNF family (2). InsulinInsulin: In hypoglycemic patients, glucomannan decreased the rise in postprandial insulin (34). In obese subjects, glucomannan lowered postprandial insulin (56). InterleukinsInterleukins: In vitro, glucomannans from Candida utilis reduced the ultraviolet-induced gene expression of proinflammatory markers such as interleukin-8 (IL-8) and IL-1, as well as the release of IL-1alpha protein (57). It is not clear if konjac glucomannans would have the same effect. Lipid profileLipid profile: In human research, glucomannan significantly lowered blood levels of total and LDL cholesterol, apo B, and triglycerides (11; 12; 14; 16; 15). In children, glucomannan reduced levels of alpha-lipoprotein and increased levels of pre-beta-lipoprotein and triglycerides (38). ProstaglandinProstaglandin: In vitro, glucomannans from Candida utilis reduced the ultraviolet-induced release of prostaglandin E2 (57). It is not clear if konjac glucomannans would have the same effect. Thyroid hormonesThyroid hormones: In human research, glucomannan reduced serum T3, T4, FT3, and FT4 levels, without affecting TSH (24).