Konjac glucomannan (KGM), also just called ‘glucomannan’, is a dietary fiber hydro colloidal polysaccharide isolated from the tubers of Amorphophallus konjac. It is used as a food, a food additive, as well as a dietary supplement in many countries. KGM is claimed to reduce the levels of glucose, cholesterol, triglycerides, and blood pressure.
The objective of this study was to evaluate the effect of the consumption of gummy candy enriched with KGM on appetite and to evaluate anthropometric data, biochemical, and oxidative stress markers in overweight individuals. Forty-two participants aged 18 to 45 years completed this randomized, double-blind, placebo-controlled clinical trial. Participants were randomly assigned to consume for 14 days, 2 candies per day, containing 250 mg of KGM or identical-looking placebo candy with 250 mg of flaxseed meal, shortly after breakfast and dinner. As a result, we observed that there was a reduction in waist circumference and in the intensity of hunger of the participants who consumed KGM. The authors believe that a longer consumption time as well as an increased dose of KGM would contribute to even more satisfactory body results.
These findings seem promising, yet somehow I am not convinced. The study was small and short-term; moreover, the authors seem uncritical and, instead of a conclusion, they offer speculations.
Our own review of 2014 included 9 clinical studies. There was a variation in the reporting quality of the included RCTs. A meta-analysis (random effect model) of 8 RCTs revealed no significant difference in weight loss between glucomannan and placebo (mean difference [MD]: -0.22 kg; 95% confidence interval [CI], -0.62, 0.19; I(2) = 65%). Adverse events included abdominal discomfort, diarrhea, and constipation. We concluded that the evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss. Future trials should be more rigorous and better reported.
Rigorous trials are required to change my mind, and I am not sure that the new study falls into this category.
I would’ve thought that taking what is basically a mechanical appetite suppressant prior to eating would have been more appropriate if the idea is to reduce energy intake. No?
I guess there are just no robust studies yet, and what is there, is so far unconvincing.