Konjac Glucomannan, Weight Loss, and Microbiome health

Obesity seems to be less common in populations that consume large amounts of Glucomannan. Glucomannan has been shown to promote weight loss. It can do this by reducing total energy intake and therefore inducing satiety. In this way, it can prevent the overeating that contributes to excess weight.

Moreover, soluble dietary fibre such as glucomannan can also aid with weight regulation in how it can change the composition of gut microbiota. Digesting glucomannan can alter the intestinal microbiota of an individual into one that favours healthy bacteria such as Bacteroidetes, and therefore into one that favours weight regulation.

jump to detailed reading

Glucomannan’s effects on body weight

Satiety and weight loss

Glucomannan is an extremely low energy density food
  • For this reason, it can promote an overall reduction in total energy intake
  • Reducing total energy intake can promote weight loss
Glucomannan gel has high firmness
  • When digested, glucomannan can delay the process of food being emptied from the stomach and sustain satiety
  • Glucomannan gel also exceeds the force that is typically exerted by the stomach during digestion
  • As a result, it can be retained in the stomach longer and create a feeling of fullness
  • In this way, it can prevent the overeating that contributes to excess weight

Gut microbiota and BMI (body mass index)

The human gastrointestinal tract is a thriving environment filled with microbial life
  • These environments are unique to every individual
  • Most healthy adult microbiota are dominated by two kinds of bacteria:

Firmicutes and Bacteroidetes

    A high ratio of Firmicutes to Bacteroidetes has been associated with a high BMI
    • And vice versa - a high ratio of Bacteroidetes to Firmicutes has been associated with a low BMI
    • Firmicutes can more efficiently absorb calories, leading to weight gain
    • This suggests that promoting a high level of Bacteroidetes compared to Firmicutes can aid towards weight regulation

    Bacteria are most dense in the colon

    • Here, most of the simple, readily accessible sugars that come from food have already been absorbed by other microorganisms
    • What’s left over are complex long-chain polysaccharides

    Dietary fibres such as glucomannan are polysaccharides

    • These polysaccharides are not freely absorbed and cannot be digested by human enzymes  
    • Bacteroides, a genus of Bacteroidetes, thrive on these polysaccharides

    Diets that are high in fibre are high in polysaccharides are therefore high in Bacteroides

    • A high-fibre diet increases the amount of Bacteroides
    • And vice versa - a low-fibre diet increases the ratio of Firmicutes to Bacteroidetes
    • Glucomannan can alter the intestinal microbiota into one that favours Bacteroidetes and weight regulation

    Read these points in more detail here.

    References

    1. Au-Yeung F, Jovanovski E, Jenkins AL, et al. “The effects of gelled konjac glucomannan fibre on appetite and energy intake in healthy individuals: a randomised cross-over trial”. British Journal of Nutrition Vol. 119 No. 1 (2018): 109-116.

    2. Koliadam A, Syzenko G, Moseiko V, et al. “Association between body mass index and Firmicutes/Bacteroidetes ratio in an adult Ukrainian population”. BMC Microbiology Vol. 17 No. 1 (2017): 1-6.

    3. Marciani L, Gowland P, Fillery-Travis A, et al. “Assessment of antral grinding of a model solid meal with echo-planar imaging”. The American Journal of Physiology, Vol. 280 No. 5 (2001): G844–G849.

    4. Salas-Salvado S, Farres X, Luque X, et al. “Effect of two doses of a mixture of soluble fibres on body weight and metabolic variables in overweight or obese patients: a randomised trial”. British Journal of Nutrition Vol. 99 No. 6 (2008): 1380-1387.

    5. Trompette A, Gollwitzer, E., Yadava K., et al. “Gut microbiota metabolism of dietary fibre influences allergic airway disease and hematopoiesis”. Nature Medicine Vol. 20 No. 2 (2014): 159-167.

    6. Wang H, Hong T, Li N, et al. “Soluble dietary fiber improves energy homeostasis in obese mice by remodeling the gut microbiota”. Biochemical and Biophysical Research Communications Vol. 498 No. 1 (2018): 146-151.

    7. Wexler AG, Goodman AL. “An insider’s perspective: Bacteroides as a window into the microbiome”. Nature Microbiology Vol. 2. No. 5 (2017): 17026.

    8. Young W, Roy NC, Lee J, et al. “Bowel Microbiota Moderate Host Physiological Responses to Dietary Konjac in Weanling Rats” in The Journal of Nutrition Vol. 143 No. 7 (2013): 1052-1060.