Kindly provide info & studies about health benefits of Konjac/ Konnyaku.


Glucomannan is a water-soluble, fermentable dietary fiber that is extracted from the tuber or root of the elephant yam, also known as konjac (Amorphophallus konjac) (Keithley et al., 2013). Konjac has multiple benefits to obesity and diabetes diseases besides helping in constipation relieve. It also plays an important role as a prebiotic by inducing beneficial bacteria in our guts, while having an anti-hypercholesterolemia effect as a soluble dietary fiber in human (Dai et al., 2016). Moreover, konjac is a nutritious plant and is commonly used in the food industry for its gelling properties (Khan & Marya, 2019).

Authors Findings and Description
Janani & Changaee, 2018
  • 64 pregnant women in their third trimester of pregnancy with constipation were investigated in the two groups of intervention (treated with glucomannan) and control (magnesium hydroxide)
  • About 75% of the participants in the glucomannan group reported having at least 6 times of bowel movements
  • The findings indicated that using glucomannan is highly effective for treating pregnancy constipation through increase of bowel movements frequency and stool consistency, no serious complication was reported
Ho et al., 2017
  • A total of 12 studies (n = 370), 8 in adults and 4 in children, were included in this meta-analysis
  • Consumption of approximately 3 g/d of glucomannan reduced significantly LDL (low-density lipoprotein) cholesterol and non-HDL (high-density lipoprotein) cholesterol by 10% and 7% respectively
  • Evidence suggests that viscous konjac fiber enhances intestinal viscosity which impairs uptake of dietary cholesterol and prevents the reabsorption of bile acids
Kaats et al., 2015
  • A total of 83 overweight adults (66 women and 17 men) were investigated in two groups of intervention (treated with 3g glucomannan + 300mg calcium carbonate) and control group (300mg calcium carbonate) for 60 days
  • Significant reductions in scale weight, percentage body fat, fat mass, total cholesterol, and LDL cholesterol were found in the glucomannan group compared to the control group
  • The ability of glucomannan to quickly and profoundly absorb water suggests that it may lead to a swelling in the stomach, resulting in consequent feelings of fullness and decreased appetite
Shah et al., 2015
  • Glucomannan increases transit time of food and prolongs gastric emptying time, which increases satiety and reduces body weight
  • It decreases the ingestion of foods that increase cholesterol and glucose concentrations, reduces the postprandial (after eating a meal) rise in plasma glucose, suppresses cholesterol synthesis in liver, and increases the stool  elimination of cholesterol containing bile acids
Suwannaporn et al., 2015
  • 20 adult volunteers were given drinks containing 3g active glucomannan hydrolysates for 14 days
  • The average fasting blood glucose at the start of the trial was 2.54 mmol/L but reduced slightly to 2.49 mmol/L after consumption of the glucomannan
  • The total average cholesterol and triglyceride reduced 3.74% & 11.5% after consuming the glucomannan while both parameters for HDL and LDL were reduced by over 3%
  • The consumption of the glucomannan hydrolysates also reduced the total cholesterol/ HDL and LDL/HDL ratios
Al-Ghazzewi & Tester, 2014
  • The ability of glucomannan hydrolysates to function a prebiotic and their specific capacity to inhibit certain bacteria (especially E. coli) from attaching to epithelial cells in the gut may reduce pathogen bacterial colonization
  • This binding could prevent the pathogens ability to inititiate and induce chronic immune inflammation of the bowel mucosa
Hickey, 2012; Suwannaporn et al., 2013
  • Glucomannan hydrolysates were tolerated well for patients with diarrhea and had a significant improvement on bowel movement, stool consistency, abdominal pain and flatulence (buildup of gas in the digestive system)
  • It creates a healthy gut microbiota to help counter the underlying cause of inflammation
Al-Sheraji et al., 2013; Mudgil & Barak, 2013
  • Glucomannan is indigestible in small intestine and then partially or completely fermented by gut bacteria; therefore, it can act as prebiotic that stimulate the growth of probiotic bacteria thereby enhancing short-chain fatty acids (SCFAs) production, reduce the number of bad pathogenic bacterial populations and thereby improving the immune system

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Al-Ghazzewi, F., & Tester, R. (2014). Inhibition of the adhesion of Escherichia coli to human epithelial cells by carbohydrates. Bioactive Carbohydrates And Dietary Fibre, 4(1), 1-5.

Al-Sheraji, S., Ismail, A., Manap, M., Mustafa, S., Yusof, R., & Hassan, F. (2013). Prebiotics as functional foods: A review. Journal Of Functional Foods, 5(4), 1542-1553.

Dai, S., Corke, H., & Shah, N. P. (2016). Utilization of konjac glucomannan as a fat replacer in low-fat and skimmed yogurt. Journal Of Dairy Science, 99(9), 7063-7074.

Hickey, R. (2012). The role of oligosaccharides from human milk and other sources in prevention of pathogen adhesion. International Dairy Journal, 22(2), 141-146.

Ho, H. V. T., Jovanovski, E., Zurbau, A., Mejia, S. B., Sievenpiper, J. L., Yeung, F. A., Jenkins, A. L., Duvnjak, L., Leiter, L., & Vuksan, V. (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.

Janani, F., & Changaee, F. (2018). The effect of glucomannan on pregnancy constipation. Journal of Family Medicine and Primary Care, 7(5):903-906.

Kaats, G., Bagchi, D., & Preuss, H. (2015). Konjac Glucomannan Dietary Supplementation Causes Significant Fat Loss in Compliant Overweight Adults. Journal Of The American College Of Nutrition, 0(0), 1-7.

Keithley, J., Swanson, B., Mikolaitis, S., DeMeo, M., Zeller, J., Fogg, L., & Adamji, J. (2013). Safety and Efficacy of Glucomannan for Weight Loss in Overweight and Moderately Obese Adults. Journal Of Obesity, 2013, 1-7.

Khan, H., & Marya. (2019). Konjac (Amorphophallus konjac). Nonvitamin And Nonmineral Nutritional Supplements, 307-312.

Mudgil, D., & Barak, S. (2013). Composition, properties and health benefits of indigestible carbohydrate polymers as dietary fiber: A review. International Journal Of Biological Macromolecules, 61, 1-6.

Shah, B., Li, B., Wang, L., Liu, S., Li, Y., & Wei, X. et al. (2015). Health benefits of konjac glucomannan with special focus on diabetes. Bioactive Carbohydrates And Dietary Fibre, 5(2), 179-187.

Suwannaporn, P., Tester, R., Al-Ghazzewi, F., & Artitdit, P. (2015). Effect of short term administration of konjac glucomannan hydrolysates on adult blood lipid parameters and glucose concentrations. Nutrition & Food Science, 45(4), 616-624.

Suwannaporn, P., Thepwong, K., Tester, R., Al-Ghazzewi, F., Piggott, J., & Shen, N. et al. (2013). Tolerance and nutritional therapy of dietary fibre from konjac glucomannan hydrolysates for patients with inflammatory bowel disease (IBD). Bioactive Carbohydrates And Dietary Fibre, 2(2), 93-98.