European Journal of Nutrition

, Volume 57, Issue 6, pp 2217–2225 | Cite as

Co-administration of a konjac-based fibre blend and American ginseng (Panax quinquefolius L.) on glycaemic control and serum lipids in type 2 diabetes: a randomized controlled, cross-over clinical trial

  • Alexandra L. Jenkins
  • Linda M. Morgan
  • Jacqueline Bishop
  • Elena Jovanovski
  • David J. A. Jenkins
  • Vladimir VuksanEmail author
Original Contribution



Use of polypharmacy in the treatment of diabetes is the norm; nonetheless, optimal control is often not achieved. Konjac-glucomannan-based fibre blend (KGB) and American ginseng (AG) have individually been shown to improve glycaemia and CVD risk factors in type 2 diabetes. The aim of this study was to determine whether co-administration of KGB and AG could improve diabetes control beyond conventional treatment.


Thirty-nine participants with type 2 diabetes (6.5 > A1c < 8.4%) were enrolled between January 2002 and May 2003 at the Risk Factor Modification Centre at St Michaels Hospital in a randomized, placebo-controlled, crossover trial with each intervention lasting 12-weeks. Medications, diet and lifestyle were kept constant. Interventions consisted of 6 g of fibre from KGB together with 3 g of AG (KGB and AG) or wheat bran-based, fibre-matched control. Primary endpoint was the difference in HbA1c levels at week 12.


Thirty participants (18M:12F; age: 64 ± 7 years; BMI: 28 ± 5 kg/m2; HbA1c: 7.0 ± 1.0%) completed the study, and consumed 5.5 and 4.9 g/day of fibre from KGB and wheat bran control, respectively, and 2.7 g/day of AG. At week 12, HbA1c levels were 0.31% lower on the KGB and AG compared to control (p = 0.011). Mean (±SEM) plasma lipids decreased on the KGB and AG vs control by 8.3 ± 3.1% in LDL-C (p = 0.002), 7.5 ± 2.4% in non-HDL-C (p = 0.013), 5.7 ± 1.9% in total-C (p = 0.012), 4.1 ± 2.1% in total-C:HDL-C ratio (p = 0.042), 9.0 ± 2.3% in ApoB (p = 0.0005) and 14.6 ± 4.2% in ApoB:ApoA1 ratio (p = 0.049).


Co-administration of KGB and AG increases the effectiveness of conventional therapy through a moderate but clinically meaningful reduction in HbA1c and lipid concentrations over 12 weeks in patients with type 2 diabetes.

Clinical Trials Registration

NCT02806349 (


Type 2 diabetes Dietary fibre American ginseng Konjac mannan Glucomannan Xanthan 


Author contributions

The contributions of the authors were as follows—AJ: obtained the funding, wrote the protocol, coordinated the study, conducted data analysis and manuscript preparation VV: conceived the project and development of overall research plan, contributed to the study design, and preparation of the manuscript; DJ: contributed to the study design, data interpretation and manuscript preparation; LM, JB and EJ: contributed to the study design, interpretation and critically reviewed the manuscript. All authors read and approved the final manuscript.

Compliance with ethical standards

Sources of support

Operating grant was received from the Canadian Diabetes Association and in kind donation of American ginseng from the Ontario Ginseng Growers Association. At the time of the study, ALJ was the recipient of a personnel award from the Heart and Stroke Foundation of Canada.

Conflict of interest

ALJ is vice president and partial owner of Glycemic Index Laboratories, Inc. (Toronto, ON, Canada) a clinical research organization; V. V. holds an American (No. 7,326,404 B2) and Canadian (No. 2,410,556) patent for use of viscous fibre blend in diabetes, metabolic syndrome and cholesterol lowering. He was also a consultant for InovoBiologic (Calgary, Al., Canada), the producer of the viscous fibre blend commercially known as PGX™ which was developed based on Dr. Vuksan’s work. V. V was partial owner of Glycemic Index Laboratories, Inc. (Toronto, ON, Canada) during 2004–2015; LM, JB and EJ have no conflicts of interest; DJAJ was funded by the Government of Canada through the Canada Research Chair Endowment. DJAJ has received research grants from Saskatchewan Pulse Growers, the Agricultural Bioproducts Innovation Program through the Pulse Research Network, the Advanced Foods and Material Network, Loblaw Companies Ltd., Unilever, Barilla, the Almond Board of California, Agriculture and Agri-food Canada, Pulse Canada, Kellogg’s Company, Canada, Quaker Oats, Canada, Procter & Gamble Technical Centre Ltd., Bayer Consumer Care, Springfield, NJ, Pepsi/Quaker, International Nut & Dried Fruit (INC), Soy Foods Association of North America, the Coca-Cola Company (investigator initiated, unrestricted grant), Solae, Haine Celestial, the Sanitarium Company, Orafti, the International Tree Nut Council Nutrition Research and Education Foundation, the Peanut Institute, the Canola and Flax Councils of Canada, the Calorie Control Council (CCC), the CIHR, the Canada Foundation for Innovation and the Ontario Research Fund. He has been on the speaker’s panel, served on the scientific advisory board and/or received travel support and/or honoraria from the Almond Board of California, Canadian Agriculture Policy Institute, Loblaw Companies Ltd, the Griffin Hospital (for the development of the NuVal scoring system, the Coca-Cola Company, EPICURE, Danone, Saskatchewan Pulse Growers, Sanitarium Company, Orafti, the Almond Board of California, the American Peanut Council, the International Tree Nut Council Nutrition Research and Education Foundation, the Peanut Institute, Herbalife International, Pacific Health Laboratories, Nutritional Fundamental for Health, Barilla, Metagenics, Bayer Consumer Care, Unilever Canada and Netherlands, Solae, Kellogg, Quaker Oats, Procter & Gamble, the Coca-Cola Company, the Griffin Hospital, Abbott Laboratories, the Canola Council of Canada, Dean Foods, the California Strawberry Commission, Haine Celestial, PepsiCo, the Alpro Foundation, Pioneer Hi-Bred International, DuPont Nutrition and Health, Spherix Consulting and WhiteWave Foods, the Advanced Foods and Material Network, the Canola and Flax Councils of Canada, the Nutritional Fundamentals for Health, Agri-Culture and Agri-Food Canada, the Canadian Agri-Food Policy Institute, Pulse Canada, the Saskatchewan Pulse Growers, the Soy Foods Association of North America, the Nutrition Foundation of Italy (NFI), Nutra-Source Diagnostics, the McDougall Program, the Toronto Knowledge Translation Group (St. Michael’s Hospital), the Canadian College of Naturopathic Medicine, The Hospital for Sick Children, the Canadian Nutrition Society (CNS), the American Society of Nutrition (ASN), Arizona State University, Paolo Sorbini Foundation and the Institute of Nutrition, Metabolism and Diabetes. He received an honorarium from the United States Department of Agriculture to present the 2013 W.O. Atwater Memorial Lecture. He received the 2013 Award for Excellence in Research from the International Nut and Dried Fruit Council. He received funding and travel support from the Canadian Society of Endocrinology and Metabolism to produce mini cases for the Canadian Diabetes Association (CDA). He is a member of the International Carbohydrate Quality Consortium (ICQC). His wife, ALJ, is a director and partner of Glycemic Index Laboratories, Inc., and his sister received funding through a grant from the St. Michael’s Hospital Foundation to develop a cookbook for one of his studies.

Supplementary material

394_2017_1496_MOESM1_ESM.docx (43 kb)
Supplementary material 1 (DOCX 42 kb)


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Clinical Nutrition and Risk Factor Modification CentreSt. Michael’s HospitalTorontoCanada
  2. 2.Department of Nutritional Sciences, Faculty of MedicineUniversity of TorontoTorontoCanada
  3. 3.Department of Medicine, Faculty of MedicineUniversity of TorontoTorontoCanada
  4. 4.Li Ka Shing Knowledge Institute, St Michael’s HospitalTorontoCanada
  5. 5.Department of Nutritional Sciences, School of Biosciences and MedicineUniversity of SurreyGuildfordUK

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