Glycemic and Lipid Responses to Glucomannan in Thais with Type 2 Diabetes Mellitus(cid:130)
Supornpim Chearskul MD*, Somkiat Sangurai MS*, Wannee Nitiyanant MD**, Wantanee Kriengsinyos PhD***, Suwattanee Kooptiwut MD, PhD*, Tasma Harindhanavudhi MD*
Affiliation : † The present study was supported by Siriraj Research Development Fund and Siriraj Graduate Thesis Scholarship * Department of Physiology, Faculty of Medicine, Siriraj Hospital, Mahidol University ** Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University *** Community Nutrition Division, Institute of Nutrition, Mahidol University
Objective : To evaluate the benefits of glucomannan supplement on glycemic and lipid controls in type 2
diabetic patients.
Materials and Methods : A single-blind, placebo-controlled, crossover trial with two treatments separated by a
2-week washout period was performed in 10 men and 10 women with type 2 diabetes mellitus. Two separated
protocols of experiments were sequentially followed. Initially, purified glucomannan (1 g) or placebo was
ingested 30 min before 75-g glucose load to evaluate their effects on glucose absorption and insulin secretion
in oral glucose tolerance test (OGTT). Later, the glycemic and lipid changes after 4-week intervention with 3
g/day glucomannan comparing to the placebo were determined. The standard OGTT was performed before
and after ending of each intervention.
Results : Glucomannan taken before performing the OGTT can lower the rise of blood glucose and insulin from
1 to 2 hour in comparison with the placebo, though a statistically significance of insulin was not achieved.
Long- term glucomannan supplement significantly reduced the 120-min glucose area under the curve of
OGTT. Glucomannan also decreased the rise of low-density lipoprotein cholesterol (LDL-C). Reductions of
HOMA-insulin resistance index and body mass index were detected in glucomannan-treated group though the
former was shown only in females. No within- and between-group differences of insulin, fructosamine, and
other lipids were observed in glucomannan- nor placebo- treated groups.
Conclusion : In type 2 diabetes, pre-prandial glucomannan ingestion attenuated a rise of blood glucose
without significantly affecting insulin levels. Long-term supplement of glucomannan to the regular diabetic
regimen lessened post challenge glucose AUC and impeded the rise of LDL-C. Supplement of glucomannan
may be beneficial to the glycemic and lipid controls in type 2 diabetes mellitus.
Keywords : Glucomannan, Soluble dietary fiber, Type 2 diabetes, OGTT, Thais
