Original Paper

Plant Foods for Human Nutrition

, Volume 64, Issue 3, pp 193-198

First online:

Yam Contributes to Improvement of Glucose Metabolism in Rats

  • Naoto HashimotoAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region Email author 
  • , Takahiro NodaAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Sun-Ju KimAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Md Zaidul Islam SarkerAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido RegionFaculty of Food Science and Technology, Universiti Putra Malaysia
  • , Hiroaki YamauchiAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Shigenobu TakigawaAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Chie Matsuura-EndoAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Tatsuro SuzukiAffiliated withMemuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido Region
  • , Kyu-Ho HanAffiliated withDepartment of Agriculture and Life Science, Obihiro University of Agriculture and Veterinary Medicine
    • , Michihiro FukushimaAffiliated withDepartment of Agriculture and Life Science, Obihiro University of Agriculture and Veterinary Medicine

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

To investigate whether yam improves glucose metabolism, yam-containing diets were given to Wistar rats. In a short-term experiment, fasted-rats were given 1.0 g of a control and 20% yam-containing diets. At 60 min after start of the feeding, glucose level in the yam diet group was lower or tended to be lower than that in the control diet. Insulin levels at 30 min and 60 min were significantly lower than those in the control group. In a long-term experiment, a normal diet (N) or 25% high fat diets with (Y) or without 15% yam powder (HF) were given to rats for 4 weeks. At 4 weeks, in an oral glucose tolerance test, the area under the curve (AUC) of plasma glucose level was higher in the HF group than that in the N group, whereas those in the Y groups did not differ from that in the N group. Glycosylated hemoglobin levels had similar tendency to the AUCs. Plasma leptin levels in the Y groups were significantly higher than that in the N group. In conclusion, yam may contribute to improvement of glucose metabolism. Additionally, we speculated that leptin level is possibly involved in the insulin-response to yam diets.

Keywords

Glycemia Glycemic index Insulinemia Leptin Rats Yams