Plant Foods for Human Nutrition

, Volume 64, Issue 3, pp 193–198

Yam Contributes to Improvement of Glucose Metabolism in Rats

  • Naoto Hashimoto
  • Takahiro Noda
  • Sun-Ju Kim
  • Md Zaidul Islam Sarker
  • Hiroaki Yamauchi
  • Shigenobu Takigawa
  • Chie Matsuura-Endo
  • Tatsuro Suzuki
  • Kyu-Ho Han
  • Michihiro Fukushima
Original Paper

DOI: 10.1007/s11130-009-0126-z

Cite this article as:
Hashimoto, N., Noda, T., Kim, S. et al. Plant Foods Hum Nutr (2009) 64: 193. doi:10.1007/s11130-009-0126-z

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

GlycemiaGlycemic indexInsulinemiaLeptinRatsYams

Abbreviations

AUC

area under the curve

DM

diabetes mellitus

Exp.

experiment

GH

glycosylated hemoglobin

GI

glycemic index

HF

high fat diet

RS

resistant starch

SEM

standard error of the mean

TG

triacylglyceride

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Naoto Hashimoto
    • 1
  • Takahiro Noda
    • 1
  • Sun-Ju Kim
    • 1
  • Md Zaidul Islam Sarker
    • 1
    • 3
  • Hiroaki Yamauchi
    • 1
  • Shigenobu Takigawa
    • 1
  • Chie Matsuura-Endo
    • 1
  • Tatsuro Suzuki
    • 1
  • Kyu-Ho Han
    • 2
  • Michihiro Fukushima
    • 2
  1. 1.Memuro Upland Farming Research Station, National Agricultural Research Center for Hokkaido RegionMemuroJapan
  2. 2.Department of Agriculture and Life ScienceObihiro University of Agriculture and Veterinary MedicineObihiroJapan
  3. 3.Faculty of Food Science and TechnologyUniversiti Putra MalaysiaSelangorMalaysia