The Use of Different Reference Foods in Determining the Glycemic Index of Starchy and Non-Starchy Test Foods

Nutr J. 2014 May 31;13:50. doi: 10.1186/1475-2891-13-50.

Abstract

Background: Glycemic index (GI) is intended to be a property of food but some reports are suggestive that GI is influenced by participant characteristics when glucose is used as a reference.

Objective: To examine the influence of different reference foods on observed GI.

Design: The GIs of five varieties of rice and a sugary beverage (LoGiCane™) were tested in 31 European and 32 Chinese participants using glucose or jasmine rice as reference foods. The GIs of two ready-to-eat breakfast cereals (Kellogg's cornflakes and Sustain) were tested in 20 younger and 60 older people using glucose or Sustain as reference foods.

Results: The GIs of rice tended to be higher in the Chinese compared with the Europeans when glucose was used as a reference (jasmine 80 vs 68, P = 0.033; basmati 67 vs 57, P = 0.170; brown 78 vs 65, P = 0.054; Doongara 67 vs 55, P = 0.045; parboiled 72 vs 57, P = 0.011). There were no between-group differences in GI when jasmine rice was the reference. The GIs of breakfast cereals tended to be lower in younger compared with older groups (cornflakes 64 vs 81, P = 0.008; Sustain 56 vs 66, P = 0.054). There was no between-group difference in the GI of cornflakes when Sustain was the reference (cornflakes 115 vs 120, P = 0.64). There was no ethnic difference in GI when glucose was the reference for another sugary food (LoGiCane™ 60 vs 62; P = 0.69).

Conclusions: A starchy reference may be more appropriate than a glucose beverage when attempting to derive universally applicable GI values of starchy foods.

Trial registration: The Chinese/European trial is registered with the Australian New Zealand Clinical Trials Registry as ACTRN12612000519853.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Area Under Curve
  • Asian Continental Ancestry Group
  • Beverages / standards
  • Blood Glucose / metabolism
  • Dietary Carbohydrates / standards*
  • Edible Grain / standards
  • European Continental Ancestry Group
  • Female
  • Glucose*
  • Glycemic Index* / physiology
  • Humans
  • Male
  • Middle Aged
  • Nutritional Sciences / methods*
  • Nutritional Sciences / standards
  • Oryza*
  • Postprandial Period
  • Reference Standards*
  • Starch*

Substances

  • Blood Glucose
  • Dietary Carbohydrates
  • Starch
  • Glucose

Associated data

  • ANZCTR/ACTRN12612000519853