Low–Glycemic Index Diets in the Management of Diabetes

A meta-analysis of randomized controlled trials

  1. Jennie Brand-Miller, PHD1,
  2. Susan Hayne, BSC2,
  3. Peter Petocz, PHD2 and
  4. Stephen Colagiuri, MD3
  1. 1Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia
  2. 2Department of Mathematical Sciences, University of Technology, Sydney, Australia
  3. 3Department of Endocrinology, Diabetes and Metabolism, Prince of Wales Hospital, Sydney, Australia
  1. Address correspondence and reprint requests to Professor J. Brand-Miller, Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006 Australia. E-mail: j.brandmiller{at}mmb.usyd.edu.au

Abstract

OBJECTIVE—The use of diets with low glycemic index (GI) in the management of diabetes is controversial, with contrasting recommendations around the world. We performed a meta-analysis of randomized controlled trials to determine whether low-GI diets, compared with conventional or high-GI diets, improved overall glycemic control in individuals with diabetes, as assessed by reduced HbA1c or fructosamine levels.

RESEARCH DESIGN AND METHODS—Literature searches identified 14 studies, comprising 356 subjects, that met strict inclusion criteria. All were randomized crossover or parallel experimental design of 12 days’ to 12 months’ duration (mean 10 weeks) with modification of at least two meals per day. Only 10 studies documented differences in postprandial glycemia on the two types of diet.

RESULTS—Low-GI diets reduced HbA1c by 0.43% points (CI 0.72–0.13) over and above that produced by high-GI diets. Taking both HbA1c and fructosamine data together and adjusting for baseline differences, glycated proteins were reduced 7.4% (8.8–6.0) more on the low-GI diet than on the high-GI diet. This result was stable and changed little if the data were unadjusted for baseline levels or excluded studies of short duration. Systematically taking out each study from the meta-analysis did not change the CIs.

CONCLUSIONS—Choosing low-GI foods in place of conventional or high-GI foods has a small but clinically useful effect on medium-term glycemic control in patients with diabetes. The incremental benefit is similar to that offered by pharmacological agents that also target postprandial hyperglycemia.

Footnotes

  • A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    See accompanying editorial, p. 2466.

    • Accepted March 19, 2002.
    • Received December 9, 2002.
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