Diabetes Care
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Published online April 17, 2007
Diabetes Care 30:1874-1876, 2007
DOI: 10.2337/dc06-2151
© 2007 by the American Diabetes Association
This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
dc06-2151v1
30/7/1874    most recent
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Amano, Y.
Right arrow Articles by Akabayashi, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Amano, Y.
Right arrow Articles by Akabayashi, A.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Clinical Care/Education/Nutrition
Brief Report

Glycemic Index–Based Nutritional Education Improves Blood Glucose Control in Japanese Adults

A randomized controlled trial

Yuki Amano, PHD1,2, Michiko Sugiyama, PHD3, Jung S. Lee, PHD1, Kiyoshi Kawakubo, MD, PHD4, Katsumi Mori, BSC1, Ann C. Tang, PHD5 and Akira Akabayashi, MD, PHD1

1 Department of Health Promotion Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
2 Japan Society for the Promotion of Science, Tokyo, Japan
3 School of Nutrition and Dietetics, Kanagawa University of Human Services, Kanagawa, Japan
4 Department of Food Sciences and Nutrition, Kyoritsu Women's University, Tokyo, Japan
5 Department of Medical Education, Tokyo Women's Medical University, Tokyo, Japan

Address correspondence and reprint requests to Dr. Yuki Amano, Department of Health Promotion Sciences, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. E-mail: yk-amano{at}umin.ac.jp

Abbreviations: FPG, fasting plasma glucose • GI, glycemic index


   INTRODUCTION
TOP
 INTRODUCTION
RESEARCH DESIGN AND METHODS--
 RESULTS--
 CONCLUSIONS--
 References
 
A low–glycemic index (GI) diet is effective in lowering A1C in diabetic patients (1–3). However, most research is from Western countries, where potato and wheat are the main sources of carbohydrates. A GI-based nutrition education program, designed for people who consume white rice (a high-GI food) as the staple, has not yet been studied. We developed a low-GI dietary regimen based on Japanese foods. This study aimed to evaluate whether GI-based nutrition education improves blood glucose control more than a conventional nutrition education in participants with type 2 diabetes or impaired fasting glucose.


   RESEARCH DESIGN AND METHODS—
TOP
 INTRODUCTION
 RESEARCH DESIGN AND METHODS--
RESULTS--
 CONCLUSIONS--
 References
 
We conducted a 3-month, randomized, controlled, parallel-group trial. Participant inclusion criteria were as follows: 1) fasting plasma glucose (FPG) between 110 and 160 mg/dl or A1C between 5.8 and 8.0% (4) and 2) nonusage of any hypoglycemic drugs.

All participants attended one group session on conventional nutritional education at baseline. Each participant was then randomly assigned to either GI-based or conventional nutrition education; four individual sessions followed (2nd week and 1st, 2nd, and 3rd month).

Conventional nutritional education was based on the Japan Diabetes Society guidelines (4) and focused on lowering total energy intake, mainly by reducing fat intake or eliminating snacking. The GI-based nutrition education aimed to train participants to consume one-half or more of their daily carbohydrate intake from low-GI foods (1,5–7). Because the main determinant of dietary GI is the staple food (5,8), education focused on the selection of low-GI staple foods. Participants were instructed to combine the high-GI staple foods with vinegar (7,9–12), dairy products (7,13,14), or fermented foods such as yogurt and pickles (7,15) to reduce postprandial blood glucose spikes.

After a 12-h fasting, blood samples were collected and immediately refrigerated and transported for analyses to the Health Science Research Institute. Under the same condition, height, weight, and fat were assessed by stadiometer (YG200; Yagami) or bioelectric impedance (BF-616; Tanita) without shoes. Dietary intake was assessed with a 3-day dietary record. Dietary GI was calculated by a method we described previously (5). All analyses were performed using SAS (version 9.1; SAS Institute, Cary, NC). Baseline differences between groups were assessed by an unpaired t test. Changes in outcomes were assessed by repeated-measures two-way ANOVA. The statistical significance standard was 5%.


   RESULTS—
TOP
 INTRODUCTION
 RESEARCH DESIGN AND METHODS--
 RESULTS--
CONCLUSIONS--
 References
 
Of the 40 participants, 19 and 21 were placed in the GI and conventional groups, respectively. One from the conventional group withdrew in the first month. All of the 39 remaining participants attended all sessions, took all required measurements, and submitted all of their dietary records.

A1C improved more in the GI group than in the conventional group (Table 1). The average changes in A1C were –0.46 ± 0.33% in the GI group and –0.21 ± 0.43% in the conventional group, and the effect size due to intervention was –0.25 (95% CI –0.50 to –0.004).


View this table:
[in this window]
[in a new window]

  		Table 1— Metabolic parameters and dietary data over the 3-month period for the GI-based conventional nutritional education groups

 
FPG, total and LDL cholesterol, and body weight and fat decreased significantly in both groups. Carbohydrate from low-GI foods and combination of high-GI staple foods with vinegar or other foods increased more in the GI group than in the conventional group. In both groups, dietary GI, total energy, and cholesterol intake significantly decreased and dietary fiber intake significantly increased.


   CONCLUSIONS—
TOP
 INTRODUCTION
 RESEARCH DESIGN AND METHODS--
 RESULTS--
 CONCLUSIONS--
References
 
According to a Cochrane meta-analysis, dietary advice plus exercise is associated with a mean 0.9% decrease in A1C at 6 months among type 2 diabetic patients (16). For the general population, a 0.3% decrease in A1C may well have significant health benefits (17). Our findings showed a posteducation difference of 0.25% in reduced A1C between the groups, despite a solely nutritional education–based strategy and a short duration of the intervention. Participants in the GI group may have shown further reduction in A1C over a longer period.

This is the first study to develop a GI-based nutritional education program for individuals whose staple food is white rice. Although replacing white rice with low-GI staple foods can increase fat intake (5), the GI group decreased energy intake without increasing fat intake. Furthermore, dietary indexes related to GI significantly improved in the GI group, suggesting good adherence to the program.

Our findings did not show a significant difference in the change over time in FPG, insulin, lipid metabolism, or body weight between the groups. Many studies have shown that low-GI diets are associated with changes in glucose metabolism (5,18–20), lipid metabolism (5,20–23), and body weight or fat (24–28). However, the conclusions of these associations are controversial (2,3,29,30). Further research to elucidate these relationships is needed.

The major limitation of our study was its small sample size. This may explain the nonsignificant differences between the two groups in baseline values. To generalize the study findings, a larger sample is needed.

In conclusion, GI-based nutrition education is effective in improving blood glucose control in participants with type 2 diabetes or impaired fasting glucose. The GI-based nutritional education yielded good adherence and could be considered a useful tool.


   Acknowledgments
 
This study was supported by a grant from the Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists and by the Japan Dairy Association.


   Footnotes
 
Published ahead of print at http://care.diabetesjournals.org on 17 April 2007. DOI: 10.2337/dc06-2151.

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

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C Section 1734 solely to indicate this fact.

Received for publication October 19, 2006. Accepted for publication April 2, 2007.


   References
TOP
 INTRODUCTION
 RESEARCH DESIGN AND METHODS--
 RESULTS--
 CONCLUSIONS--
 References
 

  1. Brand-Miller J, Hayne S, Petocz P, Colagiuri S: Low-glycemic index diets in the management of diabetes: a meta-analysis of randomized controlled trials. Diabetes Care 26:2261–2267, 2003[Abstract/Free Full Text]
  2. Kelly S, Frost G, Whittaker V, Summerbell C: Low glycaemic index diets for coronary heart disease. Cochrane Database Syst Rev CD004467, 2004
  3. Opperman AM, Venter CS, Oosthuizen W, Thompson RL, Vorster HH: Meta-analysis of the health effects of using the glycaemic index in meal-planning. Br J Nutr 92:367–381, 2004[Medline]
  4. Japan Diabetes Society: Kagakuteki konkyo ni motoduku tonyobyo shinryo gaidorain (Scientifically-Based Diabetes Care Guidelines). Tokyo, Nankodo, 2004 [in Japanese]
  5. Amano Y, Kawakubo K, Lee JS, Tang AC, Sugiyama M, Mori K: Correlation between dietary glycemic index and cardiovascular disease risk factors among Japanese women. Eur J Clin Nutr 58:1472–1478, 2004[Medline]
  6. Sugiyama M, Amano Y, Wakaki Y, Tang AC: Glycemic response of Japanese foods. Foods Food Ingredients J 211:526–535, 2006
  7. Sugiyama M, Tang AC, Wakaki Y, Koyama W: Glycemic index of single and mixed meal foods among common Japanese foods with white rice as a reference food. Eur J Clin Nutr 57:743–752, 2003[Medline]
  8. Murakami K, Sasaki S, Takahashi Y, Okubo H, Hosoi Y, Horiguchi H, Oguma E, Kayama F: Dietary glycemic index and load in relation to metabolic risk factors in Japanese female farmers with traditional dietary habits. Am J Clin Nutr 83:1161–1169, 2006[Abstract/Free Full Text]
  9. Brighenti F, Castellani G, Benini L, Casiraghi MC, Leopardi E, Crovetti R, Testolin G: Effect of neutralized and native vinegar on blood glucose and acetate responses to a mixed meal in healthy subjects. Eur J Clin Nutr 49:242–247, 1995[Medline]
  10. Leeman M, Ostman E, Bjorck I: Vinegar dressing and cold storage of potatoes lowers postprandial glycaemic and insulinaemic responses in healthy subjects. Eur J Clin Nutr 59:1266–1271, 2005[Medline]
  11. Liljeberg H, Bjorck I: Delayed gastric emptying rate may explain improved glycaemia in healthy subjects to a starchy meal with added vinegar. Eur J Clin Nutr 52:368–371, 1998[Medline]
  12. Ostman E, Granfeldt Y, Persson L, Bjorck I: Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. Eur J Clin Nutr 59:983, 2005[Medline]
  13. Frid AH, Nilsson M, Holst JJ, Bjorck IME: Effect of whey on blood glucose and insulin responses to composite breakfast and lunch meals in type 2 diabetic subjects. Am J Clin Nutr 82:69–75, 2005[Abstract/Free Full Text]
  14. Gannon MC, Nuttall FQ, Krezowski PA, Billington CJ, Parker S: The serum insulin and plasma glucose responses to milk and fruit products in type 2 (non-insulin-dependent) diabetic patients. Diabetologia 29:784–791, 1986[Medline]
  15. Ostman EM, Liljeberg Elmstahl HGM, Bjorck IME: Inconsistency between glycemic and insulinemic responses to regular and fermented milk products. Am J Clin Nutr 74:96–100, 2001[Abstract/Free Full Text]
  16. Moore H, Summerbell C, Hooper L, Cruickshank K, Vyas A, Johnstone P, Ashton V, Kopelman P: Dietary advice for treatment of type 2 diabetes mellitus in adults. Cochrane Database Syst Rev CD004097, 2004
  17. Khaw K-T, Wareham N, Luben R, Bingham S, Oakes S, Welch A, Day N: Glycated haemoglobin, diabetes, and mortality in men in Norfolk cohort of European Prospective Investigation of Cancer and Nutrition (EPIC-Norfolk). BMJ 322:1–6, 2001[Abstract/Free Full Text]
  18. Wu T, Giovannucci E, Pischon T, Hankinson SE, Ma J, Rifai N, Rimm EB: Fructose, glycemic load, and quantity and quality of carbohydrate in relation to plasma C-peptide concentrations in US women. Am J Clin Nutr 80:1043–1049, 2004[Abstract/Free Full Text]
  19. McKeown NM, Meigs JB, Liu S, Saltzman E, Wilson PWF, Jacques PF: Carbohydrate nutrition, insulin resistance, and the prevalence of the metabolic syndrome in the Framingham offspring cohort. Diabetes Care 27:538–546, 2004[Abstract/Free Full Text]
  20. Buyken AE, Toeller M, Heitkamp G, Karamanos B, Rottiers R, Muggeo M, Fuller JH: Glycemic index in the diet of European outpatients with type 1 diabetes: relations to glycated hemoglobin and serum lipids. Am J Clin Nutr 73:574–581, 2001[Abstract/Free Full Text]
  21. Liu S, Manson JE, Stampfer MJ, Holmes MD, Hu FB, Hankinson SE, Willett WC: Dietary glycemic load assessed by food-frequency questionnaire in relation to plasma high-density-lipoprotein cholesterol and fasting plasma triacylglycerols in postmenopausal women. Am J Clin Nutr 73:560–566, 2001[Abstract/Free Full Text]
  22. Ford ES, Liu S: Glycemic index and serum high-density lipoprotein cholesterol concentration among US adults. Arch Intern Med 161:572–576, 2001[Abstract/Free Full Text]
  23. Frost G, Leeds AA, Dore CJ, Madeiros S, Brading S, Dornhorst A: Glycaemic index as a determinant of serum HDL-cholesterol concentration. Lancet 353:1045–1048, 1999[Medline]
  24. Slabber M, Barnard HC, Kuyl JM, Dannhauser A, Schall R: Effects of a low-insulin-response, energy-restricted diet on weight loss and plasma insulin concentrations in hyperinsulinemic obese females. Am J Clin Nutr 60:48–53, 1994[Abstract/Free Full Text]
  25. Spieth LE, Harnish JD, Lenders CM, Raezer LB, Pereira MA, Hangen SJ, Ludwig DS: A low-glycemic index diet in the treatment of pediatric obesity. Arch Pediatr Adolesc Med 154:947–951, 2000[Abstract/Free Full Text]
  26. Bouche C, Rizkalla SW, Luo J, Vidal H, Veronese A, Pacher N, Fouquet C, Lang V, Slama G: Five-week, low-glycemic index diet decreases total fat mass and improves plasma lipid profile in moderately overweight nondiabetic men. Diabetes Care 25:822–828, 2002[Abstract/Free Full Text]
  27. Ebbeling CB, Leidig MM, Sinclair KB, Seger-Shippee LG, Feldman HA, Ludwig DS: Effects of an ad libitum low-glycemic load diet on cardiovascular disease risk factors in obese young adults. Am J Clin Nutr 81:976–982, 2005[Abstract/Free Full Text]
  28. McMillan-Price J, Petocz P, Atkinson F, O'Neill K, Samman S, Steinbeck K, Caterson I, Brand-Miller J: Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial. Arch Intern Med 166:1466–1475, 2006[Abstract/Free Full Text]
  29. Ludwig DS: The glycemic index: physiological mechanisms relating to obesity, diabetes, and cardiovascular disease. JAMA 287:2414–2423, 2002[Abstract/Free Full Text]
  30. Mayer-Davis EJ, Dhawan A, Liese AD, Teff K, Schulz M: Towards understanding of glycaemic index and glycaemic load in habitual diet: associations with measures of glycaemia in the Insulin Resistance Atherosclerosis Study. Br J Nutr 95:397–405, 2006[Medline]

Add to CiteULike CiteULike   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?



This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
dc06-2151v1
30/7/1874    most recent
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Amano, Y.
Right arrow Articles by Akabayashi, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Amano, Y.
Right arrow Articles by Akabayashi, A.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Diabetes Diabetes Care Clinical Diabetes Diabetes Spectrum