November 8, 2013

Laura E. Forbes, Shauna M. Downs, Shawn N. Fraser, Sumit R. Majumdar, Geoff D. C. Ball, Ronald C. Plotnikoff, Paul D. Wozny, Brian D. Torrance, Linda J. McCargar, Richard Z. Lewanczuk, Jonathan M. McGavock

Originally Published in the CSEP member newsletter, Communiqué, November 2013

The high prevalence of obesity in Canadian youth has led to increasing concern about their risk of developing chronic diseases such as type 2 diabetes in the future. Reduced insulin sensitivity is one of the earliest manifestations of altered glucose metabolism and is a strong predictor of future diabetes risk. Dietary intake has been shown to influence insulin sensitivity in adults, however, few studies have been done to assess the link between diet and insulin sensitivity in youth. Examining which dietary factors are associated with insulin sensitivity may provide insight into appropriate targets for interventions to reduce the risk for type 2 diabetes.

The Healthy Hearts Prospective Study of Cardiometabolic Health in Youth is a school-based study that involves 14 schools in one school district encompassing five rural and urban communities within 80 km of Edmonton, Alberta. Data collected in 2007-2008 were used for this analysis. Youth aged 10-14 years were recruited and all data were collected in the school environment. Insulin sensitivity was measured non-invasively using a 13C glucose breath test; a test which assesses change in the 13CO2 content of the breath 90 minutes after ingestion of a beverage containing 13C-labelled glucose. Anthropometric data collected included measured height and weight. Dietary variables (glycemic index, glycemic load, fiber, magnesium, vegetable and fruit and fat intakes) were assessed using, a validated, web-based 24-hour recall tool.

In total, 378 students (60% girls, 40% boys) aged 12.1 ± 1.2 years were studied. Within this sample, 24% of youth were considered overweight or obese based on their BMI z-scores. Multiple regression analyses showed that students with higher BMI z-scores were more likely to have low insulin sensitivity scores. In addition, boys (but not girls) with high glycemic index diets were more likely to have lower insulin sensitivity scores. Other dietary factors were not associated with insulin sensitivity. These findings suggest that interventions that reduce BMI (in both sexes) and include a low glycemic index diet (particularly among boys) may improve insulin sensitivity in youth and possibly prevent the future development of type 2 diabetes.


Applied Physiology, Nutrition, and Metabolism, 2013, 38(3): 320-325, 10.1139/apnm-2012-0232

This article is a summary of an article published in Applied Physiology, Nutrition & Metabolism. If you intend citing any information in this article, please consult the original article and cite that source. This summary was written for the Canadian Society for Exercise Physiology and it has been reviewed by the CSEP Knowledge Transfer Committee.

The CSEP Knowledge Translation Committee supports the translation of research-based knowledge for the practical application of improving the health of Canadians through the publication of this article.