Arabic coffee increases the glycemic index but not insulinemic index of dates

Objectives: To determine whether the glycemic index (GI) and insulinemic index (II) of dates could be altered by Arabic coffee consumption. Methods: This randomized cross-over study was conducted at the Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom from November 2009 to February 2010. Healthy subjects (5 males, 5 females) were recruited to the study. They were fed Khulas dates either with water, or with Arabic coffee. Plasma glucose and insulin responses were measured using standardized methods. Responses were compared with a pure glucose solution matched for available carbohydrate. The GI and II were calculated using standardized methods, and results were presented as means and standard error of mean. Glucose and insulin responses were compared using repeated measures analysis of variance. Results: The GI of dates was 55 +/- 6, which increased to 63 +/- 5 for dates consumed with Arabic coffee (p=0.08). No significant difference was observed between the II for dates, and the II of dates consumed with Arabic coffee (p=1.00). Conclusion: Arabic coffee consumption modestly increased the plasma glucose response of dates compared to that of dates consumed with water. Insulin levels were not significantly affected. The modestly higher glycemic response to dates in the presence of Arabic coffee indicates that this custom may be considered detrimental to health.