Effect of Coffee Consumption on the Glycemic Index of Khalas Dates Tested in Healthy and Diabetic Subjects

Background:The consumption of dates along with coffee is a deeply rooted habit in many societies. This study was designed to determine the effect of coffee consumption on the glycemic index of a common variety of dates (Khalas) tested in healthy subjects and individuals with type 2 diabetes mellitus.

Methods:Composition analysis was carried out for Khalas dates (Tamer stage) and the weight of the dates flesh equivalent to 50 g of available carbohydrate was calculated. The study subjects were thirteen healthy volunteers with a mean (± SD) age of 40.2 ± 6.7 years and ten participants with type 2 diabetes mellitus (controlled on lifestyle measures and/or metformin) with a mean HbA1c (± SD) of 6.6 ± (0.7 %) and a mean age (± SD) of 40.8 ± 5.7 years. Each subject was tested on five separate days with 50 g of glucose (on 3 occasions) and 50 g equivalent of available carbohydrates from the dates without coffee (on one occasion) and with coffee (on another occasion). Capillary glucose was measured in the healthy subjects at 0, 15, 30, 45, 60, 90 and 120 min and for the diabetics at 0, 30, 60, 90, 120, 150 and 180 min. The glycemic indices were determined as ratios of the incremental areas under the response curves for the dates alone/with coffee compared to glucose. Statistical analyses were performed using Student's t-tests.

Inclusion criteria

• required that those in the healthy group were healthy and in the diabetes group that their diabetes was controlled (HbA1c ≤8%) on diet with or without metformin

Exclusion criteria

• morbid obesity (BMI > 40 kg/m2)
• pre diabetes
• pregnancy
• presence of gastroenterological disorders
• alimentary tract surgery
• a history of gastroenteritis in the prior six months
• any alcohol intake
• smoking
• taking any medications (except metformin)
• poorly controlled diabetes (HbA1c > 8%) and the presence of acute or chronic diseases