Glycemic Response Assessment of Three Watermelon (Citrullus lanatus) Cultivars in Healthy Adults: A Randomized Crossover Trial
Glycemic Response of Three Watermelon (Citrullus lanatus) Cultivars in Healthy Adults
DOI:
https://doi.org/10.54393/pbmj.v9i8.1421Keywords:
Watermelon, Citrullus lanatus, Glycemic Index, Glycemic Load, Postprandial GlucoseAbstract
The glycemic index (GI) values in nutritional databases for watermelon tend to be generalizable based on sugar content, yet vary among cultivars; however, postprandial glycemia and glucose response vary among individuals and even cultivars. Objectives: To compare postprandial glycemia, GI, and glycemic load (GL) after consumption of Charleston Gray, Crimson Sweet, and Sugar Baby cultivars of watermelon by healthy subjects. Methods: This study was conducted as a randomized crossover trial with blinded outcome assessment and analysis (participants could not be fully blinded) in which 20 healthy volunteers (10 male and 10 female subjects; age 22.1 ± 0.8 yr; body mass index 24.4 ± 3.2 kg/m²) underwent four fasted trials in random order: 25 g anhydrous glucose or a fixed 417 g portion of each watermelon cultivar (intended to provide 25 g of available carbohydrate). Capillary glucose was tested at 0, 30, 60, and 120 min. Simplified four-point sampling and a single glucose reference test were used. Exploratory GI estimates were calculated from incremental area under the curve (iAUC). Results: There was a difference in GI between the cultivars (F (2,38) = 8.42, p=0.001, partial eta-squared=0.31). The exploratory mean ± SD GI of Charleston Gray, Sugar Baby, and Crimson Sweet were 61.7 ± 41.2, 47.4 ± 35.0, and 31.4 ± 26.8, respectively; and the Friedman sensitivity analysis also confirmed that there was a cultivar effect (χ² (2) = 12.40, p=0.002). Conclusions: Crimson Sweet had the lowest response, while the three cultivars of watermelons had low GL levels in a practical portion of 150 g. GI and GL values are provisional (simplified sampling, single glucose reference, capillary measurement) and should not be generalized beyond young healthy adults or typical servings. Cultivar and size of portion should be taken into account when evaluating the glycemic response of watermelons.
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Copyright © 2026. The Authors. Published by CrossLinks International Publishers LLC, USA. This work is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0), Copyright of each article remains with its authors, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For comments editor@pakistanbmj.com
