Cluster Dextrin, also known as highly branched cyclic dextrin (HBCD), has recently become a popular component of many sports nutrition products (e.g. Skratch Superfuel which we just reviewed) due to its ability to provide a high amount of carbohydrate in a low osmolality solution. These properties make it appealing for use before, during, and after workouts when carbohydrate availability is key.
HBCD is made from the starches in waxy corn and the structure of HBCD is linked chains of glucose with a cyclic structure on one end of the molecule and the branched chains on the other end.
Athletes may choose to utilize HBCD pre-workout when there is little time to ingest high amounts of carbohydrate from food or when GI tolerance of high carbohydrate meals is a concern. During exercise, HBCD can provide carbohydrate at high rates (e.g. > 60 g/h) while also providing hydration. The low osmolality means high carb demands may be met with enhanced delivery (faster gastric emptying and absorption of carbohydrate). Typically, when high carbohydrate rates are ingested (60-120 g/h), it’s recommended that multiple transportable carbohydrates (e.g. maltodextrin and fructose) are ingested to facilitate carbohydrate absorption and utilization. It’s not yet clear what the tolerance level of HBCD alone would be at ingestion rates of 90-120 g/h at various intensities and in varying environments. Fortunately, there are products that contain both HBCD and fructose to offer multiple transportable carbs in a single product. Due to its low osmolality, this type of product may be an attractive fueling strategy for an athlete looking for ways to meet high carbohydrate demands through predominantly liquid sources.
So far, the research supporting HBCD is encouraging. However, further studies utilizing Cluster Dextrin in field based settings, at high ingestion rates, and with and without other carbohydrate sources is needed.
Wilburn, D., et al. (2021). Journal of Exercise and Nutrition, 4(3).
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