Glico’s cyclic dextrin may outperform conventional carbs for swimming endurance: Human data
Data published in Food Science and Technology Research indicated that swimmers consuming the highly branched cyclic dextrin (HBCD, the functional component of Glico’s Cluster Dextrin) were able to perform at optimum output for 70% longer than those consuming glucose or water.
The cyclic dextrin group was also found to have higher plasma glucose prior to swimming, suggesting that the ingredient may help to sustain glucose levels more consistently and effectively than typical endurance supplementation using carbohydrate delivered by maltose, sucrose, or glucose.
“The ingestion of HBCD resulted in a significant increase in the time to exhaustion. Indeed, the higher lactate level after 90% VO2max swimming in the HBCD trial suggested that the subjects oxidized greater amounts of CHO to yield energy following HBCD intake, compared to glucose or water intake,” wrote the authors. “It has been demonstrated that blood glucose levels are important during exercise, especially at the final stage of a prolonged exercise routine.
“In our study, the differences in time to exhaustion between the HBCD and control trials could be attributed to the relatively high blood glucose level in the HBCD trial.”
The ingredient
The ingredient is said to have three primary attributes: high solubility, fast gastric emptying time, and its ability to enhance stamina by managing blood glucose, said Glico in a release. The high-molecular weight and narrow molecular weight distribution also allow it to swiftly exit the upper gastric tract, according to the company, and this may also help reduce cramping and bloating that may be experienced with other carbohydrate sources.
Ezaki Glico produces Cluster Dextrin using a proprietary enzyme derivation process to yield a cluster-structured glucose polymer.
A spokesperson for the company previously told us that the ingredient can be used in both foods and dietary supplements and it is already included in sports nutrition products in the US.
Study details
For the new paper in Food Science and Technology Research, the researchers performed three discrete test trials one week apart. For each trial swimmers were randomly assigned to receive either glucose or water or cyclic dextrin. The swimmers then carried out 10 intermittent swimming trials, beginning with 5 minutes of swimming at 75% VO2max, followed by a 3 minute rest, and subsequently an all-out effort at 90% VO2max to the point of exhaustion. Trials were conducted in a countercurrent water machine, and so exhaustion was indicated by the swimmer’s forward movement being reversed one full meter by the current.
The results indicated that the cyclic dextrin group outperformed swimmers in the other two groups.
“HBCD, a type of maltodextrin with a narrow molecular weight distribution, was proposed to enhance endurance performance in elite athletes, likely by maintaining relatively high blood glucose levels without the negative effects of low-molecular weight carbohydrate,” concluded the researchers.
Commenting on the ingredients potential benefits, Glico noted that the cyclic dextrin’s very low osmolality and swift gastric emptying time affects water absorption in the small intestine, and hydration during athletic activity.
“Cluster Dextrin HBCD goes to the small intestine rapidly, and there distinguishes itself from glucose supplementation in its maintenance of blood glucose levels, which have been shown to be especially important during the final stages of an exercise routine,” said the company.
Beyond sports
Glico has also investigated the potential of the ingredient beyond enhancing endurance with internal data indicating that Cluster Dextrin may also improve flavors by masking bitterness, reducing acidity, and helping maintain their aromas longer.
These features enhance its applicability for sports nutrition drinks and formulas, said the company, since branched-chain amino acids (BCAA) and citric acid, mainstays of many sports nutrition products, impart flavors that detrimentally affect the palatability of the product. “In Japan, Glico uses Cluster Dextrin in its own Citric Acid & BCAA sports nutrition product to mask the acidity of the former and tame the bitterness of the latter, heightening its flavor appeal,” said the company.
“A great deal of the Cluster Dextrin Glico produces is used in Japan for modifying flavor,” it added.
Data from a ten person tasting panel indicated that adding the Cluster Dextrin ingredient at a level of 2% to a beverage containing BCAA (1.6%) and citric acid (0.75%) significantly improved the drinkability of the product, added the company.
Source: Food Science and Technology Research
Volume 21, Number 3, Pages 499-502, doi: 10.3136/fstr.21.499
“Evaluation of Exercise Performance with the Intake of Highly Branched Cyclic Dextrin in Athletes”
Authors: T. Shiraki, T. Kometani, K. Yoshitani, H. Takata, T. Nomura
