Cyclodextrin (HBCD)

Cyclic Dextrin (HBCD) is a high-molecular carbohydrate, which through enzymatic modification of starch, ensures rapid absorption and sustained energy release.

This article is part of the Complete Guide to Proper Nutrition — a fundamental guide from the expert team at Sport Zone.

What It Is

Cyclic dextrin, also known as Highly Branched Cyclic Dextrin (HBCD), is an innovative carbohydrate polymer resulting from the enzymatic degradation of starch (usually corn). This process creates a unique cyclic structure of the molecules, which gives them specific physicochemical properties that distinguish it from traditional carbohydrates like maltodextrin or dextrose. The molecular weight of HBCD is significantly higher than that of simple sugars, yet it retains its ability to dissolve easily in water.

The main characteristic of HBCD is its low osmolality in solution. Osmolality is a measure of the concentration of dissolved particles and directly affects the rate of gastric emptying. Solutions with low osmolality pass more quickly from the stomach into the small intestine, where absorption begins. This hydrophilic nature and unique structure allow HBCD to act as an energy "transport system," preventing stomach discomfort often associated with consuming highly concentrated sugar solutions.

How It Works

The mechanism of action of cyclic dextrin is based on several key aspects. Thanks to its complex yet stable cyclic structure and high molecular weight, HBCD has low osmolality when dissolved in water. This minimizes hydration changes in the stomach and facilitates the passage of fluid and nutrients from the stomach to the small intestine. Here's how this affects energy metabolism:

• Rapid Gastric Emptying: Low osmolality leads to faster passage of HBCD from the stomach to the small intestine, reducing the risk of stomach discomfort and bloating during exercise.
• Sustained Glucose Release: Despite its rapid entry into the bloodstream, HBCD is gradually broken down into glucose by enzymes in the small intestine, providing a stable and continuous supply of energy.
• Optimal Blood Sugar Maintenance: This controlled process prevents sharp spikes and drops in blood sugar and insulin levels, which are often observed when consuming simple sugars, thus maintaining more stable energy levels.
• Efficient Glycogen Replenishment: The continuous supply of glucose aids in the efficient replenishment of muscle and liver glycogen stores, which is essential for recovery after intense physical exertion and for preparation for subsequent training.

Why It's Important for Athletes

For athletes, HBCD represents a valuable energy source that can optimize performance and recovery. Its ability to provide a rapid yet sustained influx of glucose without stomach discomfort makes it a suitable choice for intra-workout or post-workout drinks. Observations show that athletes consuming HBCD can maintain higher blood glucose levels during prolonged exertion compared to those taking other carbohydrates, which helps delay fatigue. For example, studies on prolonged physical exertion indicate that a single dose of 0.5 – 1.0 grams of HBCD per kilogram of body weight, dissolved in a drink, can improve endurance and reduce the perceived effort.

Besides during the workout itself, HBCD also plays a key role in the recovery phase. Rapid and efficient replenishment of muscle glycogen is essential for accelerating recovery and preparing the body for subsequent exertion. Recommendations from leading sports organizations, such as the International Society of Sports Nutrition (ISSN), for carbohydrate intake after training range from 1.0 – 1.2 grams per kilogram of body weight in the first four hours post-exercise. Integrating HBCD into such protocols can facilitate achieving these goals by minimizing digestive stress and ensuring effective energy loading, supporting anabolic processes.

Related Terms

• Glycogen — The body's primary glucose store, which HBCD helps to efficiently replenish for energy.
• Maltodextrin — Another commonly used carbohydrate in sports nutrition, from which HBCD differs in its lower osmolality and smoother glucose release.
• Isomaltulose — A low glycemic index carbohydrate that, like HBCD, provides a more stable energy flow, but through a different mechanism of slow digestion.
• Anabolism — The process of tissue building, which is supported by adequate carbohydrate intake like HBCD after training, providing energy for recovery and growth.