With the emergence of carbohydrate supplementation the last few years and thankfully, what appears to be the decline of “carbophobia,” there have been quite a few new products to hit the market to take advantage of this. Staples such as waxy maize, Vitargo, maltodextrin and the like have continued to grow in sales, but it is surprising that one of the best carbohydrate sources in the world of sports nutrition is still underutilized: highly branched cyclic dextrin.
Highly branched cyclic dextrin (also known as HBCD) is a relatively new “designer” carbohydrate. It’s a specific group of carbohydrate that is essentially six to eight molecules of glucose chemically bonded together in a ring shape. More specifically, these molecules are made from amylopectin that have been altered by enzymes to create cross bridges, creating the unique ring structure via denaturing of the original molecules. Interestingly, it is similar to chemical composition to maltodextrin, but the effects vary greatly. One of the main differentiating factors from a structural standpoint is that while they share the same molecule count, the aforementioned maltodextrin is arranged in a linear (straight) fashion rather than the ring formation that is found in HBCD. This ring structure gives HBCD the unique benefits compared to other carbohydrate supplements when it comes to osmolality and gastric emptying (which we will delve into shortly).
HOW IT FUELS TRAINING
The idea behind HBCD and other carbohydrate supplements, at the core, is to provide a steady source of glucose to fuel and sustain training sessions, promote muscle growth— and, of course, prevent muscle breakdown. Ideally, carbohydrates that are easily broken down and absorbed should be used for this purpose, but the problem with many simple carbs is that they also cause an insulin response. This is great for post-workout— however, during a workout, the problem is that these high-glycemic carbs causing the insulin spike also lead to hypoglycemia, leading to a mid-workout crash.
The other caveat of most simple carbs is that they also have a high osmolality, whereas HBCD has a very low osmolality. Osmolality is the total number of molecules in a given solute in a kilogram of solvent, so the higher the osmolality simply means that there are a lot of molecules in the given solution. This comes into play with carbohydrates (solute), as when they are put into solvent, they of course break down. For example, if you take traditional sucrose, which is a combination of glucose and fructose, and put 100,000 molecules worth into solution, it will break down into 100,000 glucose molecules and 100,000 fructose molecules— meaning it now has 200,000 molecules in solution. HBCD, due to its high molecular weight, has digestive acid resistance, resulting in low osmolality.
Low osmolality is crucial, as the higher the osmolality, the slower the rate of gastric emptying will be. Most simple carbohydrates will not only cause an insulin spike, but with their high osmolality, will be held up in the stomach to be broken down— leading to a bloated feeling in the stomach. When they do finally release into the small intestine, this carb “bolus” causes the aforementioned insulin spike. HBCD, on the other hand, with low osmolality, passes easily through the stomach into the small intestine for uptake in a rapid but steady rate. The secret to the steady release once again lies in the structure: they are interlinked in such a nature that it takes longer to break down the glucose bonds, avoiding the insulin spike. Easily digested, so there’s no bloating and no insulin spike that can cause a mid-workout crash— you’ve got the best of both worlds.
With the osmolality in mind, one main question is, if you decide to incorporate HBCD: What should the dosage be? Although not ideal, your intra-workout HBCD consumption could be up to 50 percent of your daily carb total, though a much smaller percentage is typical. This comes down to personal preference and individual macronutrient needs. A good starting number is 25-50 grams, depending on training intensity and lean body mass. Another thing to note is that keeping the mixture in higher water content keeps the solution lower in overall osmolality.
Not using enough water will result in a hyper-osmolality solution and can cause dumping syndrome, a nasty potential side effect. This is caused because the hyper-osmolality solution is higher than your blood serum (for reference, normal serum is roughly a 15% solution) and for it to work properly, the solution needs to be lower than the serum level. As stated earlier, a starting dosage of 25-50 grams of HBCD and mixed in 28 ounces (a full blender bottle) of water is a nice sweet spot.
Last but not least, you can buy HBCD by itself in bulk, or there are a number of pre-made products on the market today aimed at intra-workout nutrition. If you opt for the bulk version, you can more easily customize your mixture. A few great items to pair with it for complete intra-workout coverage include BCAA or even a casein hydrosylate such as PeptoPro for a complete intra-workout formula that leaves the amount of each ingredient up to the individual.
So whether your goal is to build muscle, aid in recovery for your next training session or to improve endurance, HBCD is a supplement well worth the investment. With many studies already completed and more underway attesting to its benefits and ability to increase performance, clearly the future of carbs has already arrived … now it’s a matter of it getting the attention it deserves.