Cyclodextrins are a new type of high performance carbohydrate. They have a series of properties that make them different from the rest of sport drinks.
The intake of nutrients around the workout has been gaining more and more relevance regarding the performance of athletes.
Some authors1 openly claim that the moment they choose to take supplementation is even more important than the total daily amount.
Personally, I think that the timing (moment when we eat food or take a supplement) is important for the elderly. In fact, less meals with more protein content have more benefits for the muscles2.
The moment we choose to take protein is less important for young people and athletes. Obviously, a pre or post-workout protein will increase the synthesis of in-muscle protein slightly. Even taking a protein before sleeping stimulates the retention of nitrogen in the body.
The situation changes radically when we talk about the timing of carbohydrates. As many of you already know, we either use glucose or fatty acids as energy (burn carbs or fats) during a workout session.
When the intensity is low, we mainly use fatty acids. As the intensity increases (and therefore the VO2max) the body will use glucose through a process called glycogenolysis.
Lambert et al. Graphic. Unlike what most people think, the use of glucose is not lineal. Rather, its use increases sharply when we reach a certain intensity.
High intensity VS Low intensity
It is almost impossible to know what is the factor that limits a drop in the performance in exercises where we use both glucose and fatty acids.
This happens because we do not know from which pathway does the energy come from. Said energy is scientifically known as ATP or adenosin triphosphate.
However, a worse glycolytic metabolism (use of glucose with low oxygen) results in a worse performance during high intensity exercises.
It goes without saying that the carb supply in the diet will affect the amount of glucose that we use. I develop this issue in more depth in another article. If we eat more carbs, we will use more glucose as energy. Therefore, we will enhance our performance during high intensity sports.
- This type of diet will not affect low intensity and long sports (e.g. marathons), since the fatty acids will provide the energy.
- However, it will be counterproductive for explosive or high intensity sports. This is due to the fact that the body will lower the production of lactate without enough glucose, as shown in the next image4.
As we can see, a low-carb diet lowers the production of lactate significantly
Performance expressed in minutes. Those who increase the intake of carbohydrates will further enhance their performance.
Unlike exercises like jogging or swimming where the muscle contraction is intermittent, weightlifting involves a great muscle contraction, which reduces the levels of glycogen significantly. In fact, some studies5 show how 6 sets with 12 reps produce a drop of glycogen in a 38%.
What is a cyclodextrin and how does it work?
Cyclodextrins are obtained from the enzymatic breakdown of starch. This process results in a product with a toroidal form (cone-shaped structure with a central cavity).
Even though they have been discovered recently, pharmacists know cyclodextrins really well already. Actually, they use them in barely soluble drugs (hydrophobic compounds).
But I know that you are mainly interested in its effect as an ergogenic support, so I will try to be as concise as possible.
Structure of a cyclodextrin. Source9
Properties of Cyclodextrins
Cyclodextrins dissolve more easily in water. This is partly due to their -OH (alcohol groups) which are located in the external part of its structure. This means that they will need a relatively low amount of water to dissolve properly.
This is extremely important in sport drinks. Otherwise, a lot of liquid during a workout or competition can delay the gastric emptying. Moreover, it can increase the feeling of being bloated, nausea, or affect the sodium levels (even though there is not concluding evidence for the latter).
A cyclodextrin is a substance with a low osmotic pressure.
Unlike other carbohydrates, these features shorten the gastric emptying process.
As the osmotic pressure increases, the time it takes to go through the digestive tract increases as well
Quick gastric emptying
The absorption will increase by shortening the time it takes to reach the intestine. That is also why it produces a great insulin and glucose peak in the blood. But when we compare a drink with cyclodextrin and another with glucose6, we will get the following result:
Unlike glucose, the cyclodextrin produces lower insulin and glucose peaks
As I mentioned previously, the gastric emptying is one of the most important factors for athletes. Most athletes complain about gastrointestinal problems caused by drinks or gels (specially those who are not used to train for several ours), which will hinder the performance.
This is why many experts have studied this topic in depth7, looking for a relation between the gastric emptying and gastrointestinal problems. When we compare several drinks with carbohydrates, we will get similar results to what we have previously seen:
Cyclodextrins have almost the same gastric emptying than water:
This lower time in the digestive tract, apart from resulting in a better digestion, reduces the side effects of consuming intra-workout carbohydrates, such as flatulence or belching:
Graphic on the left. Flatulence during the trial. Graphic on the right. Amount of belching. The subjects that were given cyclodextrin barely experienced said effects
Cyclodextrins VS Other Carbs
If you still remember the previous description of a cyclodextrin, I told you that it was produced due to an enzymatic breakdown of starch. Those who know about supplementation will also know that this is the same process to obtain amylopectin.
However, if we compare a drink containing cyclodextrin and another containing amylopectin, the results are different.
This was proven in a study8 in which they divided 24 healthy individuals between 25-39 years in two different groups. The A group was given a drink with 15g of cyclodextrin and the B group would drink one with amylopectin. It was a double blind study (neither the subjects nor the researchers knew what each individual was taking to avoid subjective results). A sweetened was added so that both had a similar flavor.
The training consisted in 30 minutes at a 40% of their VO2max and 90 minutes at a 60%, which resulted in a 2 hour workout. The result was the following:
The rating of perceived exertion (RPE and reflected through the Borg scale) was lower in the group that consumed the cyclodextrin
The researchers stated:
“The mechanism that is in charge of suppressing the increase of RPE during the workout after taking HBCD is not clear, but it could be related to the ability of cyclodextrin to supply energy and to its shorter gastric emptying”
In my opinion, cyclodextrins help most athletes, since their benefits reach mainly to groups. On the one hand, we have the benefits for athletes who perform long duration exercises, since it reduces the gastrointestinal problems and side effects that are experience in different sport drinks.
On the other hand, for athletes who perform anaerobic exercises such as sprints or weightlifting, since they encourage the use of glucose by the cells in a shorter period of time than the rest of carbs, without increasing the levels of insulin significantly.
- Timing of creatine or protein supplementation and resistance training in the elderly.Darren G. Candow and Philip D. Chilibeck
- Postprandial muscle protein synthesis is higher after a high whey protein, leucine-enriched supplement than after a dairy-like product in healthy older people: a randomized controlled trial.Yvette C Luiking12, Nicolaas EP Deutz2, Robert G Memelink1, Sjors Verlaan1 and Robert R Wolfe3*
- Nutrient timing revisited: is there a post-exercise anabolic window? Alan Albert Aragon and Brad Jon Schoenfeld
- Diet composition and performance of high intensity.R J Maughan, P.L. Greenhaf
- Muscle glycogenolysis during differing intensities of weight-resistance exercise.Robergs RA1, Pearson DR, Costill DL, Fink WJ, Pascoe DD, Benedict MA, Lambert CP, Zachweija JJ.
- Enhancement of swimming endurance in mice by highly branched cyclic dextrin.Takii H1, Ishihara K, Kometani T, Okada S, Fushiki T.
- A Sports Drink Gastrointestinal based on Highly Branched Cyclic Dextrin Generates Disorders in Untrained Men during Bicycle Exercise Few.Hiroshi TAKnl, Takashi KOMETANll, Takahisa NISHIMURA Takashi KURIK11 and Tohru FUSHIKI
- Effects of ingesting highly branched cyclic dextrin during endurance exercise on rating of perceived exertion and blood components associated with energy metabolism Takashi Furuyashikia, Hidenori Tanimotob, Yasuhiro Yokoyamac, Yasuyuki Kitaurad, Takashi Kurikia & Yoshiharu Shimomurad
- Enhanced Thermal Stability of Eugenol by Cyclodextrin Inclusion Complex Encapsulated in Electrospun Polymeric NanofibersFatma Kayaci , Yelda Ertas , and Tamer Uyar *