Multiple carbohydrate transporters in the gut and performance. This subject refers to the gastrointestinal tract (GI) , which has a fundamental function with regard to sports performance, pWithout a well-functioning gastrointestinal (GI) system, nutrient delivery will be impaired, and a variety of GI symptoms may develop.
An interesting fact is that 30-50% of all athletes experience these gastrointestinal problems on a regular basis. The causes of these problems can occur due to dehydration and hot weather conditions or due to excessive intake of fiber, fats, proteins and highly concentrated carbohydrate solutions. These variables, in addition to causing various problems in the intestine, can impair performance.
With this, aiming at an improvement in the intestinal and performance during exercise, a nutritional intervention was guided, the intervention is based on the use of different carbohydrates during a test.
The Multiple Carbohydrate Transporters
A good carbohydrate transport done by multiple carbohydrate transporters, is vital for the supply of energy during exercise. Some evidence has shown that the delivery of carbohydrates is limited by the transport capacity of SGLT1 (Asken Jeukendrup 2011, Asken Jeukendrup 2014 and Asken Jeukendrup 2013
). SGLT1 is the protein responsible for transporting glucose from the intestinal lumen to enterocytes. This is vital for the absorption of glucose in the intestine.
With intake rates above 60-70 g of carbohydrates per hour (glucose, sucrose, maltodextrin, starch), exogenous oxidation of carbohydrates peaks around 60 g/h, even with the intake of 100 g/h there was no increase in carbohydrate oxidation rates. However, when fructose was combined with large amounts of glucose, carbohydrate oxidation rates exceeded 60 g/h.
Fructose is added because its intestinal absorption differs from glucose, it uses a transporter called GLUT-5. Thus, the use of fructose with glucose aims to avoid SGLT1 saturation, enabling a better absorption of carbohydrates and mitigating gastrointestinal problems.
Clinical practice
Current guidelines recommend a carbohydrate intake of 60g/h for modalities that last up to 2 hours. If the modality exceeds 2 hours, this intake can reach 90 g/h.
In the context where this intake reaches 90 grams, it is prudent to have the mixture of different sources of carbohydrates, such as: fructose and glucose or maltodextrin and fructodextrin. This combination enables an optimization of carbohydrate absorption and would attenuate gastrointestinal disorders, improving the performance of athletes.
Suggested reading:
Peculiarities of carbohydrates in endurance
Article: JEUKENDRUP, Asker E.. Training the Gut for Athletes. Sports Medicine, , v. 47, [S .L.]n. 1, pp. 101-110, mar. 2017.
Http://dx.doi.org/10.1007/s40279-017-0690-6
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