Extra ingredients in Sports drinks
Fructose
Fructose is added to sports drinks to increase the amount of energy that can be absorbed from a drink in a given amount of time. High 5 have publicised this concept with their "Energy Source" drinks which claim to improve performance by feeding the body with fructose at the same time as it absorbs glucose. The idea is that fructose, which uses different transporters to get into the epithelial cells that line the small intestine, can raise the maximal rate of energy absorption.
The mechanism:
The energy available to the body depends on the rate of stomach emptying, the amount that can be absorbed through glucose and fructose transporters and the speed with which fructose can be converted into glucose by the body.
The evidence:
Amino acids from protein digested in the gastrointestinal tract are transported to the liver where they are converted into energy sparing the proteins in the muscle tissues.. The evidence:
Protein
Protein is addded to sports drinks to increase recovery during and after exercise by preventing muscle proteins being broken down for fuel.
The mechanism: