Not all sugar is the same. Different carbohydrates can vary in terms of their structure, digestion, and the speed at which glucose appears in the blood.
An interesting example of this is isomaltulose.
Like sucrose, isomaltulose consists of glucose and fructose. The difference lies in the chemical bond between the two molecules. This bond is broken down more slowly in the digestive tract.
A particularly interesting difference
There is an authorized health claim for isomaltulose:
Consumption of foods/drinks containing isomaltulose instead of other sugars induces a lower blood glucose rise after their consumption compared to sugar-containing foods/drinks.
A prerequisite for this is that the legal conditions for the replacement of other sugars are met. This is remarkable because it is not just a theoretical nutritional consideration, but an explicitly authorized health claim.
What current research is also investigating
In 2025, a randomized crossover study with 15 older adults with metabolic syndrome was published. On different test days, the participants received either 50 g of isomaltulose or 50 g of sucrose. In addition to glucose and insulin, the researchers also examined, among other things, the gut hormones GLP-1 and PYY.
A slower rise in glucose was observed after isomaltulose consumption. At the same time, various gut hormone responses differed compared to sucrose.
Of particular interest was the question of whether the type of carbohydrate previously consumed also influences the metabolic response to a subsequent meal – the so-called "second-meal effect."
GLP-1: interesting, but easy to misunderstand
GLP-1 has become a major focus of public attention due to modern medications. A clear distinction must be made here:
Isomaltulose is not a GLP-1 medication and does not act like a GLP-1 receptor agonist.
The study examined natural hormonal reactions of the digestive system after the consumption of different types of sugar. Therefore, no conclusions regarding weight loss, diabetes treatment, or a drug-like effect should be drawn from the measured changes in GLP-1 or PYY.
Small study, interesting physiology
With 15 people, the study was small. Furthermore, short-term metabolic responses were measured.
It is therefore more of a building block for understanding the specific digestive physiology of isomaltulose than evidence of long-term health effects.
Conclusion
The scientifically and legally clearest distinguishing feature of isomaltulose remains its influence on blood glucose rise compared to other types of sugar.
In addition, current research provides interesting insights into the different reactions of the digestive system to various carbohydrates.
Chemically and physiologically, sugar is simply not just sugar.
