How should the study results be understood?
Basically, it can be said that the third part of the study (the clinical study) showed that xylitol consumption increases the concentration of xylitol in the blood and that certain blood values change, which indicates increased platelet reactivity. This is a cause and effect relationship, real scientific evidence. If you eat/drink xylitol, your blood xylitol levels increase and your blood platelets become more reactive. However, the number of test subjects (ten participants) was very small.
On the other hand, an observational study, as in the first part of the investigation, can no Establish a cause-effect relationship. The study concludes that large amounts of xylitol are associated with a higher relative risk of serious cardiovascular events. However, this does not mean that xylitol causes these events (correlation/association is not causation).
Furthermore, the expression “that the risk of serious cardiac events increased by 57 percent with high blood levels of xylitol” must be correctly understood. Because the absolute risk is not described here. This would be the probability of a given event occurring for a single person at a given time. An absolute risk of 57 percent would mean that 57 out of every 100 people would be affected. However, the study presents relative risk – that is, how high the risk is for people with high xylitol levels of experiencing a serious cardinal event compared to people with low xylitol levels.
Relative risk testing is often used to determine how strong an observed association is (for example, between xylitol and heart disease risk). A prominent example of this in the history of health is smoking and lung cancer. A relative risk of 1 for smokers and 1 for non-smokers would mean that the danger would be the same for both. Any value above 1 means the risk is greater for a group. In fact, the relative risk of smokers of developing lung cancer compared to non-smokers is 20 to 1. This was found to be a very strong link in US tobacco industry trials.
What about xylitol and cardinal events? The relative risk for people with high blood levels of xylitol of experiencing such an event compared to people with lower blood levels of xylitol is 1.57 to 1.
Conclusion: Xylitol – yes or no?
The Cleveland Clinic study is an important foundation for discovering more about the health effects of sweeteners and sugar substitutes. Finally, xylitol has so-called “GRAS” status (“generally recognized as safe”) in the EU and the USA and can therefore be added to any food in unlimited quantities. The results showed that just one glass of a drink sweetened with xylitol has an effect on the behavior of platelets and, therefore, on blood clotting. However, the study was unable to define a dose-response relationship, that is, at what dose harmful levels of xylitol appear in the blood. The study authors also make this clear: more studies are needed to evaluate the long-term health effects of xylitol. However, they call on politicians to tighten legislation so that the quantities of sweeteners, sugar substitutes such as xylitol, used in food are declared.
For consumers, the results do not mean that people should throw away toothpaste or chewing gum if they contain xylitol. But especially people with an already increased risk of cardiovascular diseases (e.g. if they are overweight, have diabetes mellitus or smoke) or people with known blood clotting disorders (e.g. if they have a known factor V Leiden mutation or are take anticoagulants). Be aware that consuming products with high concentrations of xylitol may further increase your risk of heart attacks and strokes.
Anyone who consumes xylitol in their daily diet should alternate it with other sweeteners. However, the worst sweetener alternative is and continues to be sugar: many studies and Job Overview (link is external) have shown that increased sugar consumption is associated with many health problems. This is why the World Health Organization recommends consuming a maximum of 50 grams (about 12 teaspoons) of added sugar per day – it’s making a lot of noise in Germany at the moment official statistics (external link) almost 91 grams per day.