So far, the sweetener erythritol has been classified as harmless. But a recent study suggests that the sweetener could increase the risk of stroke and heart attack. Experts therefore recommend avoiding it.
Natural, tooth-friendly and virtually calorie-free: the sweetener erythritol has long been used in dozens of countries and in many diet foods as a sugar substitute. A study now indicates that the substance can significantly increase the risk of thrombosis - and thus the risk of heart attack and stroke. The research team writes that this is particularly worrying given that the sweetener is aimed at people with diabetes, obesity and cardiovascular diseases, for example, who are already particularly at risk.
The safety of the sugar substitute must be checked, warns the international team led by Stanley Hazen from the Cleveland Clinic in the journal "Nature Medicine". Thomas Eschenhagen from Hamburg University Hospital Eppendorf, who was not involved in the study, speaks of a "warning sign". "The study is extremely important because millions of people take this sweetener every day," says the pharmacologist, who is a member of the scientific advisory board of the German Heart Foundation.
Artificial sweeteners are increasingly being added to soft drinks and other foods, writes the team, which includes researchers from several German institutions such as the Berlin Charité. However, there was increasing evidence of undesirable side effects of such substances in general, including weight gain, insulin resistance, diabetes and cardiovascular problems.
Erythritol - also known as erythritol or E 968 - is a common sugar substitute that is not only found in diet drinks, but also in low-calorie ice cream or chocolate. The substance is hardly metabolized, excreted with the urine and is therefore considered to be almost calorie-free. The substance, which you can buy by the kilo on the internet, is also made by the body itself, albeit in very small amounts.
The European Food Safety Authority (EFSA) considers an addition of 1.6 percent to non-alcoholic beverages to be harmless - this corresponds to 16 grams of erythritol per liter. Even if such substances are classified as safe by the regulatory authorities, writes Hazen's team, little is actually known about their long-term effects. So far there have been no studies on the risk of thrombosis. The research team now specifically tested this.
Initially, data from almost 1,200 participants with an increased risk of cardiovascular disease provided a clear suspicion that high erythritol levels in the blood were frequently associated with heart attacks and strokes. Analyzes of two other large groups - a good 2,100 US citizens and more than 800 Europeans, also particularly at risk for cardiovascular diseases - confirmed this connection.
This was true even when risk factors of the participants were taken into account. In general, the risk of stroke and heart attack in those people with particularly high levels was about twice as high as in those with particularly low concentrations. This finding applied to both men and women and also to other subgroups, such as age or weight groups.
According to laboratory tests, the sweetener increases the accumulation, also known as aggregation, of blood platelets and the tendency for blood to clot. This increases the risk of occlusion of a blood vessel (thrombosis) and thus of circulatory disorders in the heart or in the brain. After consuming a typical erythritol-containing drink, the erythritol levels in the blood plasma of eight healthy subjects increased approximately 1000-fold for several hours and remained significantly elevated for a period of two days.
"Various evidence shows that elevated erythritol levels directly contribute to increased platelet reactivity and increased risk of thrombosis," the group writes. The long-term effects of artificial sweeteners in general and erythritol in particular on heart attack and stroke need to be reviewed, especially in people who are already at risk.
"Cardiovascular disease evolves over time, and heart disease is the leading cause of death worldwide," study leader Hazen said in a statement from the Cleveland Clinic. "We have to make sure that our food isn't a hidden contributor."
The Hamburg expert Eschenhagen speaks of a "convincing chain of arguments". Although one cannot completely rule out that hidden factors are responsible for the observed effect, the impressive data are conclusive. "Ingestion of this sweetener leads to enormous concentrations of erythritol in the blood, and over a longer period of time."
Stefan Kabisch from the German Center for Diabetes Research (DZD) at the Charité suspects that the risk found in high-risk patients can probably also be transferred to other people. "The publication is an important, long overdue stimulus for more intensive research into food additives that have already been approved, such as sweeteners," he emphasizes. However, it is still too early to issue a warning about such substances.
The nutritionist Hans Hauner from the Technical University of Munich (TUM) speaks of an "impressive data set that is explosive and should be taken seriously from a clinical perspective". But there are still open questions. "These and other questions on this topic pose an enormous challenge for science, which will certainly take years before hopefully there is clarity."
