Is erythritol harmful to the heart and blood vessels?

Plenty of headlines about the sugar substitute erythritol have already been seen in the media: the Berliner Kurier, for instance, reported on a “shock study” suggesting that zero drinks could cause heart attacks and strokes. In Stern you could read that the “sugar substitute erythritol could increase the risk of heart attack and stroke”, and the Frankfurter Rundschau wrote: “Thrombosis: is the risk rising because of the popular sugar substitute erythritol?”

So there was a good deal of rustling in the press, and many users of this popular, practically calorie-free and carbohydrate-free sugar substitute were deeply worried and unsure whether they should go on eating it. Reason enough to take a look at the original study for once and see what critical doctors and scientists have to say about it.

The new study in the renowned journal Nature Medicine investigated whether there is a connection between the concentration of the sugar alcohol erythritol in the blood and heart attacks and strokes. To this end, various sugar alcohols and other substances in the blood were first measured in a good 1,100 randomly selected people (an “untargeted” analysis). In doing so it was found that as the erythritol concentration in the blood rose, the risk of suffering a heart attack or a stroke, or of dying from one, rose as well. At the highest concentrations it was clearly (significantly) increased.

Next, the research team looked specifically for connections between heart and vascular diseases and the amount of erythritol in the blood among around 2,100 US American and 800 European heart and vascular patients (!). Here too they found what they were looking for: the relative risk of the diseases named was roughly doubled with the largest amount of erythritol in the blood compared with the smallest amount. Risks increased to that extent should certainly make people sit up and should prompt further research. They do not, however, allow any conclusions about cause and effect.

In addition there is the following: we know from earlier studies that high amounts of erythritol in the blood point to metabolic disorders, that they represent a kind of early warning system. Accordingly, the erythritol in the blood would not be a cause, but a kind of warning light for the health of the heart and blood vessels. It is a little like the storks and the birth rate: as the stork population fell, birth rates in Germany fell years ago. That does not mean, though, that fewer children are born BECAUSE there are fewer storks to bring them 😉

Back to the study: next, laboratory studies with human blood preparations and studies with mice were carried out. These showed that “normal” amounts of erythritol in the blood stimulate processes which can lead to the clumping of the blood and to the formation of thromboses (blood clots). Both heart attacks and strokes can arise from “stickier” blood and from thromboses. That too should give us pause for thought. Nevertheless, such experimental tests are quite far removed from the processes in an intact human organism.

Last of all, eight healthy test subjects were given 30 g of erythritol in 300 millilitres of water, which they had to drink up on an empty stomach within two minutes. 30 g of erythritol corresponds roughly to what US Americans consume per day if they are among the frequent users of the sweetener. And anyone who knocks back diet drinks first thing in the morning on an empty stomach could reach similar amounts.

In any case, within 30 minutes this amount led to a thousandfold increase in the erythritol content of the blood. And it took around two days until the fasting values were reached again. The erythritol values were clearly above those which had led to an increased tendency to clump in the laboratory and animal studies.

The study cannot answer that. Because in the test subjects who had to down the erythritol drink on an empty stomach, no measurement was taken of whether their blood clotting had changed in any way. That is a shame, and you have to wonder why it was not done.

We also do not know why the erythritol values stayed so high for so long, whether that is “normal” and whether things are different on a low-carb or ketogenic diet. In that respect the authors of the study are absolutely right when they call for further research into erythritol and other sweeteners.

That does not justify sensationalist headlines along the lines of “popular sweetener makes the blood clump”, however. Because: the study is missing any (!) information at all about erythritol consumption. So we do not know at all how these people ate and whether, and if so how much, erythritol they took in. Presumably hardly any, because when the American study participants were asked about it, erythritol was still largely unknown.

Erythritol can also be formed in the body. Under certain circumstances the body makes it from grape sugar (glucose) itself. In what is known as the pentose phosphate pathway (PPP) it can convert various sugars into one another as required. It also appears possible that the body can use this pathway to remove excess glucose from the blood. That would help to explain why the PPP, and with it the body’s own formation of erythritol, is increased in situations such as oxidative stress, diabetes mellitus and obesity. All these situations are associated with an increased risk of heart attack and stroke. That shows once again that the erythritol is presumably only a “witness” to metabolic problems, but not the “culprit” that causes them.

Eating erythritol could even turn out to be favourable for the blood vessels. This is suggested by a study with people with type 2 diabetes in whom an improvement in vascular health was seen after four weeks of erythritol consumption (3 x 12 g per day). In other words: increased erythritol values in the blood could also represent an adaptive or protective reaction of the body. But that has not been proven either. Be that as it may: the long-term effects of a chronic (high) intake of erythritol have to be researched in further studies.

• It cannot make any statements about erythritol consumption, because that was not asked about.
  Only the amounts in the blood were measured, and those may have been formed in the body itself.
• Erythritol in the blood is regarded as a marker for metabolic disorders such as metabolic syndrome. Nobody can currently say whether increased erythritol values are a cause of it or a consequence of it, or even a protection against it.
• Nor can it be said whether increased erythritol values in the blood actually caused the risks to the heart and blood vessels observed in this study.

Should you now stop using erythritol? No, you do not need to. The substance with the E number 968 is approved and is regarded as safe. There are, however, hardly any long-term investigations into a possible influence on the human cardiovascular system.

In the meantime we should simply not overdo it, as with all treats. Why? You are sure to know the sentence from Paracelsus, the famous physician who already knew in the 16th century: all things are poison, and it is only the dose that decides whether a thing is a poison. That means: a little erythritol here and there in your tea or in a dessert or a cake, or a few Foodpunk pralines, that is completely fine even after this study. But anyone who eats mainly or predominantly sweet things, even if it is erythritol and however “keto” it may be, is not doing everything right. So: it is best to enjoy sweet things consciously, not in huge amounts but in moderation.