 It's funny when you search for information about the low-calorie sweetener erythritol in the scientific literature. You stumble across papers like this, describing a use for erythritol that I had not imagined. But you think that's explosive? What about headlines like these? Erythritol associated with increased body fat in young adults. Metabolic dysfunction, coronary heart disease, heart failure, pre-diabetes, full-blown diabetes, and diabetic complications like kidney damage and blindness. But wait, I thought erythritol has been reported to be totally safe and even like have antioxidant properties. Let's take a closer look at these studies. Upon entering college, many young adults experienced weight gain, the dreaded freshman 15, which can start them off on the wrong course in life in terms of developing chronic illness. But not all freshmen do, so researchers wanted to try to tease out why some gained weight and others didn't. So on one of their first days at school, a bunch of students got their blood drawn and then nine months later were reweight and got more blood taken. About a quarter of the students maintained a stable weight, but the other three quarters gained, in average, about 9 pounds. Then they did something interesting. They pulled the blood of all those who remained stable and compared that to the collection of blood from all the gainers to see if they could pick out any differences. And the ones that gained weight had significantly higher levels of erythritol in their blood and not just a little, 15 times higher levels. Those found to have poor blood sugar control had 21 times higher blood erythritol levels. And same thing with heart disease. What did people who developed heart disease have more in their blood than those who didn't? Erythritol. Same thing with diabetes and diabetic complications. OK, so what's going on? Is erythritol contributing to obesity and heart disease and diabetes, or is it just an innocent bystander? Maybe it's reverse causation, meaning instead of erythritol leading to more weight gain, maybe weight gain led to more erythritol. After all, who tends to go for the low-calorie sweeteners? But wait a second. In this study, for example, they took blood before and after a period of over 20 years. Was erythritol even around back then? The first blood draws were in the 80s, and erythritol wasn't approved until 2001. Same thing with the heart disease study. The blood samples were taken in the late 80s, so the presence of erythritol in their blood cannot be explained by consumption of erythritol as a sugar replacement. So wait, how did they end up with so much erythritol in their system? Their own body made it. We know that your body can take excess blood sugar and convert it into erythritol. If you give people radioactively labeled sugar within two hours, radioactively labeled erythritol shows up in your blood. It turns out erythritol is a pentose-phosphate pathway metabolite, meaning that's the pathway by which blood sugar is converted into erythritol. And the pentose-phosphate pathway is a protective pathway. It's a way your body disposes of excess blood sugar by trying to convert the sugar into other things to bring down blood sugar levels. So having erythritol in your system seems to be a consequence of too high sugars, not the cause. So no wonder erythritol is associated with diabetes. That may be just like saying high blood sugar levels are associated with high blood sugar levels, and high blood sugars are also associated with obesity and heart disease. In fact, erythritol synthesis could be an adaptive mechanism to counter the oxidative stress induced by obesity and high blood glucose. In other words, not just a way to reduce blood sugar, but since erythritol can act as an antioxidant, maybe your body is making it specifically to help sop up the mess. The bottom line is there's no studies linking the consumption of erythritol to any disease outcomes. But the flip side of that is, yeah, the studies that have been done on erythritol to show it to be relatively innocuous and possibly beneficial, but the effects of chronic erythritol consumption have not been evaluated either way. That's where the science was until 2023, when a prestigious lab out of Cleveland Clinic found increased clonics susceptibility in human blood in a test tube and mouse blood in a mouse artery. That was at blood concentrations like 45 micromoles or even 290, but have people chug two tablespoons of the stuff and erythritol blood levels jump up into the thousands within a matter of minutes. And so until we have clinical studies exonerating the stuff, I would recommend people to stay away from erythritol.