Take Sugar Studies With a Grain of Salt, Part 1
A recent study says erythritol increases the risk of blood clotting. But does it?
By giving us the opinions of the uneducated, journalism keeps us in touch with the ignorance of the community. –Oscar Wilde
A study from the Cleveland Clinic saturated the news last year, terrifying people who use sugar substitutes. The study asserted that erythritol, a very popular natural sweetener, is associated with potentially deadly cardiovascular events.
Erythritol’s low glycemic index makes it easy for people to enjoy sweet foods without incurring high blood sugar. It’s an important sugar replacement for diabetics and a common component of a keto diet. But is it a killer?
The study analyzed more than 1,000 cardiac patients and found that those with the highest levels of erythritol in their blood also had the highest risk for heart attack and stroke. So, is it time to dump your erythritol? Before you decide, let’s dig into the story a bit. The truth is less frightening and more interesting than the headlines would suggest.
Surprisingly, given the breathless press coverage, the study doesn’t say anything about how much erythritol the patients consumed. We might assume that these people, many of whom were diabetic, were using some kind of sugar substitute. However, that information wasn’t in the data set they used.
Erythritol is produced by the body
But if the erythritol didn’t come from consumption, where did it come from? Several scientists, including Martha Field and colleagues at Cornell University, have shown that the human body actually makes erythritol on its own. This is called endogenous erythritol, and the amount produced tracks with metabolic disease. The sicker the patient, the greater the quantity of erythritol in their blood.
This home-grown erythritol is unrelated to its consumption. In fact, the body produces it in response to excess sugar, and it is a fruitful marker of cardiometabolic disease. In other words, the levels of erythritol found in these patients may be a consequence of not consuming erythritol, but sugar instead. Biology is deliriously complicated, so it’s not unusual for studies to clash. It typically indicates some interesting underlying science. It can be disconcerting for the layperson, but it’s gold for scientists—and science writers.
A diet high in sugar promotes the overgrowth of bacteria in the small intestine and can lead to a “leaky gut” where toxins and bacteria are able to enter the bloodstream and reach every organ in the body. Over time, this can morph into systemic inflammation, the root of many diseases, including metabolic syndrome, type 2 diabetes, heart disease, depression, dementia, and more. Bypassing sugar helps to keep your microbiota in good shape, and that, in turn, helps to keep your gut healthy and your mood upbeat—thus, the increasing use of sugar substitutes like erythritol.
The authors of the Cleveland Clinic study acknowledge that the body produces erythritol, yet they say, “We speculate that erythritol levels…originate from a combination of ingestion and endogenous production.” Unfortunately, the design of this study doesn’t warrant such speculation—the information simply isn’t in the data.
To address this shortcoming, another part of the study looked at what happens to the blood of test participants after consuming 30 grams of erythritol within two minutes. Blood clotting factors were increased, which is troublesome.
But there are several problems with this part of the study. First, there were only eight people involved, which makes the study underpowered. Second, 30 grams is a lot of erythritol to take at one sitting, far more than the average consumer uses in a day. Third, there were no control groups. There is an understandable urge to go with compelling stories, but small studies like this should be kept for internal use, not published in Nature. Better to wait until there is a larger, controlled study before you start to freak people out.
I’ll have more to say on this important subject next week, but for now, if you use erythritol or other natural sugar substitutes, don’t worry. There is far more evidence that natural sweeteners are perfectly safe, although some artificial sugars may be troublesome. Be sure to subscribe (it’s free!) and tell your friends and family about this newsletter. It could lift their health for years to come.
References
Witkowski, Marco, Ina Nemet, Hassan Alamri, Jennifer Wilcox, Nilaksh Gupta, Nisreen Nimer, Arash Haghikia, et al. “The Artificial Sweetener Erythritol and Cardiovascular Event Risk.” Nature Medicine, February 27, 2023, 1–9.
Ortiz, Semira, Doletha Szebenyi, and Martha Field. “Endogenous Synthesis of Erythritol, a Novel Biomarker of Weight Gain (P15-016-19).” Current Developments in Nutrition 3, no. Suppl 1 (June 13, 2019): nzz037.P15-016-19.
Ortiz, Semira R., and Martha S. Field. “Elevated Plasma and Urinary Erythritol Is a Biomarker of Excess Simple Carbohydrate Intake in Mice.” bioRxiv, December 4, 2022.
It's a shame, because the Cleveland Clinic is usually better than this.
Too many problems with the study. Small sample size and correlation is not causation.