Medically Reviewed Article

Dr. Ravi Sishir Reddy

MBBS, MD (General Medicine) • Consultant Physician & Internist
15+ Years Clinical Experience • Vivekananda Hospital, Hyderabad

Internal Medicine Diabetes & Metabolic Diseases NABH Accredited Hospital

Last Reviewed

Mar 31, 2026

🏥 Vivekananda Hospital — NABH-Accredited, 100-Bed Multispecialty, Est. 1995 📋 Our Review Process

That "sugar-free" protein bar you had this morning, the zero-calorie energy drink at your desk, the keto ice cream you enjoy guilt-free every night. They all likely contain the same ingredient: erythritol. For years, this sugar substitute has been marketed as a perfectly safe alternative to sugar. But a groundbreaking new study from the University of Colorado Boulder has revealed a disturbing reality that could change how you look at every "sugar-free" label.

Researchers discovered that erythritol, at levels found in just a single serving of a sugar-free drink, can damage brain blood vessel cells, reduce the body's natural ability to break down blood clots, and constrict blood vessels in ways that significantly increase the risk of stroke. This is not a fringe study. It builds on earlier research involving 4,000 people that linked higher erythritol levels to heart attacks and strokes over a three-year period.

In this doctor-reviewed guide, we explain exactly what the research found, which products contain erythritol, how it damages your body, and what safer alternatives you can switch to today.

What Is Erythritol and Why Is It So Popular?

Erythritol is a sugar alcohol, a type of carbohydrate that occurs naturally in small amounts in fruits like grapes and watermelon. However, the erythritol in your food is not coming from fruit. It is industrially manufactured by fermenting corn using yeast, then crystallized into a white powder that looks and tastes remarkably like sugar.

It became a darling of the health food industry for several reasons. It has almost zero calories (0.2 calories per gram compared to sugar's 4 calories per gram). It does not spike blood sugar or insulin levels. It does not cause tooth decay. And it has about 80% of the sweetness of regular sugar with no bitter aftertaste, unlike many other artificial sweeteners.

The FDA approved erythritol in 2001, and since then it has found its way into hundreds of products marketed as "healthy," "keto-friendly," "diabetic-safe," and "zero sugar." Until recently, it was considered one of the safest sugar substitutes available. That assumption is now being seriously challenged.

What the New Study Actually Found

The study, published in the Journal of Applied Physiology by researchers at the University of Colorado Boulder's Integrative Vascular Biology Lab, went beyond simply observing a correlation. The researchers wanted to understand the mechanism: how exactly does erythritol increase cardiovascular and stroke risk?

They exposed human brain microvascular endothelial cells (the cells that line the tiny blood vessels in your brain and form part of the blood-brain barrier) to a concentration of erythritol equivalent to what you would get from drinking a single serving of a sugar-free beverage. The exposure lasted three hours.

The results were alarming across every measure they tested:

"Big picture, if your vessels are more constricted and your ability to break down blood clots is lowered, your risk of stroke goes up," said Auburn Berry, lead author and graduate researcher at the university. "Our research demonstrates not only that, but how erythritol has the potential to increase stroke risk."

Senior author Professor Christopher DeSouza noted that their study used only a single serving-size amount. For people who consume multiple servings of erythritol-containing products daily (which is common among keto dieters and diabetics), the cumulative impact could be significantly worse.

How Erythritol Damages Your Brain Blood Vessels

To understand why these findings are so concerning, you need to understand what the blood-brain barrier does and how erythritol disrupts it.

The Blood-Brain Barrier: Your Brain's Security System

Your brain is protected by a highly selective barrier formed by specialized endothelial cells lining the brain's blood vessels. This barrier allows nutrients and oxygen through while blocking harmful substances, pathogens, and toxins. When this barrier is compromised, the brain becomes vulnerable to inflammation, clotting, and stroke.

What Erythritol Does to This System

Step 1: Oxidative stress explosion. Erythritol triggers a 75% increase in free radicals within brain endothelial cells. While the cells attempt to fight back by producing more antioxidant enzymes (catalase and superoxide dismutase), these defences are overwhelmed. The free radicals remain elevated, damaging cell membranes, DNA, and proteins.

Step 2: Blood vessel constriction. Healthy blood vessels rely on a balance between nitric oxide (which relaxes and widens vessels) and endothelin-1 (which constricts them). Erythritol shifts this balance dramatically. It reduces nitric oxide production while simultaneously increasing endothelin-1. The result is blood vessels that stay dangerously constricted, reducing blood flow to the brain.

Step 3: Clot defence is disabled. Normally, when a blood clot forms in a brain vessel, your cells release a compound called tissue plasminogen activator (t-PA) that dissolves the clot before it can block the vessel and cause a stroke. Erythritol reduces t-PA production by approximately 25%, effectively disabling this critical safety mechanism. Clots that would normally be dissolved remain intact, free to block blood flow and trigger a stroke.

Common Products That Contain Erythritol

Erythritol is far more widespread than most people realise. It is not just in obvious "diet" products. Check the labels of these categories carefully:

Who Is Most at Risk?

While the research raises concerns for everyone who consumes erythritol, certain groups face heightened risk:

Safer Sweetener Alternatives

If you are looking to reduce sugar without the vascular risks associated with erythritol, several alternatives have better safety profiles based on current evidence:

What Should You Do Right Now?

Based on the current evidence, here are practical steps you can take today:

First, check your pantry and fridge. Read the ingredient labels of your protein bars, sugar-free drinks, keto snacks, chewing gum, and any product marketed as "sugar-free" or "zero calorie." Look for "erythritol" or "sugar alcohol" in the ingredients list.

Second, reduce consumption rather than panic. This research was conducted on cells in a laboratory. While the findings are concerning and supported by the earlier 4,000-person study, we do not yet have definitive proof from large-scale clinical trials in humans. The prudent approach is to reduce consumption, not to assume immediate danger from occasional use.

Third, switch to safer alternatives. If you are a daily consumer of erythritol-containing products (multiple servings per day), consider switching to stevia-based or monk fruit-based alternatives where possible.

Fourth, talk to your doctor. This is especially important if you have existing cardiovascular disease, diabetes, high blood pressure, or a history of stroke. Your doctor can help you assess your personal risk and suggest appropriate dietary changes.

Fifth, do not go back to sugar. The solution to erythritol concerns is not to return to excessive sugar consumption, which carries its own well-established risks for diabetes, heart disease, obesity, and inflammation. The goal is to find the safest middle ground for your individual health situation.