When Zero-Sugar Isn't Quite What It Seems: A Closer Look at Sugar Substitutes
- Joyce Knieff, ND, LAc
- Jun 9
- 7 min read
Walk down any grocery aisle and the words on the labels almost write themselves. Zero sugar. No calories. Keto-friendly. Diet. For decades, the assumption built into all of that marketing has been that swapping out sugar for a sweetener was a free trade, with the calories gone and nothing meaningful taken on in their place. The newer research is starting to complicate that picture. A Medscape review in late May pulled together a body of evidence that has been building for the better part of a decade, and the headline is a genuine shift from the old assumption. Sugar substitutes are not metabolically neutral. Some of them appear to carry meaningful long-term costs.
TL;DR: New research suggests sugar substitutes aren't metabolically neutral. Some shift the gut microbiome or raise cardiovascular risk signals, so the better goal is lowering overall sweetness, not swapping one sweetener for another.
Key takeaways:
In a human trial, saccharin and sucralose shifted gut bacteria and impaired glucose tolerance.
A 100,000-person cohort tied higher sweetener intake to more cardiovascular and stroke events.
Erythritol, common in keto products, was linked to higher clotting and cardiac risk.
Stevia and monk fruit carry the most reassuring evidence so far.
What the research found
The Medscape piece pulled together findings from a few different lines of work, but the most important threads come from three primary studies worth reading directly. The first is a 2022 paper in Cell by Jotham Suez and colleagues at the Weizmann Institute of Science. They ran a randomized trial in 120 healthy adults, giving them either saccharin, sucralose, aspartame, stevia, glucose, or no supplement for two weeks at doses below the regulatory daily limits. Each of the four non-nutritive sweeteners changed participants' gut and oral microbiomes in distinct ways. Saccharin and sucralose specifically impaired glucose tolerance. When the researchers transferred gut bacteria from human responders into germ-free mice, the mice took on similar glucose responses. The mechanism wasn't just correlation. It traveled with the microbiome.
The second is a 2022 paper in BMJ by Charlotte Debras and the NutriNet-Santé team in France, which followed 103,388 adults over an average of about 9 years. Higher consumption of artificial sweeteners across all dietary sources was associated with a 9 percent higher risk of cardiovascular disease overall and an 18 percent higher risk of cerebrovascular events. Aspartame intake specifically tracked with higher stroke risk. Acesulfame potassium and sucralose tracked with higher coronary heart disease risk. This is observational data and cannot prove causation, but the cohort is large, the follow-up is long, and the signal is consistent.
The third is a 2023 paper in Nature Medicine by Marco Witkowski, Stanley Hazen, and colleagues at the Cleveland Clinic. They studied erythritol, the polyol sweetener marketed as metabolically inert and used heavily in keto and zero-sugar products. In three independent patient cohorts undergoing cardiac evaluation, the highest blood-erythritol quartile had roughly 1.8 to 2.2 times the risk of a major cardiovascular event over three years compared with the lowest quartile. In the laboratory, physiologically realistic erythritol levels increased platelet reactivity and clot formation. A small human ingestion study showed that a single serving raised plasma erythritol well above the threshold associated with platelet activation, and the elevation lasted for more than two days.
The picture across these studies has become hard to dismiss. The Medscape piece also notes that stevia, which is plant-derived from steviol glycosides, has the most favorable metabolic profile of the available options. The data on it are reassuring at this stage and short on long-term outcomes. The assessment is preliminary.
The bigger picture
The original case for non-nutritive sweeteners rested on a simple idea. If sugar drives weight gain, diabetes, and cardiovascular disease, then removing the sugar should remove some of the harm. The unstated assumption was that the sweetener replacing the sugar was inert. That assumption hasn't aged well across multiple research domains.
The gut microbiome is one of those domains. The community of bacteria that lives in the human intestinal tract is now understood to be involved in glucose handling, inflammatory tone, lipid metabolism, and signaling to the brain. When that community is shifted by a daily dietary input, the downstream effects show up in places that don't look connected on the surface. The Suez findings are important because they show this mechanism in humans, not just in mice, and they identify the microbiome as the route between the substance and the metabolic change.
The cardiovascular story is the other major thread. Erythritol's relationship with platelet activation, and the broader cohort findings on aspartame, sucralose, and acesulfame potassium, point at a vascular pathway that wasn't on anyone's radar when these sweeteners were approved for widespread use. The original safety assessments looked at cancer risk and short-term metabolism. They were not designed to capture the gut-microbial or platelet-activation pathways that more recent research has surfaced.
The naturopathic perspective
The deeper question that this body of work raises isn't really about sweeteners. It's about what the body recognizes as food. The human digestive system, the microbial communities that live in it, and the metabolic and immune systems they interact with all evolved with whole, recognizable foods carrying their fiber, water, micronutrients, and phytochemicals together. When a molecule is concentrated, stripped of its food matrix, or invented to mimic sweetness without supplying energy, the systems built to handle food can respond in unpredictable ways. The Suez microbiome data and the Witkowski platelet data are different versions of the same idea showing up in different tissues.
Whole-person care has tended to frame sweeteners the same way it frames any concentrated extract. They might be useful in specific clinical situations for short periods of time. They aren't a substitute for the underlying work, which is reducing the body's overall daily sweetness exposure so the system can come back to baseline. The Medscape clinical note echoes this: taste thresholds adapt within a few weeks of eating less sugar. The body is built to recalibrate. The supplement aisle and the diet-food shelf often work against that recalibration by keeping the sweet signal turned up.
There are also clinical conversations that warrant a careful look at sweetener use rather than a blanket recommendation. For people with diabetes, sweetener substitution is sometimes part of an interim management plan to support glycemic control, and the evidence on stevia in particular makes it a more reasonable choice. For people with cardiovascular risk factors, the erythritol and NutriNet-Santé findings are reason to look at what's actually in the protein bars, electrolyte powders, and "no sugar added" products that often stack up across a day. For people with gut symptoms, irritable bowel patterns, or unexplained bloating, polyols like sorbitol, xylitol, and erythritol commonly drive symptoms that get attributed to other foods.
How to apply this now
A few practical pieces if you're trying to make sense of the sweetener picture. Read the ingredient panel, not the front of the package. Words like "sugar-free," "zero sugar," "diet," and "keto-friendly" almost always indicate the presence of one or more sweeteners. The names to know are aspartame, sucralose, acesulfame potassium, saccharin (the older artificial sweeteners), and erythritol, xylitol, sorbitol, and maltitol (the polyols). Steviol glycosides (from stevia) and monk fruit extract have the most favorable evidence at this stage. Honey, agave, and maple syrup are not metabolically meaningfully different from sugar, despite their natural-foods reputation.
The bigger move is to reduce the daily sweetness load overall. Drink water. Brew unsweetened tea or coffee. Eat whole fruit instead of fruit juice or fruit-flavored products. Cook from whole ingredients when you can. Let your taste recalibrate over a few weeks and watch what happens to your cravings. None of this requires perfection. It requires direction.
If you have diabetes, cardiovascular disease, irritable bowel symptoms, or any condition where sweetener choice might matter clinically, please work with a clinician who can review your full picture. The science here is still evolving, and a thoughtful conversation with someone who knows the current literature will land better than a label-reading rule.
Frequently asked questions
Should I throw out everything with artificial sweeteners?
No need to panic-clean the pantry. The research points toward lowering your overall sweetness load over time, not swapping one product for another in a hurry. If you have diabetes, cardiovascular risk, or gut symptoms, that's where a closer look at sweetener use makes the most sense.
Which sweeteners have the most reassuring evidence?
Stevia (from steviol glycosides) and monk fruit extract have the most favorable metabolic profiles of the options studied so far. The data on them are reassuring at this stage, though still short on long-term outcomes. Reassuring isn't the same as proven.
Are "natural" sweeteners like honey or agave any better?
Not really. Honey, agave, and maple syrup aren't metabolically different from sugar in any meaningful way, despite their natural-foods reputation. They still add to the daily sweetness load the same way table sugar does.
Could sweeteners be behind my bloating or IBS symptoms?
They can be. Polyols like sorbitol, xylitol, and erythritol are common triggers for bloating and irritable bowel patterns, and the symptoms often get blamed on other foods. A trial period without them, ideally with some guidance, can clarify whether they're part of your picture.
What does whole-person care suggest instead?
The bigger move is reducing the daily sweetness signal so your taste can recalibrate, which tends to happen within a few weeks. Drink water, brew unsweetened tea or coffee, eat whole fruit, and cook from whole ingredients when you can. None of it requires perfection, just direction.
References
Suez J, Cohen Y, Valdés-Mas R, et al. Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance. Cell. 2022;185(18):3307-3328.e19. PMID: 35987213. DOI.
Debras C, Chazelas E, Sellem L, et al. Artificial sweeteners and risk of cardiovascular diseases: results from the prospective NutriNet-Santé cohort. BMJ. 2022;378:e071204. PMID: 36638072. DOI.
Witkowski M, Nemet I, Alamri H, et al. The artificial sweetener erythritol and cardiovascular event risk. Nat Med. 2023;29(3):710-718. PMID: 36849732. DOI.
van den Heuvel M. The Sweetener Trap: Are Sugar Alternatives Backfiring? Medscape News Europe. May 22, 2026. Original AANP digest link: https://www.medscape.com/viewarticle/sweetener-trap-are-sugar-alternatives-backfiring-2026a1000gm6
A note before you go
This is for educational purposes and is not a substitute for individualized medical care. If you have diabetes, cardiovascular disease, or any condition where your sweetener choices might matter clinically, please work with a clinician who can review your full picture and help you decide what fits your situation.
Related reading
Reviewed by Joyce Knieff, ND, LAc on 2026-06-09.
If this resonates with what you're experiencing and you'd like to explore a naturopathic approach, book a consultation with our clinic.
Comments