- Sucralose (Splenda) is an artificial sweetener that’s been sold in the US since the nineties. The FDA categorized sucralose as safe, but since then, new research has called sucralose’s safety into question.
- Recent rat studies suggest that sucralose may disrupt your gut bacteria.
- Sucralose metabolites may build up in your fat cells, too, and researchers don’t know what those metabolites do.
- Cooking with sucralose creates possible carcinogens called chloropropanols that you’re better off avoiding.
- There haven’t been many studies on sucralose in humans, so it’s hard to say one way or another whether sucralose is okay to eat. There are much better-studied sweeteners that you can use instead of sucralose. Read on to find out which sweeteners are best.
Sucralose (you might know it as Splenda) is an artificial sweetener that’s been sold in the US since the nineties. Sucralose has been at the center of the artificial sweetener debate, with arguments from both sides. Some people claim it’s totally safe; other say it causes everything from cancer to DNA damage.
The truth is somewhere in the middle. A growing body of evidence suggests sucralose may not be good for you…but most of the research is in rats, so it’s hard to say anything definitively. What’s more certain is that sucralose is not “biologically inert,” as its original FDA safety application claims. So is sucralose safe?
Prefer to listen to this article? Click the play button below for the audio version.
The TL;DR for this article is that it may not be, and that there are much better sweeteners out there. Let’s take an honest look at the research about sucralose, and talk about what sweeteners are actually good for you.
Download the free Bulletproof Roadmap for a list of healthy and not-so-healthy sweeteners
Does sucralose (Splenda) cause cancer?
Sucralose made international headlines awhile back, when an Italian study found that it causes leukemia (blood cancer) in rats.[ref url=”https://www.tandfonline.com/doi/full/10.1080/10773525.2015.1106075″] Let’s take a closer look at that study.
Researchers gave rats a variety of doses of sucralose throughout their lifespan, starting in the womb and continuing until death. Male rats who got higher doses of sucralose developed significantly more cancer in their lifetimes.
Sounds pretty damning for sucralose… until you look at the doses the researchers used. The rats that got cancer were consuming the human equivalent of 70-2,000 diet sodas per day, from the womb until death. Unless you’re drinking pure liquid sucralose, the results don’t really apply.
A follow-up review looked at sucralose’s safety in humans and found it to be safe. The researchers did a good job on the review…but it was funded by the company that sells Splenda, which means you should take the results with a grain of salt.[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5152540/”]
So does sucralose, at a realistic dose, cause cancer in humans? Probably not. That said, there have been more reasonable studies on sucralose that are concerning.
Sucralose may wreck your gut bacteria
Other research on sucralose suggests that it may damage good gut bacteria. Rats fed sucralose at levels that mimic actual human consumption saw a nearly 50% decrease in beneficial gut bacteria, their intestinal pH (a measure of acidity) rose, and they developed heightened enzyme levels, which could interfere with absorbing other nutrients and drugs.[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/18800291″]
This study is still in rats, but it suggests that sucralose may mess with your gut bacteria. You’re probably better off avoiding it.
Sucralose metabolites may build up in your fat cells
Chemists make sucralose by attaching chlorine molecules to normal refined white sugar. The chlorine molecules make the sugar much harder for humans to digest; the theory is that you don’t metabolize the sweetener and it passes through your body undigested. Recent research in rats has called that claim into question.
Rats fed small doses of sucralose did in fact metabolize it, and two of the metabolites built up in the rats’ fat cells.[ref url=”https://www.tandfonline.com/doi/full/10.1080/15287394.2018.1502560″] Researchers don’t know what those metabolites do. Again, this study is not in humans, but you probably don’t want to risk untested compounds building up in your fat cells, especially since that’s usually your body’s way of protecting you from stubborn toxins it has trouble excreting.
Heating sucralose creates carcinogens
The chlorine molecules in sucralose make it quite stable at room temperature, but when you heat sucralose up — say, by cooking with it — it forms chloropropanols, which are possible carcinogens.[ref url=”https://www.ncbi.nlm.nih.gov/books/NBK373196/”][ref url=”https://www.sciencedirect.com/science/article/pii/S0308814609005378″]
A lot of products that contain sucralose are heated at some point, which means they could contain potential carcinogens. Again, it doesn’t seem like it’s worth the risk.
Is sucralose safe for humans?
The big question is whether sucralose is safe for humans, and the answer is not as definitive as you might hope. There just haven’t been that many human studies on sucralose. Most of them are in rodents, and the rodent studies bring up some troubling questions about sucralose’s safety.
At best, sucralose is an unknown. In the next 20 years, human research may find that it’s totally safe, or it may find that sucralose damages gut bacteria, causes metabolites to bioaccumulate in your fat cells, and creates carcinogens.
Why take the risk? With its chemical aftertaste, sucralose is a poor substitute for sugar anyway. You’re better off choosing a natural, well-tested alternative sweetener. Below are a few options.
What’s the best alternative sweetener?
Xylitol is a natural component of birch syrup that’s closely related to sugar. It tastes almost identical to sugar, but its molecules are arranged in such a way that humans don’t have the enzymes to break it down, so it won’t affect your blood sugar. Xylitol is well-tested and well-tolerated. It also inhibits pathogenic bacteria in your mouth, which makes it good for your teeth (a lot of toothpaste companies use xylitol).[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4232036/”] Note that your gut bacteria ferment xylitol and produce small amounts of gas. That’s fine at low doses, but at higher doses, xylitol can cause digestive distress. Keep it under about 15 grams a day.
Erythritol is a cousin of xylitol that’s also an excellent sweetener. While it doesn’t have the same dental benefits, your gut bacteria aren’t as good at fermenting it, so it’s less likely to give you stomach troubles.
Monk fruit extract (luo han guo) is a strong antioxidant that’s several times sweeter than sugar. It won’t spike your blood sugar at all and it doesn’t have any strange aftertaste.
Stevia is another great natural sweetener. You may find it has a weird taste, depending on your genetics. If stevia tastes strange to you, opt for monk fruit, or try mixing stevia with one of the other sweeteners on this list.
You have a lot of options that both taste better and are less questionable than sucralose. Thanks for reading.
