Sucralose: This Zero Calorie Sweetener’s Alarming Effects on the Gut Microbiome

single silver spoon of sugar or artificial sweetener with black background

This is a guest blog post by Lucas Irwin, NASM-PES, MBA, author and CEO of Steelhouse Fitness and Rebel Mindfulness.

Sucralose is an artificial sweetener made from the combination of chlorine and sugar molecules and is commonly sold under the brand name Splenda.

Although this sweet, calorie free sugar substitute is tempting, it may be doing more harm than good.

If you rely on sucralose as a sweetener you need to read this article!

Sucralose is Everywhere

Whether it’s a protein powder or “sugar free” drink , sucralose can easily sneak up on you.

According to the manufacturer of sucralose, Tate & Lyle, sucralose is an ingredient in over 4,000 products food and beverage products.

Although the FDA claims sucralose is safe, it is a novel compound that has never before been eaten by humans.

We know that other artificial sweeteners like aspartame have been reported to cause negative health effects, so what does the science say about sucralose?

Sucralose Sinks the Microbiome

According to a study published in the Journal of Toxicology and Environmental Health, sucralose negatively impacts the gut microbiome.

Amongst other things, the microbiome helps us to absorb antioxidants, vitamins and minerals, supports our immune system, helps keep us “regular”, and may even influence whether or not we become obese.

Obviously the microbiome is very important, so why is sucralose so bad for the gut?

The reason is that most of the sucralose you eat isn’t broken down during digestion and the molecule arrives at the large intestine (the home base of your gut microbiome) fully intact.

Once gut bacteria come across it, they chow down and die off.

In experiments with animal models, sucralose was found to kill off as much as 50% of the “good” gut microbiome.

What About Other Artificial Sweeteners?

Similar findings were discovered with another artificial sweetener called saccharin, and it is suspected that a similar mode of action is at work as well.

Researchers have found that although our bodies can’t metabolize artificial sweeteners, our gut bacteria can, and that’s why they can still cause us problems.

With this new information, it’s important to consider not only how a sweetener tastes, but how it digests and impacts our inner ecology as well.

Natural Alternatives

Stevia rebaudiana is a relative of the sunflower, and is known colloquially as “candy leaf”, “sweetleaf”, and “sugarlear”. Stevia contains natural compounds that 250-300 times sweeter than sugar, but it contains no calories and may even have positive health effects.

Monk fruit, or luo han guo is another natural sweetener with many years of safe, traditional use.

Not all natural sweeteners are sweet however. The naturally occurring sugar alcohol erythritol is common in many supplements and protein powders but it can cause gas, bloating, and digestive upset.


When picking a calorie free sweetener, it pays to do your homework.

There are natural alternatives that will still save you calories while causing far less harm to your vital gut microbiome.

Editor’s Note: This article was originally posted June 2014 and has been completely revamped and updated for accuracy and comprehensiveness.

Also published on Medium.