Researchers warn physicians about potential dangers of sucralose

By Lisa Marie Basile | Fact-checked by Davi Sherman
Published June 12, 2023

Key Takeaways

  • Sucralose was approved by the US Food and Drug Administration in 1998 after several claims were made about its safety. However, recent research shows that sucralose may be associated with health concerns—contrary to past claims.

  • New research shows that recent commercial sucralose samples contained up to 0.67% sucralose-6-acetate (S6A), a genotoxic compound. 

  • While sucralose isn’t the same as S6A, experts suggest that MDs talk to their patients about the potential risks associated with ingesting sucralose.

Chances are, you or your patients have indulged in certain soft drinks containing sucralose (also called Splenda), a nonnutritive artificial sweetener. With its zero calories and super-sweet flavor—it’s 600 times as sweet as sucrose, a natural sugar—it’s often billed as a healthy alternative to raw sugar. It’s even added to baked goods and pharmaceutical products.[][]

Recent research, however, indicates that sucralose may not be a healthy option. A May 2023 article published in Journal of Toxicology and Environmental Health: Critical Reviews explored the toxicological and pharmacokinetic properties of sucralose-6-acetate (S6A), “an intermediate and impurity in the manufacture of sucralose.” Researchers found some alarming information.[]

The study's lead author, Susan S. Schiffman of the Joint Department of Biomedical Engineering, University of North Carolina/North Carolina State University in Raleigh, NC, told MDLinx that the most surprising finding was that “[This] metabolite and contaminant of sucralose called sucralose-6-acetate was genotoxic.…[It] caused breaks in DNA, which carries our genetic information.”

It’s important to note that sucralose, which was approved by the US Food and Drug Administration (FDA) in 1998, is not automatically the same as S6A. However, the researchers found that “recent commercial sucralose samples were found to contain up to 0.67% sucralose-6-acetate.” The researchers also noted studies showing that a “rodent model found that sucralose-6-acetate is also present in fecal samples with levels up to 10% relative to sucralose, which suggest that sucralose is also acetylated in the intestines.”[][]

The researchers pointed out that historical studies made several claims about sucralose prior to its regulatory approval:[]

  • Sucralose is stable in vivo, passing through the intestine unchanged.

  • Sucralose does not affect gut health.

  • Sucralose does not affect intestinal tissue.

  • Sucralose does not bioaccumulate.

  • Sucralose does not affect metabolism, including blood glucose or insulin. 

  • Sucralose is not genotoxic, with “no associated biologically significant consequences, and is heat stable.”

However, the article in the Journal of Toxicology and Environmental Health: Critical Reviews shows evidence to the contrary on all counts. The researchers write, “Many scientific research investigations since regulatory approval…do not corroborate any of the six early historical claims regarding the biological fate or safety of sucralose.”[]

  • Regarding the stability of sucralose in vivo, the researchers write that “Two acetylated sucralose biotransformation products were found in urine and feces of rats dosed with sucralose,” with the more abundant being S6A. This goes against the original claim that sucralose remains stable and unchanged in the body. 

  • Regarding the effect of sucralose on the gut microbiome, the article notes that sucralose does, in fact, disrupt the microbiome in the GI tract in humans and animals. Moreover, pregnant people ingesting sucralose disrupt the microbiome of the fetus; sucralose has also been found in human breast milk.

  • Sucralose does change intestinal tissue, contrary to original claims. Researchers include a list of related findings: Sucralose ingestion induced histopathological changes, including epithelial scarring; increased bacterial infiltration into the ileal lamina propia in Crohn's disease; elevated certain cytotoxic cells; and promoted inflammation and colitis-associated colorectal cancer risk. They also note that in vitro studies, sucralose “enhanced biofilm formation along with bacterial invasion into gut epithelial cells.” Ingesting sucralose also affected offspring. 

  • Regarding bioaccumulation, sucralose was “found to bioaccumulate in adipose tissue of rats and was present two weeks after cessation of a 40-day feeding period even though it had disappeared from the urine and feces.”. 

  • After consuming glucose, The researchers note that if ingested via liquid or capsules and taken with a carb or other zero-calorie sweetener, some humans might experience altered glucose and insulin levels in the plasma. Researchers also found that sucralose could affect other hormone levels, including glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, stimulating insulin production. If ingested by a pregnant person, sucralose can alter the offspring’s metabolism, “including downregulation of hepatic detoxification mechanisms and changes in bacterial metabolites.” Additionally,  sucralose could “blunt thyroid function.” 

  • Lastly, the researchers stated that independent research has shown that sucralose damages DNA, enhances antimicrobial resistance, and increases cancer risk.  Additionally, when heated, sucralose could generate toxic compounds called chloropropanols. When ingested prenatally in mice, it induced leukemia in male offspring. At the same time, another model showed “significant elevation in the number and size of colorectal tumors” after ingestion of sucralose. 

In response to this research, the Splenda® Brand, owned by Heartland Food Products Group, released a statement stating, “As for this study, no conclusions can or should be drawn about Splenda® Brand Sweeteners from this study for the simple reason that it did not analyze any Splenda® Brand products or ingredients…We can confirm that S6A is not present in Splenda Brand sucralose down to the lowest detection limit possible, which is a .001% sensitivity level. The sucralose in Splenda Brand sweetener is made 100% in the USA.”

How should you talk to their patients about sucralose?

According to Schiffman, MDs should talk with their patients about sucralose intake. “It would be helpful for MDs to ask patients if they consume sucralose products. This is important because sucralose consumption can cause leaky gut and reduce beneficial bacteria in the gut, along with other negative health effects,” she says. 

Kelsey Costa, MS, RDN, agrees. “Doctors need to support patients in making informed decisions regarding their dietary and lifestyle choices. They can do this by offering information about natural alternatives, such as honey, dates, stevia, and monk fruit,” she says. 

More so, Costa suggests that MDs teach patients to read food labels carefully. “Finally, doctors may advise their patients to seek evidence-based nutrition advice from accredited professionals, such as registered dietitians,” she adds. 

“Until further research is presented,” Costa says, “doctors may [want to] advise their patients to avoid or limit their consumption of sucralose and other artificial sweeteners.” According to the study’s findings,” Costa continues, “even one daily drink sweetened with sucralose could surpass the genotoxicity threshold, indicating potential hazards.”

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