TikTokers are spreading a false claim that Costco chicken can cause cancer based on scientific misinformation

• TikTokers are spreading a false claim that Costco's $5 chicken can cause cancer.
• TikTokers take issue with a common food additive sometimes confused with a substance used in X-rays.

TikTokers are spreading a false claim that Costco's famous rotisserie chicken — an item so popular the company's chief financial advisor once said he was willing to lose tens of millions to keep it at its $5 price — can cause cancer, based on scientific misinformation.

"What's really inside your Costco chicken?" food coach Jen Smiley (@wakeupandreadthelabels) asked TikTokers in an April 4 video with over 100,000 views, adding later, "you have chicken that may make you gain weight and have a carcinogen."

"It ain't worth the $5 #cancer," Bethany Ugarte captioned a similar September 4 video showing screenshots of studies without citations.

Costco chicken fears stem from the confusing nomenclature of one common food additive

Smiley and other TikTokers claim carrageenan, a natural additive used to thicken and preserve food, found in Costco chicken will lead to cancer.

Carrageenan is a natural substance found in seaweed. Dairy and dairy substitutes, deli meats, nutritional supplements, beverages, and infant formulas can all contain carrageenan, according to a paper published in the Critical Reviews in Food Science and Nutrition journal.

When scientists induce a chemical change to carrageenan, they produce a new substance called poligeenan or degraded carrageenan. Poligeenan is used in medical imaging, including X-rays of the mouth and esophagus.

The body cannot convert carrageenan to poligeenan. The environment required to produce poligeenan — high temperatures and acidic environments — occurs in laboratory settings and cannot be replicated within a human stomach.

Laboratory animals given high amounts of poligeenan developed lesions and tumors in the stomach. Carrageenan has no cancer-causing properties, and the substance even inhibited the growth of cancer tumors in one rodent study.

Smiley claimed foods could contain both carrageenan and poligeenan. The US does not approve poligeenan as a food additive, and closely regulates carrageenan.

Some papers before 1988 did not differentiate between the two forms of carrageenan, which might have started the confusion. Studies can still fail to distinguish between the two, per CRFSN.

"Carrageenan is not carcinogenic, tumorigenic, genotoxic, or a tumor promoter or initiator, or a reproductive toxicant, and has no adverse effects on the immune system," researchers concluded.

Some are stepping up to stop the spread of misinformation

As misinformation spreads on the app, creators are stepping in to correct the conversation.

TikToker @FoodScienceBabe, a food scientist with a BS in chemical engineering who debunks food myths on social media, responded to Ugarte's video on September 9. The creator dispelled rumors that ingredients in the $5 chicken can cause cancer and criticized fearmongering as inflation impacts grocery bills.

"In a time when food is getting more and more expensive, this is really just not a time to be perpetuating this misinformation and creating unnecessary food fear," she said. (Food inflation is easing, but prices are still high by historical standards).

Other TikTokers, like @rantdelish, echoed similar sentiments, criticizing "the demonization of convenience" of time, cost, or its availability in wellness influencer culture.

Misinformation isn't new to social media, and while Gen Z is increasingly using TikTok videos to search for information over Google, a new NewsGuard study says 1 in 5 TikTok videos may contain misinformation.

In videos spreading food myths, misinformation is often combined with compelling viral ingredients: a sense of urgency, enticing visuals, and "science washing" — scientific-esque lingo and screenshots of studies that may be irrelevant or improperly characterized or cited. For the latter, viewers would need to pause and critically read through the screenshot to decide for themselves, an unlikely occurrence on an app famous for an endless supply of short, addicting videos.