Trendy ‘gut-healthy’ sodas may lead to digestive issues and cancer, experts warn. 

Touted by Paris Hilton, Jennifer Lopez, Kim Kardashian and Billie Eilish, prebiotic sodas like Poppi and Olipop have gained a widespread following over claims they are healthy alternatives to traditional sodas that can reduce harmful inflammation and boost good gut bacteria. 

Costing about $2.60 per can, the drinks contain around 50 calories each and use natural sugar substitutes like Stevia or agave.

They also contain inulin, a type of prebiotic fiber that helps ‘feed’ healthy bacteria in the gut microbiome – the collection of good bacteria in the gut – by producing short-chain fatty acids. 

Increased amounts of fatty acids have been shown to improve digestion by regulating bowel movements and preventing constipation.

However, emerging research suggests short-chain fatty acids linked to inulin may increase the risk of certain cancers in the liver or colon by increasing inflammation and promoting tumor growth.  

Doctors are now warning against consuming inulin on a regular basis, though they have also cautioned more research is needed. 

The warning comes several months after prebiotic soda brand Poppi was hit with a $5million lawsuit over claims the company ‘misled’ consumers and that the fiber content was too low to provide any benefits. 

Olipop is one of the most popular prebiotic soda brands, generating $500million in sales last year

Paris Hilton is among Poppi’s high profile fans. As a paid partner, she participated in an LA launch event last year

Andrew Gewirtz, a biomedical science professor at Georgia State University, told Axios: ‘The occasional can is unlikely to cause major harm.

‘It’s regular consumption that I’m not convinced is safe.’ 

Inulin is a form of dietary fiber found naturally in some plants chicory root, garlic, onions, and Jerusalem artichoke. It is also considered a fructan, a type of prebiotic, meaning it can help feed ‘good’ bacteria in the gut.

Gut bacteria convert inulin and other prebiotics into short-chain fatty acids, which can help strengthen the gut’s protective lining and reduce inflammation. 

Poppi and Olipop are two of the most popular prebiotic soda brands, generating about $500million each in sales last year. 

One can of Poppi contains three grams of dietary fiber, while Olipop can have up to nine grams, depending on the flavor. 

While inulin has been touted for its digestive benefits, Gewirtz claims: ‘Consuming grams of inulin regularly in supplements, beverages and inulin enriched foods may increase risk of cancer, potentially by dampening anti-tumor immunity.’

Gewirtz and a team from the University of Toledo published a study in 2018 looking at the effects of ‘highly refined’ fibers like inulin on mice. 

Several of the mice who had inulin added to their diets developed jaundice, a sign of liver failure. After six months, they developed liver cancer. 

A 2024 case study authored by the same team suggested inulin ‘may be carcinogenic.’ 

The man in the case study had his first colonoscopy to screen for colon cancer at age 56, which came back normal. 

But seven years later, another routine cancer screening showed a malignant tumor at the start of his large intestine. The disease had also spread to his lymph nodes.  

Now in his 60s, the man had no known colon cancer risk factors like obesity, alcohol use, or family history, and his diet was rich in organic, home-grown vegetables.

His only lifestyle change in the time between screenings was adding four grams of inulin powder daily to his diet. 

Researchers have suggested prebiotic sodas with inulin may raise the risk of certain cancers like colon cancer (stock image)

Researcher Dr Matam Vijay-Kumar of the University of Toledo said the patient contacted him after reading his previous research on inulin.

Dr Vijar-Kumar said last year: ‘My first thought was how can he pinpoint that inulin caused colon cancer? It’s incredibly difficult to identify a single cause of disease, particularly with cancer.

‘However, after extensive communication with him about his medical history and lifestyle, combined with what we know from studies in mice, we were convinced that there was a plausible link.’ 

Gewirtz suggested short-chain fatty acids may be responsible for this increased risk by triggering inflammation and increased cell production and division. This increases the risk of cancer cell production and tumors forming. 

However, he noted: ‘Further studies are needed to help identify who might benefit from [inulin] and who should avoid it.’ 

To boost healthy gut bacteria, he instead suggested increasing fiber intake through foods like artichokes, broccoli, lentils, seeds, oatmeal, brown rice, avocado, and raspberries. 

Olipop and Poppi did not immediately respond to DailyMail.com’s request for comment.