Study warns prebiotic sodas’ “health halo” may mask limited fiber and gut benefits

A study, presented at the ongoing Nutrition 2026 (July 25–28) flagship annual meeting of the American Society for Nutrition, revealed that prebiotic sodas may contain more sugar and less fiber than marketed on the product label. 

Prebiotic sodas have seen an increase in popularity in recent years, tapping into product innovations for gut health while being low in calories. The researchers highlight that prebiotic sodas are among the fastest-growing beverage segments in the US. 

However, their study revealed that prebiotic sodas contained 35 calories, 5 g of fiber, and 5 g of sugar on average per 12-ounce (355 mL) can. With this sugar and calorie content, they scored lower than fruit drinks and regular sodas but higher than flavored sparkling water and diet soda. 

Nutrition Insight sits down with co-author of the study, Carlos Soto Díaz, MPH, a Ph.D. candidate at the University of North Carolina at Chapel Hill, US. 

“The largest difference involved a brand that contained 10 g of total sugar while displaying a ‘no added sugar’ claim. The claim is legally permissible because the sugar came from ingredients such as fruit juice rather than added sweeteners. Similar claims are commonly used on 100% fruit juice products, which contain substantial amounts of naturally occurring sugar but no added sugar.”

“However, consumers may interpret ‘no added sugar’ as meaning the product is sugar-free or very low in sugar, potentially leading them to consume more sugar than intended.”

He says many products include nutrition and functional claims that may overstate their nutritional quality. This raises concerns that such claims may create a “health halo,” leading consumers to believe the product is healthier than its overall nutritional profile suggests.

Analyzing over 100 sodas

The researchers analyzed 108 prebiotic sodas launched in the US between 2021 and 2025, all of which used the term prebiotic in the name, on the packaging, or on the ingredient list. 

Soto Díaz says the marketing with claims such as “no added sugar” may lead consumers to assume the products contain little or no sugar without checking the nutrition facts label. According to the study, the sodas contained more fiber compared to regular sodas and other beverages, spanning two to nine grams per can. However, the researchers note that the term prebiotic can be used without specifications of fiber amount, urging caution that the actual fiber content in these cans cannot be a reliable fiber source just because they are labeled as “prebiotic.”

Soto Díaz says the marketing with claims such as “no added sugar” may lead consumers to assume the products contain little or no sugar without checking the nutrition facts label. 

“As a result, consumers could unintentionally consume more sugar than expected, which, over time, may contribute to excess calorie intake.”

Uncertain gut health benefits

In terms of health benefits from prebiotic sodas in comparison with regular sodas, Soto Díaz explains that they usually contain fewer calories and less sugar, and they may therefore be a better alternative for consumers replacing regular soda. On the contrary, he warns that they may be a less healthy alternative overall for those consuming beverages with low sugar and calorie content.

Meanwhile, the potential gut health benefits of prebiotic sodas are uncertain. 

“There is currently no research specifically examining the effects of prebiotic sodas on gut health, and some prebiotic fibers may require higher doses to produce meaningful effects,” notes Soto Díaz. “Because the median amount of prebiotic fiber in these products was relatively low, consumers should not assume that drinking them will provide a meaningful gut health benefit.”

He explains that while certain types of prebiotic fibers have been shown to support gut health, the extent to which the amounts found in these beverages provide meaningful benefits is still unclear.

Any potential benefits should be considered alongside the product’s overall nutritional profile, including calories, sugars, and non-nutritive sweeteners, he urges.

“The main takeaway is that consumers should read the Nutrition Facts label rather than relying solely on marketing claims such as ‘no added sugar’ or the use of a ‘prebiotic.’ They should check whether the product is truly low in total sugar and contains a meaningful amount of fiber,” concludes Soto Díaz.

“I would encourage consumers not to be swayed by marketing claims and to carefully review the nutrition facts label.”