Intake of too little dietary fiber and too much added sugar is a major contributor to obesity, type 2 diabetes, and heart disease. One major source of added sugar is traditional soda, which has long been linked to obesity, cardiovascular disease, kidney problems, fatty liver disease, tooth decay, and other health complications.
Now, a small preprint study suggests that one commercially available prebiotic soda may produce lower short-term post-meal glucose spikes than Coca-Cola in adults with overweight or obesity.
Prebiotic soda is a popular beverage containing dietary fibers that our body can’t digest, feeding the microbes in our gut. These drinks are often claimed to help with constipation, bloating, irritable bowel syndrome, and inflammatory bowel disease. Prebiotics occur naturally in fruits, vegetables, and whole grains such as bananas, leeks, onions, garlic, asparagus, artichokes, wheat, and barley.
Traditional sodas, meanwhile, are sugar-sweetened beverages associated with obesity, heart disease, kidney disease, non-alcoholic fatty liver disease, cavities, and other health complications.
Compared to traditional sodas, prebiotic sodas generally contain less sugar and fewer calories while including plant-based prebiotic dietary fibers.
In the new study, a research team led by Colleen F. McKenna and Chad Cook of Biofortis compared a commercially available prebiotic soda containing 3 g of total sugars and 6 g of dietary fiber with a traditional soda containing 39 g of total sugars and no dietary fiber, with or without a meal, to examine after-meal, glucose responses in generally healthy adults.
However, the findings should be interpreted cautiously. The study involved only 30 participants, measured responses over just a few hours, and has not yet undergone peer review. It was also an open-label trial, meaning participants knew which beverage they were consuming, and the study was funded by OLIPOP, the manufacturer of the prebiotic soda tested.
The study included 30 men and women aged 18-65 years with obesity or overweight, but who were otherwise healthy. Participants were selected because their weight status puts them at an increased risk of heart disease. Researchers screened participants based on fasting glucose levels below 126 mg/dL, controlled blood pressure below 140/90 mm Hg, and non-use of tobacco/nicotine or marijuana products. Individuals with a diagnosed history of diabetes, eating disorders, gastrointestinal disorders, or other clinically relevant conditions were excluded.
Pregnant women and lactating mothers were also excluded. In an at-home setting participants consumed either a prebiotic soda or a traditional soda with or without a carbohydrate-rich meal as a daily lunch in a randomized controlled crossover design for four consecutive test days.
Each test day, participants were asked to consume breakfast no later than 8am. From 8am to the time of the experimental lunch, participants were instructed to refrain from consuming any food or beverages, with the exception of water.
The experimental lunch included a 12-fluid-ounce (355-ml) carbonated beverage – either a modern prebiotic soda or traditional soda – with or without a plain bagel and cream cheese. Participants were asked to complete the lunch within 15 minutes. The following three hours served as a post-meal observational period, during which participants were asked to refrain from any food or beverage, again, with the exception of water.
Participants were instructed to maintain their usual diets and physical activity patterns throughout the study, while avoiding alcohol, vitamin C supplements, and fiber or prebiotic supplements. Vigorous physical activity was prohibited for the 24 hours leading up to screening and the mornings of test days throughout the study period.
Researchers recorded that after-lunch (postprandial) glucose levels were lower with the prebiotic soda, with or without a carbohydrate-rich meal. Glucose rise was also lower with the prebiotic soda than with the traditional soda. The team also reported that the prebiotic soda did not significantly affect post-meal glucose dips, second-meal timing or energy intake, perceived hunger, or alertness.
The findings are notable because they measured the impact of a lower-sugar prebiotic soda on postprandial blood glucose compared to a traditional sugar-sweetened soda in adults with overweight or obesity.
The prebiotic soda resulted in significantly lower post-meal glucose excursions compared to the traditional soda when consumed either alone or with a meal.
Importantly, the researchers say the lower sugar and carbohydrate content of the prebiotic soda was likely the primary reason for the reduced glucose response. The study was not designed to determine whether prebiotic fiber itself improved blood sugar regulation or gut health.
The prebiotic soda tested in this study contained 28 (72%) fewer grams of total carbohydrate and 36 (77%) fewer grams of total sugars than the traditional soda. The researchers wrote, “This lower carbohydrate load is likely the primary contributing factor to lower glucose flux with [the prebiotic soda].”
They added, “Overall, acute prebiotic soda consumption with and without a meal reduces postprandial glucose excursion, without affecting second meal behavior or perceived hunger and alertness, compared to traditional soda.”
The researchers suggest prebiotic sodas may serve as lower-sugar alternatives to traditional soft drinks. However, the study did not directly test gut microbiome changes or long-term health outcomes.
The study has not yet been peer reviewed and was published as a preprint on medRxiv. Because it was a small, short-term, sponsor-funded study comparing a single prebiotic soda product against Coca-Cola, the findings should not be interpreted as proof that prebiotic sodas generally improve blood sugar control or gut health.
Source: medRxiv
Fact-checked by Darren Quick
