Is Prebiotic Soda a Good Source of Fiber?

Is it possible to enjoy pop (or soda) without worrying about how unhealthy it is? That's the case being made by a flurry of prebiotic soda brands taking over the beverage aisles of grocery stores. They claim that their products contain less sugar and calories than traditional soda and are good for your gut health.  

So can these products really turn drinking a carbonated, flavored beverage from a vice into something virtuous?  

Prebiotics versus probiotics

If you’ve heard about prebiotics and probiotics but aren’t totally sure of the difference, here is a refresher:  

Probiotics are living microorganisms that are good for your gut microbiome, or the ecosystem of bacteria and other microbes in your intestine. You can consume them in fermented foods like yogurt, kimchi and kombucha.  

Prebiotics are substances that feed probiotics, promoting the growth and health of that “good" bacteria in your gut. Fiber is the most common form of prebiotic, but researchers have found other things can act as prebiotics too, like certain types of fatty acids as well as compounds called polyphenols, which are found in fruits and other plants.

It’s clear that you need both for a healthy gut microbiome, and incorporating fermented foods and foods high in fiber can support that. What’s less clear is how effective it is to get pro- and pre-biotics from other sources like supplements and beverages.  

“Not all probiotic sources are able to survive the stomach acid and make it all the way through the stomach and the upper intestine to get down to the lower intestine and repopulate the gut,” says Diane Javelli, RDCD, a clinical dietician at the Nutrition Clinic at UW Medical Center – Montlake.

Prebiotics aren’t living organisms and aren’t digested by your stomach, so they don’t have trouble getting to your gut — but they can have their own set of issues when extracted from whole foods.

Does consuming prebiotics in soda help the gut?

The most prevalent prebiotic fiber used in soda is inulin, which can be extracted from plants like agave, chicory and artichoke. Because it’s soluble, it works especially well for fiber formulations added to prebiotic beverages.  

“You add it to a drink and it dissolves,” says Christopher Damman, MD, a gastroenterologist at UW Medicine and an expert in the microbiome and its relationship to the body. “Unlike adding psyllium husk, which is what’s used in Metamucil — that would turn the liquid into a gel.”

Inulin also adds a slightly sweet flavor to the drinks without having to use sugar, another benefit for prebiotic soda companies. Different brands use anywhere from 2 grams to 9 grams in their drinks.  

But does consuming prebiotic fiber like inulin in soda actually help the gut?

“Prebiotics we know are helpful for supporting the health of the good bacteria in our gut microbiome,” says Javelli. “Whether or not these sodas do exactly the same thing or not, it's yet to be seen because there really hasn't been any research on it.”

Consuming a substance like inulin is a way to get dietary fiber. But getting just one kind of fiber, isolated from the whole food it came from, won’t necessarily give you the same benefits as the many kinds of fiber and other prebiotics and nutrients you ingest when eating whole grains, fruits and vegetables.  

“For somebody looking for a way to get more fiber in their diet, then it might be a way to get some extra fiber, but it shouldn't be their main focus,” says Javelli. "They should try to get it from whole foods first and a prebiotic soda is just kind of a nice extra.”

The risks of drinking prebiotic soda

Another reason not to overindulge or rely on prebiotic soda is that inulin does not agree with everyone’s gut.  

“Not all fiber is treated the same by different bodies and different microbiomes,” says Damman.  

Inulin can lead to gas and bloating in a lot of people and can make symptoms worse if you have irritable bowel syndrome. Javelli recommends anyone who has been told to watch their FODMAP intake be very careful with prebiotic sodas. Inulin can also draw water into the bowel, causing you to experience loose stools.

Other ingredients in these sodas can potentially cause issues, as well. For instance, some brands contain apple cider vinegar, which can cause acid reflux and heartburn for some people. Others contain herbs that can interfere with certain medications, including blood thinners. If you regularly take medication for a condition, make sure the ingredients in your beverage aren’t going to affect it.

Prebiotic soda versus regular soda

One thing that is safe to say? It’s better than normal soda.  

“If people can tolerate the fiber and they don't get gas from it, then it's probably a good way of transitioning out of drinking as much soda,” says Javelli. “If you just drink soda pop once in a while, it's probably not a big deal to replace it with anything, but for people who are regular soda drinkers, then there may be some advantage to switching to something that has less sugar.”

While normal soda can contain as much as 40 grams of sugar (80% of the recommended limit of 50 grams, or 12 teaspoons, of added sugar per day), most prebiotic sodas only contain 4 or 5 grams of the sweet stuff. They often also contain fewer artificial flavorings and other additives. 

How else can I get prebiotics in my diet?

If you enjoy prebiotic soda, you might be getting a bit of an extra fiber boost. But there are other, more proven ways to feed your gut microbiome:  

Tea

If you’re looking for another way to scratch the late morning itch for a beverage, consider black and green tea, which contain polyphenols that act as prebiotics.  

Spices

Studies have shown that culinary spices benefit 33 species of lactobacillus and bifidobacteria, two main kinds of probiotics in your gut.  

“Black pepper, cayenne, cinnamon, ginger, oregano, rosemary, turmeric — they found in studies that those kinds of spices actually increased the numbers of good bacteria streams that we have in our gut microbiome,” says Javelli.  

Oils

Another source of prebiotics is certain fatty acids found in oils. These include sunflower and olive oils; nuts and nut butters; and avocado.

Dairy

Dairy also has fatty acids, including Swiss and Colby cheese, homogenized milk, yogurt, butter and cottage cheese.

Fruit, vegetables and grains

Then there are the good old fruit, veggies and grains, which, as you likely already know, are the best source of dietary fiber. Some especially good ones are artichoke, asparagus, berries, beans, barley, eggplant, fruit, garlic, leeks, lentils, onions, peas, radishes, root vegetables, sweet (and regular) potatoes, tomatoes and yams.  

In short, prebiotic sodas are not a shortcut to a healthy gut, but they’re better than normal pop and come with a bit of a fiber boost.