What Is Prebiotic Tea? FOS, Fiber and Caffeine Explained
Prebiotic tea is ordinary tea with prebiotic fiber added to it. The tea part behaves like tea. The prebiotic part is a soluble fiber that passes through the small intestine undigested and is fermented by bacteria in the large intestine. Waka's prebiotic black and green teas contain approximately 2 grams of beet-derived fructooligosaccharides (FOS) per 1 teaspoon serving, alongside approximately 30 mg of caffeine.
What a prebiotic actually is
The term has a specific technical meaning, and it is not the same as a probiotic. A probiotic is live bacteria. A prebiotic is a substrate that the microorganisms already living in your gut selectively use — in plain terms, a food source for existing gut bacteria rather than an addition of new ones.
Fructooligosaccharides are short chains of fructose units. They occur naturally in foods including chicory root, onions, garlic, bananas, asparagus and, as in Waka's case, sugar beets. Because the chains resist digestion by human enzymes, they reach the colon intact.
Where the fiber number sits in context
For a sense of scale, Mayo Clinic lists the National Academy of Medicine's daily fiber recommendations for adults at 21 to 38 grams, depending on age and sex. Two grams in a cup of tea is a small amount by comparison.
This is worth stating plainly because the category tends to imply otherwise. A prebiotic tea is simply tea with a little added fiber. It is not a fiber supplement, and it isn't a substitute for fiber from food.
Prebiotic tea vs. regular tea
| Regular instant tea | Prebiotic instant tea | |
|---|---|---|
| Serving | 1/4 tsp | 1 tsp |
| Caffeine | ~35 mg | ~30 mg |
| Added fiber | None | ~2 g FOS |
| Sweetened | No | No |
The serving size is larger because most of the spoonful is fiber rather than tea. See our fuller comparison, prebiotic tea vs. regular tea.
An honest caveat
FOS is fermented, and fermentation produces gas. Some people find fructooligosaccharides cause bloating or discomfort, and Mayo Clinic notes that adding a lot of fiber too quickly can lead to gas, bloating and cramping. If you're new to it, you can start with less than a full serving. If you have a digestive condition, check with your doctor first.
How to make it
Stir 1 teaspoon into 8–10 fl oz of hot or cold water. For iced, dissolve in about 2 fl oz of hot water first, then top with cold water and ice. Available in black and green in 5.3 oz pouches, unsweetened.
Frequently asked questions
Is prebiotic tea the same as probiotic tea?
No. Prebiotics are fiber that feeds bacteria already present. Probiotics are live bacteria. They are different ingredients doing different things.
Does it taste different from regular tea?
FOS is mildly sweet on its own, so prebiotic tea tastes slightly rounder than the unflavored versions even though it's unsweetened.
Can I make it hot or iced?
Yes. It dissolves fully in hot or cold water — see the directions above.
How much caffeine is in it?
Approximately 30 mg per 1 tsp serving for both the black and green versions, compared with about 96 mg in an 8 fl oz cup of brewed coffee, according to Mayo Clinic.
This article is for general information only and isn't medical or nutritional advice. If you have questions about caffeine, your diet or a health condition, talk to your doctor.
