So what’s the difference between a probiotic and a prebiotic?

The term “probiotic” has been with us for a while, and unlike many other health substances, the general perception of what the term means is more or less accurate.

It’s a bacteria that does good things for your body.

However, a newer term has started to creep up that has very similar semantics: pre-biotics.

You’ll often see it on the ingredient list of supplements. For example, the supplement cyto-greens advertises inulin as a prebiotic on its label:

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Athletic Greens does something similar, and I’m sure there are others.

So what exactly is a prebiotic?

A prebiotic is a non-digestible substance that sticks around in your colon and enhances the ability of probiotic bacteria in your body to reproduce.

There are a few important points to consider here.

1.  A prebiotic is not a sort of bacteria
2. A prebiotic is a form of fiber. Fiber is stuff that your body doesn’t digest and just sits around in your colon. Prebiotics are just a special type of fiber that promotes bacterial formation.
3. Prebiotics are typically long-chain carbohydrates. Practically all plant foods have some prebiotic substance to them.
4. Foods all by themselves are not prebiotic. Calling a food a prebiotic would be similar to calling a food a vitamin.

Health Benefits of Prebiotics and Probiotics

The health benefits of probiotics are pretty widespread. Bacteria do a lot of good things in your body including:

• removing harmful toxins in the body
• help your body metabolize fat and sugar more efficiently
• help your body remove cancerous cells from the body
• take up space in your colon that would otherwise be occupied by bad bacteria
• suppress hunger

And the list goes on. And it’s an impressive list indeed. Bacteria are involved in almost all of the body’s cellular functions, and a healthy balance of microbiota  is very important to your health.

The health benefits of prebiotics are more or less as follows:

• the typical benefits of fiber (because it is fiber)
• helps your body make more probiotics

Which One Is Better?

While they both help, probiotics are more essential to health. Their benefits are harder to replace. Since prebiotics are a form of soluble fiber, those health benefits can be replicated by a wide variety of foods. And the only other useful thing prebiotics do is help your body make more probiotics (especially bifido bacteria). If that’s the case, I’d rather just have the real thing.

Supplements

The issue of probiotics and prebiotics is particularly germaine to buyers of supplements, since you’ll see both advertised on labels.

As one who makes supplements, I can tell you that probiotics are more expensive to source, and more difficult to incorporate into mixtures.

Prebiotics are fairly cheap and easy to source. Fiber is abundant in the plant kingdom. That doesn’t mean prebiotics are bad (they’re not), and a reasonable amount are helpful, especially when combined with probiotics.

However, I don’t consider the inclusion of prebiotics in mixtures to be necessary at all. They’re easily found elsewhere (especially if you follow a plant-based diet).

So, I’d look at the issue like this:

• Lots of probiotics and reasonable portion of prebiotics: best
• Lots of probiotics: very good
• Lots of prebiotics and no probiotics: “meh” – This is merely a way of disguising filler ingredients.

I’ll add that the bulk amounts of pro and prebiotics your body needs are not the same, so comparing the pure volume of each isn’t a good idea. The relevant metric for measuring probiotics is the number of species in the mixture.  This is usually expressed in billion parts/gram, and even formulas with copious amounts of probiotics might only have 75-200 mg per serving.

Prebiotics are best measured with traditional units like mg or g. I’d say up to 600 mg is fine.

References

Gibson, Glenn, et. al. “Dietary Modulation of the Human Colonie Microbiota: Introducing the Concept of Prebiotics” Journal of Nutrition. August 1994. Pgs. 1401-1413.

URL: http://ilri.org/biometrics/Publication/Abstract/Case%20study%2017%20-1.pdf

Schrezenmeir, Jürgen et. al. “Probiotics, prebiotics, and synbiotics—approaching a definition” American Journal of Clinical Nutrition.  May, 1999. Pgs. 10525-10575.

URL: http://www.ajcn.org/content/69/5/1052S.long