Similar terms, different ingredients – and different effects on your digestive system.
If you wander down the supplements aisle at a grocery store, you’ll find a dizzying array of pills labeled prebiotics or probiotics. These supplements make plenty of vague promises to improve your health and aid digestion by strengthening your gut microbiome. But what does that mean?
First of all, what is your gut microbiome? What is a prebiotic, or a probiotic? Are they the same thing?
Perhaps the most important question of all, should we take them?
Microbes in Food, or Food in Microbes
Both prebiotics and probiotics are supplements. They aren’t intended to directly help our own human bodies but instead benefit our gut microbiome.
Inside your gut is a huge and varied population of bacteria. Collectively called a microbiome, that lives in our small and large intestine. There are more bacteria living inside each of us than there are human cells making up our entire body!. Each of us has a slightly different balance of bacteria, making each microbiome unique.
Our gut microbiome lives off of the food we eat, and they synthesize some of the vitamins we absorb. Hey, help our immune system stay in fit and fighting shape by helping our immune system learn the differences between friend and foe.
Prebiotics and probiotics are both related to this gut microbiome:
Probiotics are live cultures of bacteria. Probiotics can be natural, such as fermented foods like sauerkraut or yogurt. They can also be lab-grown, like pills found in the supplement aisle. A single probiotic may contain anywhere from one to 20 different strains of live bacteria.
Prebiotics are nutrients that are intended to feed bacteria. Many of the bacteria in our gut thrive off forms of starchy dietary fiber, which is concentrated in prebiotic supplements.
I like to compare our gut microbiome to the front lawn in front of the house. Taking probiotics is like spreading grass seed on the lawn, while prebiotics is like spreading fertilizer.
“What Should I Take?”
Probiotics get a lot more advertising than their prebiotic cousins. From yogurt promising to help regulate digestion, to specifically-formulated probiotic drinks, there are more live microbe options than there are “bacteria food” options.
Unfortunately, the answer to “which is the best probiotic to take?” tends to usually be “none of the above.”
There are several challenges to finding a great probiotic to take:
- We’re still learning how the microbiome works, and we don’t yet fully understand the interaction between the bacteria and our own digestive and immune health.
- Our microbiome is complex, with hundreds of different species of bacteria; most probiotics only contain a handful of strains and cannot match the complexity of our natural microbiome.
- Each of us has a different microbiome, so a probiotic that works for one person may not do anything for another.
- In order for a probiotic to make specific health claims, it must be reviewed by the FDA, which is an expensive and time-consuming process. This is why most probiotics make very vague, general claims to their health benefits.
In the end, adding foreign bacteria to our gut without changing the gut environment to match won’t do anything for our health. You can spread grass seed on a lawn, but it won’t help if the lawn is already overgrown with weeds.
What about prebiotics? Should we be taking a prebiotic?
Research into the benefits of prebiotics is still ongoing, but they may be a better approach. Instead of trying to select the exact right bacterial strains, prebiotics provide the nutrients that will encourage more beneficial bacteria to grow and thrive.
The best prebiotic is easy to spot – it’s dietary fiber!
Foods that are high in fiber – including artichokes, asparagus, spinach, leeks, bananas and oats – are all great choices. Another great choice is resistant starch, found in whole grains including rice, barley and sorghum, which has been shown to feed bacteria associated with better gut health.
We used to believe the only purpose for consuming dietary fiber was to “scrub out” our insides, like a pipe cleaner. Now, we understand that bacteria feed on that fiber, breaking down the tough fibres that we can’t digest ourselves. Many of the bacteria that thrive on fiber seem to be connected with a healthier gut, fewer digestive problems and fewer autoimmune disorders.
Our current Western diet contains far less dietary fiber than experts recommend. The average American only consumes about 15 grams of dietary fiber per day – which is about half of what experts recommend. So up that fiber intake – for your gut microbiome!
To recap: Prebiotics and probiotics are two supplements with similar sounding names that contain different ingredients. Both intended to benefit our gut microbiome, the diverse collection of different bacteria that we have inside our intestines. Probiotics contain live bacterial cultures, while prebiotics contain fiber and nutrients to feed the bacteria already there.
In the future, we may each take a probiotic, with a custom selection of bacteria tailed to our own individual microbiome. Most of the offerings these days, however, haven’t been shown to consistently provide reliable benefits. And can’t match the bacteria we already have in our digestive system.
Prebiotics, on the other hand, may be more useful because they’re broader, with food that many different bacteria can digest. The best prebiotic step we can take is adding more dietary fiber into our diets from raw or minimally processed foods.
Dietary fiber does a lot more than add bulk to food. It is a great food for our bacterial buddies inside our digestive system!