It’s easy to confuse probiotics with prebiotics. They may seem to differ by just one letter, but the differences between probiotic foods and prebiotic foods go much further.
Probiotics or prebiotics? Their names cause constant confusion. The change of a single letter does not seem sufficient to differentiate two types of functional products that, on the other hand, have a lot in common.
However, their operation is what determines that their nature is so different, as we will now see. And it is not only their nature that differs. We can find other divergences between them that allow us, more or less, to classify some of their characteristics. These, of course, imply different applications and, therefore, different products to be found on the market.
Both of them coincide within the lively world of the so-called “functional foods”, although the functional property they have is not always clear. Functional foods are made to fulfill a specific function such as improving health and reducing the risk of contracting diseases. In the case of probiotics and prebiotics, their function is to improve the quality of our intestinal microbiota (the wrongly called “flora”), thus helping to prevent and improve health. So far their similarities.
Differences between probiotics and prebiotics food
In summary, we can say that probiotics are products with potentially beneficial bacteria added so that they can be incorporated into our digestive system. Prebiotics, on the other hand, are foods with dietary fiber, either added or natural, that help the microorganisms in probiotics, and those native to our system, to perform their functions.
Probiotics “are” alive and prebiotics are not
The biggest difference is that prebiotics contain microorganisms that are alive in their biological definition. That is, they move, feed, interact and reproduce. They can colonize our intestines and join the ranks of microorganisms that play in our favor.
Prebiotics do not. These are merely dietary fibres that are difficult to digest in the stomach. They help intestinal transit and, in addition, when they pass through the intestine they are used by the microbiota to feed itself. In fact, a probiotic can contain prebiotics (many do) to help these microorganisms settle in the intestine. In this case, by the way, it is still a probiotic to which a prebiotic has been added, and not the other way around, because it is the probiotic that is important.
Prebiotics always work, probiotics don’t
One of the biggest sources of debate regarding functional foods is whether they can be proven to work. This also applies to probiotics, but not prebiotics, curiously enough. There are well-founded doubts about the former as to whether they are able to pass through the stomach and colonise the intestine effectively. And, if they do, whether they are then able to display useful functions there. This is difficult to measure, among other things.
However, we do have the knowledge and clinical evidence that prebiotics, fibres, help both digestion and the survival of the intestinal microbiota. In other words, we know that prebiotics do have a positive effect on health, while we cannot say with complete and absolute certainty about probiotics yet.
They act very differently in the body
It may also seem obvious, but prebiotics enter through the digestive tract and are either consumed by the microbiota or they leave with the transit. That is how they interact with our body. However, probiotics are much more complicated, at least in theory. They must stay and colonize the epithelium of our digestive system. This process is much more complex and, on top of that, it is not ephemeral.
What’s more, it has other consequences, since it changes the existing microbial environment. Bacteria compete with other bacteria for the same resources, produce other substances and help digest in a different way. This is usually beneficial, but, as we will now see, it also has its risks. In short, prebiotics have nothing to do with probiotics in their way of acting.
Probiotics may pose some dangers
Without wishing to be sensationalist, the truth is that there are studies that point to a potential danger posed by probiotics in cases of immunosuppression. Organisms that belong to the microbiota are, in many cases, opportunistic pathogens. This means that, if everything goes well, they will do their job, but, if the environment gets out of control, they can take advantage of the situation to reproduce in an uncontrolled manner, causing an infection.
Although there is still a lot of evidence on this matter, it is true that their consumption is generally not recommended in cases of immune problems. On the other hand, there is also the suspicion that ingested probiotics could gradually replace some members of the normal microbiota. This would cause, in the long run, that we depend on their constant consumption to maintain a healthy microbiota and avoid deregulation.
What is a probiotic and what is it used for?
As we have already seen, probiotic foods are those that contain these microorganisms that are part of the microbiota and are intended to replenish or strengthen this population in our digestive system. This is important because our digestion does not only involve breaking down food with hydrochloric acid in the stomach.
Once the food bolus passes through this organ, it goes to the intestine where the microbiota continues to break down and help the intestinal microvilli to absorb nutrients. Therefore, we can say that probiotics help digestion. But, in addition, they also secrete other beneficial substances and help to properly control the microbiota.
What is a prebiotic and what is it used for?
Prebiotic foods contain dietary fibers that help provide substrate for these bacteria that inhabit our digestive system. These fibers are not digested in the stomach, so they pass through the intestine almost as they enter. Once there, the microorganisms digest them for us and absorb their nutrients to grow more and better, in addition to producing the beneficial substances we talked about.
On the other hand, prebiotics also have other positive effects. Fibre helps food to be digested better, reduces constipation, and produces a “matrix” that prevents the too-rapid assimilation of free sugars or even excess fats. The fibres in prebiotics are good for reducing metabolic and digestive pathologies and even cancer.