Do or don’t: why taking pre- and probiotics deserves thinking twice?

probiotic prebiotic health microbes gut microbiome

The search of the ultimate health-beneficial pill is going on with full speed for decades, if not centuries. One of the avenues science and medicine are exploring, are the pre- and probiotic formulations, supposed to improve our digestive system health and with it – our over-all well-being. 

This time we talk “good guys” unlike the previous bacterial post. Many bacteria live in our bodies in a peaceful and even beneficial manner. But is there any truth to trying to add extra of the good guys in a pill form? Here’s some of the science on this… 

Statement beyond proof?

Nowadays, it is extremely hard to prove the health benefit of anything really. In the European legislation, for a product to have the right to the claim that it promotes health, it should be supported with evidence from medical trials. There should also be scientific evidence support from trials that prove the beneficial health effect in healthy individuals too.   

This video gives a nice and simple idea of how such trials work and why it can be hard to conduct them the right way. The point is that such intervention trials are absolute key to drug, food and supplements development and consumer safety.

It might seem frustrating, but it is done in order to prevent countless products popping up on the market, boasting completely unsupportable claims, essentially tricking consumers to purchase them in the hope that they will improve their quality of life. 

Some regulators, manufacturers and even some consumers believe that such hurdles are only crippling smaller companies and start-ups to reach the consumers. The legislative hoops for manufacturers are out of the abilities of many to jump through. But whether or not this is always a bad thing, is not on me to decide or conclude in this blog post. However, I suggest reading the publication of the European Food Safety Authority (EFSA) on the matter to try and understand what, who, how and why the rules are what they are.

What is in a pre/probiotic

Since often you don’t need a prescription to buy either pre- or probiotics, people tend to use them interchangeably. And that is exactly because of the generic health benefit both are known for. However, this generic view is a major misunderstanding of the needs of your body.

So lets take a step back and review what we are talking about when we talk beneficial microbes:


bacteria gut happy good probiotic

Probiotics are alive microorganisms, which are thought to have beneficial influence on  health, especially on the digestive system. 

The general belief is that probiotics are able to replace or restore the balance of good gut microbes in the intestines. This way, the general health of the individual is improved in the long term.

Often, probiotics are prescribed together with an antibiotic treatment. This is necessary since antibiotics against pathogenic bacteria often kill some of the good gut microbes too. That’s why after an infection treated with antibiotics, you need to replenish the numbers and the correct species of gut microbes. 


prebiotics nutrition food health

Prebiotics are very different from probiotics.

The key difference is that while probiotics are living organisms which promote health, prebiotics are compounds which promote the growth of probiotic bacteria.

Prebiotics can be specific nutrients, carbohydrates, vitamins, amino acids or even parts of dead microbes, which are useful for the life of the bacteria to which they are supplemented. 


How do scientists think pre/probiotics work?

Here is a very detailed scientific review, which compiles the different scientific evidence and the types of microbes scientists think are considered “good”. In general, beneficial microbes produce vitamins, amino acids and other organic molecules, which the human body cannot make on its own. And of course, since different bacteria have very different metabolisms to one another, they also produce different beneficial molecules that the human body can utilize. 

Exactly because bacteria are so different, they also prefer “eating” different things too. So in order to keep a complex society of gut microbes happy, you’d need to supplement them all with the food they are most efficient with. This does not necessarily mean the food they grow the fastest on. Often, bacteria produce the most valuable compounds as part of their secondary metabolism – when they are not actively growing or multiplying. The following image illustrates this very well:

microbes growth metabolism primary secondary probiotic prebiotic kinetics
Slide extracted from here (click the image to view the whole presentation)

This mean that depending on the probiotic, one would need to take specific prebiotic too. And even if you gut microbes population is fine as is and your don’t need probiotics, if you want to make them a specific compound more than another, you’d have to supply them with the correct nutrients to boost that pathway from their metabolism. This can be done either by providing them with different prebiotics, or by altering your own diet to meet their requirement as well as yours.

What might be wrong with taking either pre- or probiotics?

Well intrinsically, there’s nothing bad with taking either pro- or prebiotics. But…

There is always a “but…” in science – that’s how you know it’s real! 

If you have a weakened immune system due to a disease or an autoimmune condition, taking any type of live microorganisms is a bad idea. Even the ones considered to be generally good for people can hurt you when your immunity is low. Immune compromised people are very prone to infections and even good bacteria in too great a number can disrupt the balance of the body. And when a body is already fighting a disease, the last thing it needs is more bugs.

More questions than answers about our gut microbe populations

Talk about balance… Even today, no scientist, nor a medical practitioner really knows what the healthy microbiome looks like. We know that certain microorganisms are good and others – not, but science actually knows very little about the exact composition, ratios and sub-populations of microbes that compose the optimal microbial tenants of our gut.

On one hand, it is actually surprisingly hard to establish the exact composition of the gut microbiome. Since different microbes live in different parts of the gut, and some we don’t even know how to grow in the laboratory conditions, it can be tricky to study and properly count them.

On the other hand, many scientists nowadays argue that the healthy microbiome is actually an extremely individual feature for each one of us. This means that we cannot possibly create a standardized pre- or probiotic product suitable for everyone’s needs. Some research even shows that our individual genetics does influence the specific make up of our gut microbiome.

So, unless we are looking at something as refined as personalized nutrition and medicine, science cannot claim with sufficient certainty that just any off-the-shelf pre- or probiotic is the right thing for you. And the food you eat is also extremely important. You can take all the health promoting microbes you want, but if you live on sodas, sugar and fat, even they won’t help you remain healthy. 

Substandard products flooding the markets

What is even worse, such health promoting products are prime value and thus a major target for counterfeiting. Even if genuine, the formulation of many pre- and probiotic products could render them useless quickly.

As already mentioned, probiotics need to be alive to be able to colonize your gut again. Which means that stabilizers, additives and storage conditions are extremely important in order for a probiotic to remain remotely efficient.

Storage and chemical properties of prebiotics are also important for their effect. Some bio-molecules acting as prebiotics are light-, temperature- or humidity- sensitive and can easily lose their properties if they are not prepare, packaged and stored properly. 

What should you do?

As with everything – try and get reliable information from a trustworthy source before you purchase any concoction which claims to be health-promoting.

If you have a medical condition, which you believe warrants the use of either pre- or probiotics, consult your physician.

If you are healthy and feel the need for help to remain so, talk to a specialist nutritionist.

And if you are just hoping that with the help of gut-microbe-promoting-products you can restore a healthier you by say getting some help with losing weight, or for an acne free skin, you can always talk to the obesity clinic near you, or the dermatologist in the nearest medical center.

They all should have access to the latest science research and a good overview of which product should be best suited to help your other efforts. Because it is highly unlikely that a single pill containing good microbes or food for them would be individually able to solve all your health issues.

Recently I had to take probiotics after an antibiotic treatment. I don’t know if it made a huge difference, but then again the antibiotic I had to take was a narrow spectrum one (meaning that it would kill a narrower range of bacterial species). So may be my gut microbes did not suffer as badly as if I had taken a broad spectrum one (one that can harm many different bacteria). How about you? When was the last time you took either pre- or a probiotic? How did you decide to do so? And how did you feel after?

probiotic prebiotic health microbes gut microbiome

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