There’s a lot of hype around our gut and how it impacts our health. Especially now, when everyone is scrambling to optimize their immunity, lots of us are looking to take probiotics to strengthen our microbiome so we can fight off illnesses. But are probiotics worth your while?
We can’t talk about probiotics without first talking about the microbiome, which is the colony of bacteria, yeast, fungi, and even viruses, in our gut.
What is the microbiome?
Our gut is home to trillions of these microbiota. They actually live all over our body, but for the purpose of probiotics, we’re referring to the ‘gut’ meaning our large intestine, where most of our microbes reside.
The microbes can be beneficial, or harmful, and our aim is to have a good variety or ‘richness’ of good microbiota, and avoid ‘dysbiosis,’ meaning a large number of harmful ones.
Everyone has a different combination of gut microbes. The differences are geographic, too – Canadian microbes are different than what someone in, say, Africa will have.
Our ‘core native’ gut bacteria are determined early in life by things like our delivery method, gestation period, and if we were fed breastmilk vs formula.
But our personal microbiome can be affected throughout life by things like,
Diet
Exercise
Antibiotic use
BMI
In this amazing graphic from a 2019 study in Nutrients, you’ll see how different diets affect our gut bacteria. The type of bacteria in red and purple are considered harmful. Blue, green, and yellow boxes indicate beneficial bacteria types.
So, while your core gut bugs stay pretty much the same, the richness (number of bug types) and diversity (number of bugs in each type) of your microbiome can be mixed up by your health, and some of your lifestyle choices.
How does our microbiome affect our health?
So, we have these bugs in our gut, but why is it so important to make them happy?
We’re only at the tip of the iceberg with our knowledge of how the gut affects the different systems in our bodies. Mood, immunity, weight, hormones, inflammation – these are all being investigated for their ties to our individual microbiomes.
We believe that the gut has ‘crosstalk’ with different organs and systems in our body, which may modulate their health and function.
The gut-brain axis is an example of this – our gut bacteria are thought to send signals to the brain, which influence the central nervous system. For example, a 2016 study in the American Journal of Clinical Nutrition found that the consumption of short chain fatty acids – which gut bugs love – (via inulin, a dietary fiber) seemed to decrease hedonic eating behavior (aka eating past the point of fullness).
Of course, we know that people eat for all sorts of reasons besides the food tasting good. But, this was an interesting look at the hypothesis of how we nourish our gut, may impact our appetite.
What we do know is that dysbiosis – which is an imbalance of good versus harmful gut bacteria – is associated with a number of conditions and diseases, including IBS and possibly, mood disorders..
Does dysbiosis cause these things? Or, does the lifestyle of the host cause dysbiosis? We aren’t exactly sure. But it looks as though when gut bacteria go wrong, bad things happen.
Whatever the case, we do understand that having a good balance in our microbiome is what we should be aiming for. And many people do, by consuming probiotics.
What are probiotics?
Probiotics are live bacteria and yeasts that are similar to the good microbes in our gut. Probiotics can be found in some foods, and also in supplements.
Theoretically, when we consume these foods and supplements, the probiotics in them travel to our gut, where they join our microbiome and bolster it with good bacteria.
What do we NOT know about probiotics?
A lot, actually.
While probiotics have been shown by research to be effective for several conditions such as antibiotic-associated diarrhea, ulcerative colitis, and several conditions in infants such as necrotizing fasciitis, there are a lot of conditions and diseases that we just aren’t sure about.
We know that sometimes, people taking probiotics for the following conditions feel better. But benefits of probiotics are strain-specific, meaning there are certain strains that work for different condition.
For the following conditions, we don’t know which type of probiotic and how much of it is most effective, and often, studies looking at those things are very low quality:
Crohn’s disease
IBS
Diverticular disease
PCOS
Upper respiratory infections
It’s also important to know that the live bacteria in probiotic supplements and products need to be able to withstand the acidic environment of the stomach, in order to make it to your intestines.
When buying a probiotic supplement, make sure it’s made using technology that allows the probiotics to pass through the stomach unharmed.
If you’re looking for a probiotic but aren’t sure of the type you need, the Probiotic Guide app (Canada and U.S.) will help you. And AEProbio is a fantastic site that lists quality of evidence for whichever probiotic you’re looking at, and what you’re using to for.
What are the claims made about probiotics, and how do they stack up to the research?
Probiotics help our immune system.
Probably.
80% of our immune system is in our gut, so you’d think that with a healthy gut, would come a healthy immune system. But where do probiotics fit into the puzzle?
A good balance of beneficial bacteria in our gut helps maintain the integrity of the gut mucosa, or lining. When this doesn’t happen, pathogens (not food) may escape and cause illness.
While we do suspect that probiotics can stop this from happening in humans, we don’t have a lot of human studies – there are mostly animal and in-vitro (lab dish) ones – to establish proof.
Still, we know that immune cells in our gut are nourished by the metabolites produced by our microbiota.
When there is a disruption in our microbiome, say, by a low-fiber diet or a course of antibiotics, the immune cells in our gut don’t react the way they should to potential pathogens. This may lead to inflammation and decreased immune function.
In this situation, there’s enough information to connect the dots and say yes, probiotics may help our immune system.
But which type of probiotics?
It looks like different strains of lactobacillus and bifidobacterium have the greatest impact on immunity.
Yogurt has probiotics that can help your gut.
Not always.
First of all, it’s important to note that not all yogurts are probiotic. And a 2017 study in the journal Nutrients showed that a significant number of yogurts that were advertised as ‘probiotic’ didn’t actually have enough good bacteria in them to be effective for anything.
Look for yogurts that have ‘live and active cultures, and make sure your yogurt doesn’t have a ton of sugar, which IMO negates the benefit of having the probiotic in the first place.
It’s interesting to note that in Canada, yogurt must contain both Streptococcus thermophilus and Lactobacillus bulgaricus. But these are both destroyed by the stomach acid, rendering them useless for probiotic function. Yogurt companies can add in extra probiotics on top of these.
Sauerkraut, pickles, kombucha, and kimchi are great probiotic foods.
Not always.
If the brine or drink isn’t fizzing, the probiotic bacteria is dead. Heat kills beneficial bacteria, so if your pickles, sauerkraut, and kimchi have undergone high-temperature processing, it’s safe to say that they aren’t going to be a source of probiotics.
We also don’t know which bacteria strains and how much of them are in many foods that are advertised as ‘probiotic.’ Functional foods like crackers or chocolate with probiotics are just marketing woo woo.
While fermented foods may still be beneficial overall to our microbiome, they tend to be far lower in beneficial bacteria numbers than a supplement. So, eating them for the purpose of alleviating certain conditions, such as diarrhea, is probably a bad idea.
Probiotics are great for constipation and bloating.
True, maybe.
Assuming that your constipation and bloating is due to intestinal dysbiosis, then probiotics might help. Bifidobacterium is the type of probiotic that has been shown to be effective in that situation. B. Lactis and B. Reuteri have also been found effective for constipation.
But remember, constipation and bloating happen for various reasons, and many of them don’t involve gut bacteria.
Probiotics help IBS.
Maybe.
A 2019 review of studies found that multi-strain probiotics (supplements with not just one type of bacteria) seem to have the greatest effect, but overall, the results were inconclusive.
Probiotics help with weight loss.
Probably not.
While we suspect that gut bacteria may play a role in weight and energy homeostaisis, it’s far too early to say that probiotics can help with weight loss. This 2020 study seems promising, however.
People who are healthy should take probiotics anyhow.
Probably not.
There is no evidence showing that probiotics are necessary for healthy people. But you should be eating prebiotic fiber (prebiotics nourish our gut bacteria. They’re the food for probiotics!), which is one of our gut bacteria’s favorite meals, and fermented foods.
It looks as though diets high in saturated fats, sugar, and animal protein are bad for our microbiome. Diets high in plants – which are high in fiber that gut bugs love, as well as antioxidants – are good for our microbiome.
In short:
The jury is out in terms of probiotics’ effectiveness in a lot of conditions. But they’re generally safe, so feel free to take probiotics via supplements if you feel they’ll help you!
And remember: a diet high in plants and fermented foods can help, too.