Popping up in supplements, vitamins, drinks and even chocolate bars, probiotics are currently one of the buzziest health trends. With the growing interest in healthy eating, the global market for probiotics is expected to reach nearly $75 billion by 2025. But as it stands, the market has surpassed the science. According to Brett Finlay, microbiologist at the University of British Columbia, the future is certainly promising in terms of research to substantiate the probiotics hype. The problem is that currently, there isn’t enough clinical evidence to prove that probiotics promote good health.
That’s not to say that under certain and specific conditions, probiotics can’t help aid issues pertaining to the gut—but there’s a lot left to learn.
What are probiotics?
Probiotics are live microbes that can offer health benefits when consumed in sufficient quantities. (Prebiotics are essentially food for these microbes.) Microbes include bacteria, fungi, protozoa and viruses. Each of us host a colony of these in and on our bodies, which is known as the microbiome. The idea is that our gut microbiome—or our colony of gut bacteria—needs to have a balance between good and bad bacteria. If an imbalance occurs, probiotics are intended to correct this by introducing more good bacteria to the gut.
One of the issues, Finlay notes, is that probiotics often make no lasting impression on the gut. Instead, they’re flushed out. You can think of them as tourists, passing through your body. To have the continued benefit of probiotics, you have to keep taking them.
Where’s the science at?
Probiotics can help the immune system function properly and break down foods we can’t naturally digest, says Natasha Haskey, a registered dietician who specializes in nutrition for the gut microbiome. There is some clinical data that shows probiotics are helpful for some specific medical digestive issues, such as gas, bloating and diarrhea. And many other trials are currently underway. The website www.probioticchart.ca tracks products that have various levels of clinical probiotic evidence, as well as their specific uses.
For instance, yogurt has been shown to be helpful in the prevention of antibiotic-induced diarrhea, as well as the breakdown of lactose. In fact, many lactose-sensitive people can tolerate yogurt—likely because of the good bacteria.
While there is still a lot of research that needs to be done to prove the specific benefit of probiotic-laced products, they are completely safe to take. As Finlay says, “The good thing is they can’t hurt. But the not-so-good thing is there’s really nothing to prove that they actually work.”
What don’t we know yet?
Haskey says there’s no way yet to know what’s right for the average consumer, as researchers are still figuring out what a healthy microbiome should look like and what each specifc microbe does.
“For example, something we don’t know is whether it’s better to take a single strain or a multiple strain of probiotics. And the reason for that is everybody’s microbiome is a little bit different,” she says. “So you may have a bacteria in you that I don’t have.” Because of this, it’s difficult to create a catch-all vitamin or supplement.
What can we do in the meantime?
There are things you can do to “feed your gut,” or help maintain a balance. Haskey points to consuming a diet that’s rich in different types of fibre, as it keeps good bacteria alive and harmful bacteria at bay. Failing to feed those microbes can lead to harmful bacteria feeding on the mucus lining of our intestine, which creates inflammation to this critical protective barrier. When fiber is broken down into short-chain fatty acids—by microbes—they decrease inflammation and increase permeability, helping the body absorb nutrients.
“Research supports a diet that’s rich in different types of fruits and vegetables, not only because of the fiber that’s found in them, but there’s antioxidants that are critical to maintaining those good bacteria,” she says. Consuming a variety of fermented foods that perhaps contain probiotics also helps feed those good bacteria and add more of them into the body.
Haskey points to kimchi, a Korean dish of fermented vegetables. “They’ve done studies on kimchi around metabolizing glucose. It helps break down glucose or sugar in our body, so it would be beneficial for the prevention of Type 2 diabetes.” She also notes kefir, which has “been shown in a number of different types of scientific studies to have anti-inflammatory effects.”
In terms of avoiding certain foods, she cautions people to be wary of the types of fats they consume as well as encourages cutting highly processed foods from your diet.