How probiotics support the immune system and better digestion
Your gut does a lot more than just digest your dinner. Your digestive tract is also home to most of your body’s immune defenses: roughly 70% of your immune system exists in and along your digestive tract. Even the gut itself is an important part of your immune defenses: it acts as a barrier wall to keep invaders out of your bloodstream1. So keeping the gut healthy goes a long way in ensuring a healthy immune system.
Bacteria and your immune system
The trillions of bacteria living in your gut are constantly interacting with your digestive and immune systems1,2. Gut bacteria are an important factor in how our immune systems develop from birth; research tells us that animals without gut bacteria have very different immune responses than ones with a normal gut environment1,3.
How can something so tiny have such a huge impact? It’s because in order to survive in the body, our gut bacteria have developed sophisticated ways of communicating with their world. Gut bacteria are able to protect the health of the gut by fighting off bad bacteria, which they do by competing for space and resources, in addition to making substances like bacteriocins that kill off harmful bugs2. As part of their normal metabolism, some gut bacteria create metabolites such as short chain fatty acids that can decrease damaging inflammation, alter production of immune cells or strengthen the immune defense barrier1,2,5. If gut bacteria can do all this, can a probiotic do the same?
How do probiotics work?
Probiotics are beneficial bacteria, often part of the natural human gut microbiome, that have the power to influence our health2. Probiotic bacteria can be found in small amounts in fermented foods, such as yogurt, sauerkraut and kombucha. You can also find higher doses (typically in the billions of live cells) in supplement form.
Research has found that certain probiotics can influence the health of the human gut and immune systems, acting much like our own resident bacteria do2,3. For example, Bio-K+ probiotic pills have been shown to effectively fight off the bacteria that contribute to antibiotic-associated diarrhea, as well as C-diff-associated diarrhea4. Research has also shown potential for probiotics to have a positive impact on the immune system, whether by creating a stronger gut barrier, increasing beneficial immune cells or even decreasing risk of cold and seasonal flu2,3,5.
How to choose an effective, science-based probiotic
While the science of probiotics is promising, this does not mean that all probiotics will be effective. There is a big gulf between what is happening in the research and what you find on store shelves. Many products on the market do not conduct any clinical research, meaning that you can’t be sure that what you are buying is effective. What’s more, because probiotics are living organisms, each strain – or combination of strains – may have different potential effects. You can’t take the research on one probiotic and apply it to another.
It can make choosing a probiotic feel a bit overwhelming – but it doesn’t have to be. Instead, tools like the Clinical Guide to Probiotics (www.usprobioticguide.com) help take the guesswork out of choosing a probiotic. The guide outlines which probiotics have evidence to support their use, and which uses they are best suited for.
Our gut bacteria play an important role in our digestive and immune wellness. While there is much more to learn about how probiotics influence our health, there is great potential for probiotics to become an integral part of our self-care habits so always be sure to talk to your doctor, pharmacist or dietitian about whether probiotics are right for you.