In this article:

  1. The link between fungi and digestive distress
  2. Where to find S. boulardii

Let’s say you pop a probiotic every morning, drink kombucha instead of soda, and fill up on sauerkraut. That means your gut should be all good, right?

According to Dr. Mahmoud Ghannoum, PhD, EMBA, probiotic supplements actually may not be enough for some people—especially those who continue to experience uncomfortable symptoms like gas and bloating on the regular. The thing that could be holding them back from balanced digestion? They’re not getting a daily dose of good fungi. (Sexy, I know.)


“Often, people can get an overgrowth of bad fungi in the gut, similarly to how bad bacteria can take over,” he says. “In order to maintain a balance, you need to make sure you’re getting good fungi and good bacteria in the gut. Taking a probiotic is only fixing part of the problem.”

Dr. Ghannoum should know—he’s been studying the gut for 24 years and during that time has published over 400 peer-reviewed articles, been cited more than 16,000 times by other scientists, and has raised $25 million-plus in research funding. Oh yeah, and he’s literally the guy who coined the term “mycobiome“.

The link between fungi and digestive distress

Researchers—including Dr. Ghannoum, but also others he has no connection with—studied the guts of healthy people and those with Crohn’s disease, a chronic inflammatory condition that affects the lining of the digestive tract. They all noticed the same thing in the Crohn’s patients: an influx of candida, a specific fungus strain. “Researchers saw the same thing in people with IBS,” Dr. Ghannoum says.

Ready for the gross part? Fungi in the gut can be 10 times larger in size than bacteria. No wonder they can cause some pretty unpleasant problems.

To bring the gut back to balance, says Dr. Ghannoum, you need good fungi to overtake the candida. He recommends a yeast strain called S. boulardii, which is present in some probiotics as well as available as a solo supplement.

Where to find S. boulardii

The hard part about getting enough good fungi for the gut is that it’s almost impossible to consume the amount you need through whole foods. “Some foods have fungus, like French cheeses, but it’s the wrong strain,” Dr. Ghannoum says. S. boulardii is present in some plants, like lychee and mango, but you would have to eat a lot in order to reap any benefits.

That’s why—full disclosure—he recently formulated a supplement with bacteria, fungi, and a digestive enzyme all in one capsule. But there are also other options on the market containing just S. boulardii, so his is definitely not the only way to go (though we recommend it).

The bottom line is, if you aren’t experiencing any digestive problems at all, your gut is likely balanced and you don’t need to add another supplement. (Congrats!) But if your body is still sending out distress signals, the reason could be that bad bacteria and fungi are running amok—and addressing this issue could finally be the fix you’ve been looking for!

Editor’s note: This post has been updated for relevancy. Its first publish date was April 21, 2019.