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Essential Guide To Saccharomyces Boulardii Probiotic Yeast

Essential Guide To Saccharomyces Boulardii Probiotic Yeast

Saccharomyces boulardii is a probiotic yeast with proven benefits for human health. Discover how S. boulardii can boost your gut health and why most online health claims are nonsense.

S. boulardii is a tropical yeast that was discovered in Asia by a French scientist (Henri Boulard) in 1920, who noticed that people drinking tea made from the skins of tropical fruit didn’t fall ill during a cholera outbreak – a potentially serious infection of the small intestine.

Now Saccharomyces boulardii is a recognised probiotic that can help with IBS, Crohn’s disease, diarrhea, and a range of gastrointestinal infections. Officially known as Saccharomyces cerevisiae boulardii, it is a subspecies of the Saccharomyces cerevisiae (baker’s yeast).

There are many different probiotics with Saccharomyces boulardii. Some are enhanced with prebiotics (MOS), and others are mixed with probiotic bacteria. Discover the benefits of this probiotic yeast and what health conditions it can help with in this article.

Table of contents

What is Saccharomyces boulardii?

Even though the majority of probiotics are bacterial, some yeasts are good for your health because they are able to combat infections and reduce symptoms, like Saccharomyces boulardii, and S. cerevisiae. That's why they're probiotic.

Probiotics are “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host”

Yeasts are microscopic fungi (tiny mushrooms) that make their home on and in living things. Most of the time, yeasts are harmless to humans, but sometimes they can cause infections or even make you drunk – a very rare health condition called auto brewery syndrome.

Saccharomyces boulardii side effects are rare. However, if you have any symptoms of an allergic reaction (swelling or hives), you should discontinue treatment and seek medical help.

☝️TIP☝️ Find out how to keep your gut healthy with the Atlas Microbiome Test and get personalised prebiotic food lists each week.

Saccharomyces boulardii probiotic benefits

  • anti-toxin: it can stop toxins produced by infectious bacteria that make people ill.
  • antibacterial: S. boulardii can directly stop infectious bacteria from reproducing.
  • microbiome-friendly: this yeast supports normal gut bacteria that don’t make you sick.
  • anti-inflammatory: it helps prevent inflammation of the gut lining so it works better.
  • immune health: S. boulardii helps regulate immune responses.
  • nutrients: it helps restore short-chain fatty acid production that keeps the gut healthy.

The benefits of Saccharomyces boulardii mainly apply to your gut where it works to protect against inflammation. It also helps out your immune system, promotes the activities of good bacteria in your gut, and even deters opportunistic microbes that could make you sick.

Many Saccharomyces boulardii benefits come from its ability to stop pathogens and their toxins from infecting the gut, which often results in diarrhea and inflammation.

Infections also hurt the good bacteria in the human gut, but studies show that S. boulardii can help them recover so they can get back work, producing important short-chain fatty acids that keep the gut lining healthy.

☝️FACT☝️It is recommended that people with yeast allergies or who are taking antifungal medication don’t use S. Boulardii supplements.

Saccharomyces boulardii lyo CNCM I-745

The strain of yeast probiotic Saccharomyces boulardii is officially known as Saccharomyces boulardii CNCM I-745. The term lyo does not refer to the yeast, rather it is an abbreviation of lyophilisation (freeze-drying), a technique used to stabilise and protect probiotic supplements.

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One review of S. boulardii CNCM I-745 shows that it can help the gut microbiome find stability and prevent diarrhea caused by dysbiosis (an imbalanced gut microbiome). One of its main contributions to gut health is helping good bacteria, which make short-chain fatty acids.

Saccharomyces + MOS

Saccharomyces boulardii MOS probiotics are supplements that contain S. boulardii and Mannan-Oligosaccharides (MOS), which are complex carbohydrates derived from S. cerevisiae yeasts.

MOS are prebiotics, meaning that they are a source of energy for good bacteria in the gut. Plus, they can block pathogenic bacteria (E. coli and Salmonella) and increase probiotic Lactobacillus levels, which are essential for a healthy gut.

Saccharomyces boulardii MOS side effects are rare. However, you should not take a probiotic containing Saccharomyces boulardii if you are allergic to yeast or using antifungal medication according to Drugs.com.

Proven benefits of a probiotic with Saccharomyces boulardii

Common bacterial probiotics are Lactobacillus, Bifidobacterium, and Lactococcus.
Lactobacillus, Bifidobacterium, and Lactococcus are famous probiotics

Reliable and good quality evidence demonstrates that patients with these gastrointestinal infections have benefitted from treatment with probiotic Saccharomyces boulardii:

Antibiotic-associated diarrhea 7-14 days treatment with S. boulardii is effective at preventing diarrhea caused by antibiotics.
H. pylori Saccharomyces boulardii may help reduce the side effects of standard triple therapy (which includes antibiotics) for H. pylori infections.
Traveller’s diarrhea When taken in advance and regularly while travelling, Saccharomyces boulardii can prevent traveller’s diarrhea.

Potential benefits of Saccharomyces boulardii

Small studies using a probiotic with Saccharomyces boulardii showed some benefits for these conditions, but researchers warn that stricter clinical trials and larger patient groups are needed to validate these results:

IBS, diarrhea type Saccharomyces boulardii can help lower episodes of diarrhea and improve IBS symptoms.
Crohn’s disease Small studies show that S. boulardii can help prevent relapse for patients in remission.
Ulcerative colitis A small study shows that it helped patients who don’t tolerate steroid medication very well.
C. difficile infections Probiotics containing Saccharomyces boulardii helped reduce recurrence of C. diff when used alongside antibiotics.

Online myths about S. boulardii

This doctor debunks some very common health myths (by Wired)

The internet is a place where people can share ideas and thoughts. It’s also a place where myths and false information proliferate. So we’ve dedicated this section to debunking myths about Saccharomyces boulardii so you don’t waste your money on supplements for no reason.

The Saccharomyces boulardii Candida myth

Candida yeasts are the most common cause of fungal infections (medical term: candidiasis). For example, thrush is caused by a Candida overgrowth in the mouth, and women can get yeast infections if Candida grows out of control in the vagina.

However, Candida yeasts are a natural part of the body’s ecosystem. They live on and inside your body (the same way bacteria do) and they are generally harmless, unless something upsets this symbiotic relationship.

Does saccharomyces boulardii cure candida?

Currently, there is no evidence to suggest that Saccharomyces boulardii is effective for Candida infections. One 2019 study (not in humans or animals) shows that S. boulardii may help prevent non-albicans Candida yeasts from sticking to surfaces, but it doesn’t work if the surface is already colonised.

Even though many online articles suggest that Saccharomyces boulardii can make Candida die off, the evidence is very weak. Some studies looking at Saccharomyces boulardii and Candida are 30-40 years old, and the others were conducted in mice and on incubation plates.

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Plus, these claims are directly contradicted by a 2011 study where researchers showed that S. boulardii supplements did not prevent Candida albicans infections in mice. Saccharomyces boulardii doesn't treat yeast infections either.

☝️The bottom line☝️ Don’t believe the Saccharomyces boulardii for Candida hype. If you are concerned about a candida overgrowth, consult a doctor who can order proper tests.

Saccharomyces boulardii and SIBO

Small Intestinal Bacterial Overgrowth (SIBO) is a condition in which bacteria grow out of control in the small intestine, resulting in a range of non-specific digestive symptoms, such as bloating, diarrhea, nausea, and abdominal pain.

Despite online claims about a Saccharomyces boulardii SIBO cure, there is currently very little evidence to support this. Before taking S. boulardii for SIBO, consult your doctor about testing and a medically-appropriate treatment plan.

Saccharomyces boulardii and weight loss

One study in mice showed that S. Boulardii Biocodex (the first S. boulardii to be isolated, currently supplied by Biocodex) could reduce body weight gain, fat mass, and liver fat.

☝️FACT☝️ You are not a mouse, and until this is verified in large human studies, don’t waste your money on Saccharomyces boulardii for weight loss.

Saccharomyces boulardii and constipation

Even though S. boulardii may help alleviate diarrhea in patients with IBS, there’s no evidence that Saccharomyces boulardii can treat constipation. This claim first appeared in a 1918 study about the benefits of S. cerevisiae for constipation.

Saccharomyces boulardii and acne

Although some websites suggest that Saccharomyces boulardii works for acne, there is no evidence to suggest that this is true. The possible source of confusion is a scientific article from 1918 that suggests S. cerevisiae can help patients with acne.

The final word on S. boulardii

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Not all probiotic marketing claims can be trusted

Saccharomyces boulardii is a popular probiotic yeast that’s especially good for helping people recover from diarrhea. One of the best things about S. boulardii is that it cares for the good bacteria in your gut, which support your digestive and overall health.

However, many online claims are simply untrue and there is no evidence to support them. So please, don’t buy expensive S. boulardii supplements for acne, weight loss, SIBO, or Candida, because they probably won’t work.

Leigh Stewart
Leigh Stewart Head of Atlas Biomed content, trained chef and avid fermenter of edible bacteria.

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