Jacob Schor ND, FABNO
December 1, 2009
The French scientist Henri Boulard is credited with isolating Saccharomyces boulardii from lychee and mangosteen fruits in 1923. Boulard had observed people chewing lychee and mangosteen skins in order to control cholera symptoms.
This particular strain of yeast, obviously native to the tropics, is related to but is distinct from regular baker’s yeast, Saccharomyces cerevisiae. S. Boulardii has become popular as a nutritional supplement in recent years and though a yeast is still often called a probiotic; like acidophilus bacteria, it also maintains and restores normal flora to the small and large intestine and improves immune function.
S. boulardii will quickly colonize the gut within three days of consumption but it doesn’t survive in the intestines very long; it will be completely gone in about five days. In the process though it appears to crowd out other unwanted bacteria and yeast. Probably because it is a tropical yeast, it only grows at a relatively high temperature of 37°C.
The National Library of Medicine’s search engine, PubMed, currently lists 302 papers on S. boulardii, far more than you want to read about here.
Sorting through them, six main effects S. boulardii are described:
1. Protection against gut pathogens
2. Moderation of immune responses
3. Decreased inflammation
4. Inhibition of bacterial toxin action
5. Enhanced function of gut enzymes and nutrient transport mechanisms.
6. Increases gut immunoglobulin, secretory IgA.
Let’s just look at some studies published in the past year.
A paper from Spring 2009, discussed the mechanisms by which S. Boulardii improves digestive function. Two papers published in early summer 2009 describe using S. boulardii to treat children with amebic dysentery in combination with the drug metronidazole. The first in the Turkish Journal of Pediatrics found it safe to use in children. The second reported that the combination of drug and yeast significantly shortened the time to recovery. The big uses up to this time had been to treat travelers diarrhea and antibiotic caused diarrhea and gastritis. The same team of Turks had published an article a few months earlier, in March, suggesting the use of S. boulardii in treating acute pancreatitis because it decreases bacterial translocation and lung injury. Another June article describes a well-known use for S. Boulardii, treating Clostridium difficile infections. Even the Merck Manual recommends S. boulardii for this use. Harvard researchers had a paper published in September describing the mechanisms by which S. Boulardii may prevent colon cancer. Another paper tells us this yeast decreases mucositis and other damage caused by the chemotherapy drug irinotecan; we probably should consider using it more often with cancer patients. A very recent paper, December 2009, describes how S. Boulardii inhibits the growth of Candida albicans and also decreases the virulence, that is the nastiness, of this often-problematic yeast. Another paper, this one from UCLA published in October 2009, describes S. Boulardii’s anti inflammatory effects as an explanation for why it is useful in treating inflammatory bowel disease.
One of the main fascinations with this yeast is that it appears to calm down hyperactive immune function. In an April paper German researchers explain how S. boulardii decreases the secretion of key pro-inflammatory cytokines such as tumor necrosis factor-alpha and interleukin (IL)-6 while increasing of anti-inflammatory IL-10. S. boulardii also inhibits the proliferation of naive T-cells and modulates dendritic cells.
I took Latin in high school and never learned French. This is my excuse for the many years that I misunderstood what this yeast was. I mistakenly thought the word boulardii had something to do with the French word, ‘Boulan,’ which means, ‘Bakery.’ Thus I mistakenly assumed that S. boulardii was a form of baker’s yeast.
Under this false impression, I conducted an interesting experiment last week. I used S. boulardii to bake bread.
Over the past three years there has been a quiet revolution in home baking over a ‘new’ recipe for ‘No Knead Bread.’ I came late to the party but over the past month have been catching up, churning out these ‘no-knead’ loaves regularly. Most of the breads have emerged tasting so good that I’m dumbfounded. Mark Bittman of the New York Times wrote about this recipe in November 2006: it was my first exposure to this business. It’s worth reading his article and then following the link to watch a demonstration on YouTube:
Anyways, under the delusion that S. boulardii was just overpriced baker’s yeast, I opened a few capsules and used it as my baking yeast last week. It certainly does need high temperatures to grow; at room temperature it did nothing, in fact I thought it was dead, but when the dough was left to rise on the hot radiator, it woke up and rose rapidly. It created an excellent loaf structurally. Admittedly though the flavors were not as well developed as those achieved using S. cervesiae, regular baker’s yeast. Still it worked surprisingly well all things considered.
Obviously by the time bread is fully baked and comes out of the oven, the yeast inside it is quite dead. Yet could my no-knead ‘Boulardii Boulan’ still have some health benefits?
There are studies on other strains of probiotic organisms suggesting they are of benefit whether the bugs are, ‘dead or alive.’ One example is VSL #3, a high dose strain of lactobacilli sold in pharmacies and used to treat ulcerative colitis. A study done by Italian researchers and published Summer 2009 examined the effects of VSL #3 on immune function especially focusing on immune-modulation and how T-helper cells were affected. In this study, dead VSL #3 worked just as well as the live bugs did. There was a similar study several years ago but I can’t find it at the moment. Research interest on VSL #3 appears to be pretty hot. There are more than a dozen new papers in the last 12 months. I’ve used VSL #3 for making homemade yogurt. Another one of those home experiments I am prone to trying. It worked, but like my boulardii bread, it wasn’t the best tasting yogurt ever eaten. Still, it probably had health benefits above and beyond store bought yogurt.
Here’s the VSL #3 company’s website: http://www.vsl3.com/about.asp
[The company does not appear to be updating their website with this newly published research. Amazingly even Wikipedia doesn’t have an entry for VSL #3. Whoever is in charge of marketing this product must be slacking off.]
There is an interesting article in the October 2009 issue of In Focus a newsletter put out by a supplement company. Admittedly not peer reviewed but interesting nonetheless. You’ll notice that some of my information in this article was copied from their article on Saccharomyces boulardii on page 10. What’s more interesting though is the protocol suggested by Michael Ash on page 2 for treating Atypical Depression. He has a theory that many cases of depression are triggered by inflammatory cytokines triggered by atypical gut flora. He suggests S. boulardii as the first phase of treatment in restoring normal gut function and treating this variant of depression.
I’ve just about finished eating my loaf of no-knead ‘boulardii bread.’ I don’t think I’m feeling any happier yet. Still this might be an interesting way to increase Secretory IgA and do all sorts of other nifty things to improve one's health. This could be some real Wonder Bread.
That In Focus newsletter is available at:
This Denver Naturopathic News letter is posted on our website and as usual the online version contains abstracts of all studies cited:
Here’s the recipe from the Times for No-Knead Bread:
Published: November 8, 2006
Adapted from Jim Lahey, Sullivan Street Bakery
Time: About 1½ hours plus 14 to 20 hours’ rising
3 cups all-purpose or bread flour, more for dusting
¼ teaspoon instant yeast
1¼ teaspoons salt
Cornmeal or wheat bran as needed.
1. In a large bowl combine flour, yeast and salt. Add 1 5/8 cups water, and stir until blended; dough will be shaggy and sticky. Cover bowl with plastic wrap. Let dough rest at least 12 hours, preferably about 18, at warm room temperature, about 70 degrees.
2. Dough is ready when its surface is dotted with bubbles. Lightly flour a work surface and place dough on it; sprinkle it with a little more flour and fold it over on itself once or twice. Cover loosely with plastic wrap and let rest about 15 minutes.
3. Using just enough flour to keep dough from sticking to work surface or to your fingers, gently and quickly shape dough into a ball. Generously coat a cotton towel (not terry cloth) with flour, wheat bran or cornmeal; put dough seam side down on towel and dust with more flour, bran or cornmeal. Cover with another cotton towel and let rise for about 2 hours. When it is ready, dough will be more than double in size and will not readily spring back when poked with a finger.
4. At least a half-hour before dough is ready, heat oven to 450 degrees. Put a 6- to 8-quart heavy covered pot (cast iron, enamel, Pyrex or ceramic) in oven as it heats. When dough is ready, carefully remove pot from oven. Slide your hand under towel and turn dough over into pot, seam side up; it may look like a mess, but that is O.K. Shake pan once or twice if dough is unevenly distributed; it will straighten out as it bakes. Cover with lid and bake 30 minutes, then remove lid and bake another 15 to 30 minutes, until loaf is beautifully browned. Cool on a rack.
Yield: One 1½-pound loaf.