Saccharomyces boulardii:
A Unique Probiotic with Immune - Modulating Ability
By Stephen Levine, Ph,D.

Saccharmoyces boulardii (S. boulardii) is the best researched probiotic yeast, with nearly 300 peer-reviewed studies. Isolated from litchi fruit in the 1920s, S. boulardii colonizes the gut within three days of oral consumption and disappears from stool within five days after discontinuation. New research confirms it as a first choice for preventing and treating traveler's diarrhea, antibiotic-associated diarrhea, and C. difficile colitis, as well as helping improve Crohn's disease, ulcerative colitis, and irritable bowel syndrome. Studies have shown that S. boulardii:

• Protects against gut pathogens
• Modulates the immune response
• Decreases inflammation in a wide range of disorders
• Inhibits bacterial toxins
• Enhances the gut's natural enzymes and nutrient transporters
• Increases the most important gut immunoglobulin, Secretory IgA

Hello Good Yeast, Goodbye Diarrhea

It's widely known that S. boulardii (Sb) helps prevent and treat antibiotic-associated diarrhea (AAD) caused by pathogens such as Clostridium species, Staphylococcus aureus, Klebsiella, Candida, and Salmonella. Mainstream as well as integrative medicine doctors often prescribe it along with antibiotics. "Given the broad range of protective effects in multiple gastrointestinal disorders," wrote researchers from Harvard Medical School in a 2006 study, "we hypothesize that Sb modulates host signaling pathways involved in intestinal inflammatory responses." Indeed, the researchers found that Saccharomyces boulardii blocks activation of inflammatory molecules called kinases.

Other new research confirms the yeast's potency in preventing diarrhea. S. boulardii slashed the risk of Other new research confirms the yeast's potency in preventing diarrhea. S. boulardii slashed the risk of antibiotic-associated diarrhea by nearly 2/3 in a study of 269 children with ear or upper respiratory tract infections. The children were given antibiotics plus 250 milligrams of S. boulardii twice daily or a placebo. Only 8% of S. boulardii children had diarrhea, compared to 23% taking a placebo. In another study on 151 hospitalized patients, only 1.4% of those who were given S. boulardii in addition to antibiotics had diarrhea, compared to 9% on placebo. In addition, C. difficile toxin was found in two of the placebo patients and none of the S. boulardii patients.

S. boulardii also protects against the devastating and difficult-to-treat C. difficile colitis. When 124 patients on high dose vancomycin (antibiotic) for C. difficile colitis were given S. boulardii, rates of recurrence plummeted from 50% to 16.7%. A 2006 meta-analysis found that various probiotics help prevent antibiotic-associated diarrhea, but only S. boulardii prevents and treats C. difficile-associated diarrhea.

S. boulardii is effective in preventing traveler's diarrhea as well, of which 80% is caused by E. coli, Shigella, or Salmonella species. A study of over 1,000 travelers found that rates of diarrhea dropped from nearly 40% to 29% when travelers started taking S. boulardii at 1,000 milligrams daily, five days before and for the duration of their trip.

S. boulardii is uniquely able to stimulate Secretory IgA (SIgA), our first line of defense against invading microbes, and is key to maintaining intestinal mucosal homeostasis and integrity. It is the main immunoglobulin found in mucus, tears, saliva, vaginal fluid, and secretions from the intestine and lining of the lungs. It resists degradation by enzymes, and provides profound protection against pathogens.

S. boulardii is anti-inflammatory; it decreases the expression of inflammatory cytokines (chemical messengers) including interleukin 8 (Il-8), IL-6, IL-1b, tumor necrosis factor alpha (TNF-a), and interferon gamma (IFN-y). It can also reduce inflammation by suppressing nuclear factor-kappa b (NF-kB), which is activated during infection.

S. boulardii restores intestinal homeostasis by decreasing inflammation, stimulating the immune system, and acting as an antimicrobial. Be sure to keep this on hand when traveling, especially to a foreign country, and always add to an antibiotic treatment to help maintain intestinal balance.