Saccharomyces boulardii and Lactobacillus acidophilus are both microscopic. They both have positive health effects when consumed live. They've both been called probiotics and have been added to foods to bolster their nutritional content. But Saccharomyces is a form of yeast and Lactobacillus is a bacterium.
Bacteria
Bacteria are single-celled organisms. Structurally, bacteria are different from yeast in that membranes do not bind their nuclei and other organelles. Bacteria can survive both inside and outside the human body. You probably associate bacteria with illness. It's true that infectious diseases, both serious and mild, can be attributed to bacteria, but these tiny microbes also have beneficial effects to humans.
Vaccines have been created via collaborations between human scientists and bacterial cultures. Most often, however, when you hear the phrase "good bacteria," it's in reference to the probiotic strains found in foods like yogurt. Many different strains of probiotic bacteria have been identified.
Yeast
Yeast is a single-celled fungus. It has a cell structure that includes a membrane-bound nucleus. The overgrowth of some types of fungi causes human ailments such as athlete's foot, jock itch or candidiasis.
Yeast isn't inherently bad, though. "Good" yeast is used for a number of things, such as baking food and supplying vitamin B-12. In terms of probiotics, only one strain of yeast has been widely recognized as having probiotic effects -- Saccharomyces boulardii.
Benefits of Probiotics
Probiotics are used to bolster the natural colonies of microbes that inhabit your gastrointestinal tract. Factors such as antibiotic use can sometimes deplete these colonies, and leave your digestive tract susceptible to invasion by harmful pathogens. The use of probiotics has been shown to help a range of gastrointestinal disorders such as lactose intolerance, antibiotic associated diarrhea, traveler's diarrhea and peptic ulcers due to Helicobacter pylori infection.
Strain Specificity
You cannot take just any probiotic supplement and expect it to deliver the effects you desire. The effects of probiotics vary from strain to strain. And although Saccharomyces boulardii yeast has been the subject of more studies than most other probiotics, Marcia Buck of the University of Virginia Children's Hospital notes that additional research is needed to confirm its safety and effectiveness. Consult your doctor before taking probiotic supplements.
References
- "Pediatric Pharmacology"; Saccharomyces boulardii as a Probiotic for Children; Marcia L. Buck; July 2009
- MedlinePlus: Saccharomyces boullardii
- "Functional Food Reviews"; How Do We Know When Something Called "Probiotic" Is Really a Probiotic? A Guideline for Consumers and Health Care Professionals; Mary Ellen Sanders; 2009
- USProbiotics: Probiotic Basics
