Though it may surprise some of you, our bacteria actually outnumber our human cells by a factor of 10 to 1. These bacteria play an important role in the function of the human body–particularly involved with metabolism and nutrition.
Most probiotics contain various strains and species of bacteria–though there are some exceptions including certain types of yeast.
Do Probiotics Work?
Among other roles, bacteria play an important role in the following:
- synthesize compounds such as vitamin K and B vitamins
- break down cholesterol
- digest polysaccharides that would otherwise be unavailable for energy use
- contribute to host defense / play a role in the immune system
- inhibit colonization of pathogenic bacteria
- produce ‘bacteriocins‘ which are small molecular weight peptides which kill other pathogenic bacteria
In short, our commensal microbes coexist with us in a symbiotic relationship. It almost makes you want to give them a bug hug–if you only could.
What Are Probiotics?
The most common and cited definition of probiotics is sourced from the United Nations and World Health Organization:
“live microorganisms which, when administrated in adequate amounts, confer a health benefit on the host”
Sounds simple enough, so what’s with all of the confusion? To start off with, different sources of probitiocs whether they be from yogurt or dairy products, dietary supplements, or other related products contain different species, strains, dose, delivery vehicle, etc of priobiotics.
Should You Take Probiotics?
The first problem is that health benefits conferred by probiotic bacteria depend on the specific species and strain of bacteria.
Secondly, probiotics are not INERT ingredients.
For example, you go to the store and buy a probiotic dietary supplement in a pill form. To start off with, there’s a good chance that the label information has inaccuracies in terms of the strain and species of bacteria along with the actual dose.
After that, the quantity of bacteria in your product will degrade over time as well. Maybe you brought the product because you’re going on a trip to Mexico and you want to prevent traveler’s diarrhea, but you purchased the wrong type of probiotic for that purpose to make matters worse.
Bottom line: Not all probitoics are indicated for the same health conditions.
Though not a complete overview, a recent study published by researchers from Queen’s University provides an overview of common types of probiotics that are currently available. Those included on this list have been relatively well-studied and researched for certain medical conditions such as antibiotic associated diarrhea or ulcerative colitis.
Overview of Common Probiotics:
VSL#3: A Mixture of Different Gram-positive Bacteria
The probiotic VSL#3 is a mixture of 8 different species of bacteria:
- Streptococcus salivarius subsp. thermophilus
- Lactobacillus casei
- Lactobacillus plantarum
- Lactobacillus acidophilus
- Lactobacillus delbrueckii subsp. bulgaricus
- Bifidobacteria longum
- Bifidobacteria infantis
- Bifidobacteria breve.
Health Conditions used for:
- chronic intestinal inflammation
- ulcerative colitis
E. Coli Nissle 1917: A Gram-negative Probiotic
- ulcerative colitis
Lactobacillus Rhamnosus GG: Gram-positive Probiotics
- acute diarrhea in pediatric population (most effective for rotavirus diarrhea)
- antibiotic associated diarrhea – strong level of evidence for preventing this.
Lactobacillus Reuteri: Gram-positive Probiotics
- acute diarrhea in children
Saccharomyces Boulardii: A Probiotic Yeast
- prevent antibiotic associated diarrhea
- treating recurrent Clostridium difficile-associated disease (common type of antibiotic associated diarrhea)
- ***important safety concerns including fungal infections in immunocompromised and elderly.
Source: Antiinflamm Antiallergy Agents Med Chem. 2009 Sep 1;8(3):260-269.