What is a probiotic?

These days, the word ‘probiotic’ seems to be everywhere. But, what does it mean? Probiotic means ‘for life,’ but is used to refer to the ‘good bugs’ (bacteria and yeast) that live in our intestines.

“I have bacteria in my intestines?”

Yes, but not all bugs are bad! Normal gut flora perform a variety of functions:

  • Ferment soluble dietary fiber and produce substances that keep the intestines and the whole body healthy1
  • Decrease diarrhea that can occur during gastrointestinal infections, and decrease overall intestinal inflammation2
  • Decrease inflammation in the rest of the body by calming the immune system, and increasing the production of anti-inflammatory signals2
  • Shift the balance of the immune system, mediating allergic/inflammatory response3
  • Play a role in the production of certain vitamins including folic acid, biotin, vitamin K, and other B vitamins.5

Why don’t I have enough of the good bugs?

The good bugs can be killed off by antibiotic use, or crowded out by overpopulation of the bad bugs. Antibiotics can be extremely helpful when we need to take them for a bacterial infection, but they don’t discriminate about which bugs they kill in the body, making your healthy gut flora collateral damage. Unfortunately, antibiotics as medical treatment are not the only source of exposure. Antibiotics given to farm animals can be transmitted to humans when we eat the meat or milk of those animals, reeking havoc with our intestinal flora.

Overpopulation of the bad bugs is another way that our gut flora is affected. Even if we seldom take antibiotics and only eat organic meats and dairy products, diets high in sugar and refined carbohydrates promote the growth and overpopulation of the bad bugs which crowd out the healthy gut flora. In addition, medications given for acid reflux and indigestion that work to buffer the stomach acid and relieve discomfort change the gut environment and make it easier for the bad bugs to survive the stomach and travel down to the intestine where they grow and proliferate.

Can supplementing with probiotics improve my health?

Recently, supplementing with probiotics has become very common in capsules, powders and even in yogurt. The health benefits claimed by the supplement companies are many and varied, but is there science to back this up? The answer is yes, but there are two questions that need to be addressed even before we can know if supplementing honestly does any good;

Are you supplementing with the right species to help your particular health problem?, and

Are you supplementing with enough cultures to do any good?

In order to do any good, a probiotic must be from a human source, be a safe species (won’t cause illness), be resistant to digestion in the stomach and intestines, and it has to be able to stick to and grow on the intestinal walls. If it’s not the right bug, one that won’t die, and one that is able to stay in the intestines, then it’s not going to provide any health benefits. If the probiotic is able to do all those things, then it also has to:

  1. produce substances that help inhibit the growth of the ‘bad bugs,’
  2. help control the immune system in a good way, and also
  3. influence the breakdown and use of the foods we eat.2

What kinds of conditions can supplementing with probiotics possibly help?

The conditions that have been studied demonstrating potential benefit from probiotic therapy include:

·         Constipation1

·         Acute infectious diarrhea1,2

·         Antibiotic-associated diarrhea (Saccharomyces boulardii)1,2

·         Neonatal necrotizing enterocolitis (Bifidobacteria spp.)2

·         Lactase deficiency2

·         IBS (Bifidobacterium infantis1)

·         Ulcerative colitis (Lactobacillus GG1,2, Saccharomyces boulardii1, VSL#3:  high concentration mixture of B breve, Bifidobacterium longum, B infantis, L acidophilus, L plantarum, L casei, Lactobacillus bulgaricus, and Streptococcus thermophilus1)

·         Celiac disease2

·         Food hypersensitivity (Bifidobacteria spp.)2

·         H.Pylori infection2

·         Pouchitis (VSL#3)1

Is there any risk associated with using probiotics?

The potential risks that have been reported are generally very minor including temporary mild gastrointestinal (GI) complaints such as diarrhea, increased flatulence, and changes in bowel habits.2 Rare, anecdotal risks reported include spread of bacteria in the blood in children treated with probiotics, primarily in those with poor immune function or underlying heart anomalies. Unhealthy spread was reported in several cases of adults in ICU care treated with the strain sacchacromyces cerevisia, and questions have been raised as to the safety of using probiotics in newborns with poor immune function based on the observation of one study using mice.2

Despite these potential risks, probiotics are generally quite safe. More and more research is demonstrating that using probiotics can be an effective way to help treat a variety of GI problems, and serve an important preventive role in immune function and general health.2

How do I know if a probiotic is of good quality?

These are some rough guidelines for selecting a safe and effective probiotic:2

·  Live strains seem to be more effective; choose a probiotic that is refrigerated. If not, contact the company and ask for information regarding strain viability at room temperature.

·  Choose a probiotic with a variety of strains, not just one or two. If you’re hoping to address a particular health condition, make sure the strains indicated for your condition are included in the product.

·  The number of cultures is important: several billion to tens of billions per day depending on your health goals (preventive vs. therapeutic application)

Should everyone supplement with probiotics?

While we can’t yet say that everyone should supplement with probiotics, so far the research shows that the potential benefits vastly outweigh the risks in most people. As information continues to accumulate, more specific recommendations will be available including when to apply which strains, how many strains are necessary for treatment vs. maintenance goals, which combination of strains works the best, how and when to use prebiotics, etc. Until then, for most people the use of probiotics seems to be a reasonable and safe option for addressing some health concerns and possibly for good health maintenance, but working under the guidance of a knowledgeable health professional is still the best course of action.


 1     Park, J., & Flock, M. H. (2007). Prebiotics, probiotics, and dietary fiber in gastrointestinal disease. Gastroenterology Clinics of North America. 36, 47-63.

 2     Kliegman, R. M., Behrman, R. E., Jenson, H. B., Stanton, B. F., (2007). Nelson textbook of pediatrics (18th ed.). Saunders; Philadelphia, PA.

 3     Kidd, P. (2002). Th1/Th2 balance: The hypothesis, its limitations, and implications for health and disease. Alternative Medicine Reviews, 8,3, 223-246.

 4     Percival, M. (1997). Choosing a probiotic supplement. Clinical nutrition insights, 6, 1, 1-4.

 5     Haddad, P. S., Azar, G. A., Groom, S. & Boivin, M. (2005). Natural health productions, modulation of immune function and prevention of chronic diseases. eCAM, 2,4, 513-520.

Ester Roy, ND is a Holistic Health Coach and Contributing Author for Monaco. Dr. Roy is a licensed Natural Medicine Doctor and passionate about helping clients achieve their health and wellness goals.  She also holds a BA in Psychology and a Master’s in Exercise Science. Dr. Roy has an ardent heart for health education and created her practice with an emphasis on cardiovascular disease, digestive problems, anxiety, metabolic disturbance, weight management, nutrition, wellness and preventive care .