Probiotics: Replacing “Good” Bacteria

Antibiotics are prescribed in order to kill the “bad” bacteria associated with your illness or infection. Unfortunately, antibiotics are unable to distinguish between the “good” and “bad”what-might-happen-in-the-body-when-gut-health-is-compromised bacteria in your gut. This is why probiotics are recommended by your health care provider to prevent gastrointestinal complications such as diarrhea. However, there are many things beyond just antibiotics that can affect the regularity and efficiency of your GI tract, including disease states, food sensitivities, other medications, etc.  One of the easiest ways to regain control of your GI symptoms is to supplement your diet with “good” bacteria known as probiotics.

Probiotics are defined as “Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”1. These “good” bacteria can occur naturally in the diet through foods such as yogurt, kimchi, sauerkraut, and kefir or through probiotic supplements available in most pharmacies.  Probiotic supplements can contain many different types of “good” bacteria in approximately 10X the amount that you would find in dietary foods. Selecting a probiotic can be difficult and may even take multiple tries to find one that works for you. The most common probiotic available is Lactobacillus acidophilus; however there are many different probiotics species to choose from in each bacterial family (Lactobacilli, Enterococci, Bifidobacteria, and yeasts).2  The bacterial families work in different ways and in different parts of the GI tract which is why you often find combinations of these bacteria in probiotic supplements.

The Lactobacilli family works mainly in the upper GI tract (the mouth, esophagus and small intestine) producing lactic acid as it breaks down food producing an unfavorable environment for “bad” bacteria. Lactobacilli species have been found to improve digestion, absorption, and availability of nutrients in the upper GI tract. Bifidobacteria work in the lower GI tract and colon to break down complex carbohydrates and plant fibers for utilization by the body and have also been found to inhibit the adherence of “bad” bacteria, which may cause diarrhea, to the GI tract. Probiotic yeasts such as Saccharomyces boulardii have been found to enhance the growth of other probiotic bacteria under acidic conditions; however, yeasts have also been found as a cause of infection in immunocompromised patients. 2

Scientific studies within recent years have also discovered that probiotics can be useful in regulating a broad variety of disease states beyond the typical GI uses. A 2008 study conducted by Desbonett et al. shows evidence in support that Bifidobacteria possesses antidepressant properties via its ability to decrease “pro-inflammatory immune responses, and elevate the serotonergic precursor, tryptophan … However, these findings are preliminary and further investigation into the precise mechanisms involved, is warranted.”3 A 2015 study on probiotic effects on metabolic disorders shows that a number of probiotics such as VSL#3 can decrease weight gain, fat accumulation, cholesterol levels, and even increase insulin and glucose tolerance leading to benefits for those struggling with their weight or controlling their diabetes. 4,5

The benefits provided by probiotics continue to be discovered every day, with an increase in the number of studies seen over the past decade. Despite the benefits of probiotics, they should not be considered a “cure-all”. When given to the right patient at the right time, they can improve outcomes and help control disease states.  Talk with your doctor or one of our pharmacists for more information about how to add a probiotic to your medication regimen.


  1. FAO/WHO. (2001). Report of a Joint FAO/WHO Expert Consultation on Evaluation of Health, and Nutritional Properties of Probiotics in Food Including Powder Milk with Live Lactic Acid Bacteria (Córdoba: Food and Agriculture Organization of the United Nations, World Health Organization).
  2. Varankovich NV, Nickerson MT, Korber DR. Probiotic-based strategies for therapeutic and prophylactic use against multiple gastrointestinal diseases. Front Microbiol. 2015 Jul 14;6:685. doi: 10.3389/fmicb.2015.00685. eCollection 2015.
  3. Desbonnet, L., Garrett, L., Clarke, G., Bienenstock, J., and Dinan, T. G. (2008). The probiotic Bifidobacteria infantis: an assessment of potential antidepressant properties in the rat. J. Psychiatr. Res. 43, 164–174. doi: 10.1016/j.jpsychires.2008.03.009
  4. Le Barz M, Anhê FF, Varin TV, Desjardins Y, Levy E, Roy D, Urdaci MC, Marette A. Probiotics as Complementary Treatment for Metabolic Disorders. Diabetes Metab J. 2015 Aug;39(4):291-303. doi: 10.4093/dmj.2015.39.4.291
  5. Sunmin Park, Ji-Hyun Bae, Probiotics for weight loss: a systematic review and meta-analysis, Nutrition Research, Volume 35, Issue 7, July 2015, Pages 566-575, ISSN 0271-5317, http://dx.doi.org/10.1016/j.nutres.2015.05.008.(http://www.sciencedirect.com/science/article/pii/S0271531715001037)

Written by Melissa Buff, PharmD Candidate, Class of 2016, at the University of Maryland Eastern Shore School of Pharmacy