What to Look for in a Probiotic April 03 2018

Probiotics - you’ve probably heard of them - how they are good for you and you should take them and they’re in yogurt and sauerkraut and kombucha and who knows what else?  

But how much do you actually know about probiotics? Why do you need them? Do you know what to look for in a probiotic supplement? If you answered something along the lines of “not much” and “I don’t know” and “no,” then have no fear, Marilyn Farms is here! 

Let’s start our probiotic conversation with some fun basic biology facts. 

The average human has trillions of bacteria living in their body - in their intestines, on their skin, up their nose, wherever. In fact, bacteria in the human body outnumbers our cells 10:1 (1). That’s a lot of bacteria; 2-6 pounds of bacteria, to be precise. That’s more than your brain weighs! 

Okay, so if human beings are basically just large, 4-limbed, squishy containers for teeming cesspools of bacteria, why would we ever need to take a probiotic and put MORE bacteria into our bodies?! 

Well, consider this: the average human contains more than 10,000 species of bacteria, and in the ever-changing dynamic environment that is the human body, sometimes, those species get out of balance (1). Each species serves a specific role in the body. Some aid in digestion, some help us absorb nutrients, some protect against disease by fighting off pathogens like parasites and viruses, some help heal infection, others protect the gut from injury caused by ulcers, and some even synthesize vitamins. You need different bacteria to break down different food products, such as dairy, fat, proteins, and carbohydrates. When one species outcompetes another, you risk losing the essential metabolic function that the outcompeted bacteria provided for you. This can result in serious health consequences (1,2,3,4).  

There are many things that can contribute to an imbalanced gut fauna: diet, disease, environment, smoking and alcohol, use of antibiotics, and aging, to name a few (4). Unfortunately, some of those risk factors are hard to avoid, and this is where the importance of probiotics comes into play. By ensuring that you are getting the probiotics you need through daily supplementation, you can help counteract the loss of critical bacteria from your gut. 

 So, assuming you aren’t a sauerkraut-aholic, you might want to consider taking a probiotic supplement. Here are some things you should look for in a good probiotic, which we will expand on shortly: 

  • Variety of strains 
  • Type of strains 
  • Refrigerated 
  • Live, active cultures 

The actual importance of the number of bacteria in your probiotic (measured in colony forming units, CFUs) is something scientists are still debating about, so we’ll let them decide and get back to us on that. More important is the variety of strains and types of strains included. 

Here are some strains to look for in a probiotic, and what they can be used for (5): 

Lactobacillus species     

  1. acidophilus - digestion of dairy products, immune system support, protection against GI infection (6)
  2. plantarum- relief of abdominal pain and bloating (7) 
  3. rhamnosus- supports the immune system and particularly intestinal health (8) 
  4. brevis - important for tooth and gum health, protection against deterioration and inflammation of gums (9)
  5. fermentum- support of cardiovascular health, maintenance of healthy cholesterol levels (10) 

Bifidobacterium species 

  1. bifidum- support of immune system function, may help reduce severity and duration of minor illnesses (11) 
  2. longum- reduction of stress-induced gastrointestinal discomfort (12) 
  3. breve - anti-inflammatory, protection of gastrointestinal tract from disease and degeneration (13)
  4. adolescentis- may protect against allergic responses (14) 

A good probiotic will include several of lactobacillus and bifidobacterium strains, not just one. Look for a refrigerated probiotic, as this indicates the bacteria in it are live and active, as opposed to a shelf-stable product, which is less effective (but much more convenient for traveling). 

So, there you have it! If you are looking for a probiotic that meets these criteria, Marilyn Farms offers an excellent refrigerated probiotic from Custom Probiotics. But there are many good options out there, and now that you are informed, we’re sure you’ll find something you like! 


  1. National Institute of Health. NIH Human Microbiome Project defines normal bacterial makeup of the body. (2015, August 31). Retrieved March 17, 2017, from https://www.nih.gov/news-events/news-releases/nih-human-microbiome-project-defines-normal-bacterial-makeup-body  
  2. National Institute of Health, U.S. National Library of Medicine. Bifidobacteria. (n.d.). Retrieved March 17, 2017, from https://medlineplus.gov/druginfo/natural/891.html  
  3. National Institute of Health, U.S. National Library of Medicine.  Lactobacillus. (n.d.). Retrieved March 17, 2017, from https://medlineplus.gov/druginfo/natural/790.html 
  4. Zhang, Y., Li, S., Gan, R., Zhou, T., Xu, D., & Li, H. (2015). Impacts of Gut Bacteria on Human Health and Diseases. International Journal of Molecular Sciences,16(4), 7493-7519. doi:10.3390/ijms16047493 - access at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425030/  
  5. Collins, J., Thornton, G., & Sullivan, G. (1998). Selection of Probiotic Strains for Human Applications. International Dairy Journal,8(5-6), 487-490. doi:10.1016/s0958-6946(98)00073-9 
  6. Lactobacillus acidophilus. (n.d.). Retrieved March 21, 2017, from http://umm.edu/health/medical/altmed/supplement/lactobacillus-acidophilus  
  7. Ducrotté, P. (2012). Clinical trial: Lactobacillus plantarum 299v (DSM 9843) improves symptoms of irritable bowel syndrome. World Journal of Gastroenterology,18(30), 4012. doi:10.3748/wjg.v18.i30.4012 
  8. Oksaharju, A. (2011). Probiotic Lactobacillus rhamnosus downregulates FCER1 and HRH4 expression in human mast cells. World Journal of Gastroenterology,17(6), 750. doi:10.3748/wjg.v17.i6.750 
  9. Riccia, D. D., Bizzini, F., Perilli, M., Polimeni, A., Trinchieri, V., Amicosante, G., & Cifone, M. (2007). Anti-inflammatory effects of Lactobacillus brevis (CD2) on periodontal disease. Oral Diseases,13(4), 376-385. doi:10.1111/j.1601-0825.2006.01291.x 
  10. Kullisaar, T., Zilmer, K., Salum, T., Rehema, A., & Zilmer, M. (2016). The use of probiotic L. fermentum ME-3 containing Reg’Activ Cholesterol supplement for 4 weeks has a positive influence on blood lipoprotein profiles and inflammatory cytokines: an open-label preliminary study. Nutrition Journal,15(1). doi:10.1186/s12937-016-0213-6 
  11. Vrese, M. D., Winkler, P., Rautenberg, P., Harder, T., Noah, C., Laue, C., . . . Schrezenmeir, J. (2005). Effect of Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3, B. bifidum MF 20/5 on common cold episodes: A double blind, randomized, controlled trial. Clinical Nutrition,24(4), 481-491. doi:10.1016/j.clnu.2005.02.006 - access here: https://www.ncbi.nlm.nih.gov/pubmed/16054520  
  12. Messaoudi, M., Lalonde, R., Violle, N., Javelot, H., Desor, D., Nejdi, A., . . . Cazaubiel, J. (2010). Assessment of psychotropic-like properties of a probiotic formulation ( Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. British Journal of Nutrition,105(05), 755-764. doi:10.1017/s0007114510004319 
  13. Sagar, S., Morgan, M. E., Chen, S., Vos, A. P., Garssen, J., Bergenhenegouwen, J. V., . . . Folkerts, G. (2014). Bifidobacterium breve and Lactobacillus rhamnosus treatment is as effective as budesonide at reducing inflammation in a murine model for chronic asthma. Respiratory Research, 15(1), 46. doi:10.1186/1465-9921-15-46 
  14. Hevia, A., Milani, C., López, P., Donado, C. D., Cuervo, A., González, S., . . . Margolles, A. (2016). Allergic Patients with Long-Term Asthma Display Low Levels of Bifidobacterium adolescentisPlos One, 11(2). doi:10.1371/journal.pone.0147809  
Elanie Welch
Elanie graduated with a BA degree in Biology and Environmental Science from Coe College in Cedar Rapids, Iowa, and an MS degree in Occupational and Environmental Health from the University of Iowa. Elanie is currently working towards earning an MS degree in Human Nutrition from the University of Bridgeport. She enjoys all things biology, ecology, health, and science. Elanie is an amateur but avid chef, and she loves to find new ways to make healthy living the most accessible and exciting experience it can be.