What Are the Benefits of Probiotics?

What Are Probiotics?

Probiotics are living microorganisms that can be found in certain functional foods along with a variety of different dietary supplements.  When consumed in adequate amounts, some of them reach the intestine in an active state, where they’ve been shown to have a beneficial influence on the gastrointestinal tract.⁽¹⁾

More specifically, probiotics have been shown to improve the microbial balance in your gut.  Your digestive tract is actually filled with microorganisms like bacteria and archaea which collectively make up your gut microbiota (AKA your gut’s microbial community).    

While this might sound like a bad thing, some of these microorganisms actually aid in important metabolic activities, helping our bodies to break down dietary fibers, synthesize vitamins, and metabolize various biochemicals, amongst other things.⁽²⁾

When added into your diet, certain probiotics can contribute to the population of beneficial bacteria in the gut, which in turn, can lead to significant improvements in the overall health and function of the digestive system (we’ll talk about this in more detail in the following section.⁽³⁾

To date, most research with positive findings has tended to involved microorganisms from the Lactobacilli and Bifidobacterium families, with several different varieties being reported to have therapeutic effects in randomized clinical trials (RCTs).⁽⁴⁾⁽⁵⁾ While not exhaustive, the following list includes some of the most thoroughly investigated probiotics.  

Probiotics Benefits

When it comes to your gut health, research has, time and again, demonstrated that probiotics can improve the function of your gut in multiple ways. 

In studies involving both healthy individuals and those with inflammatory diseases of the gastrointestinal tract, probiotics have been shown to aid in everything from diarrhea prevention to the management of abdominal pain and intestinal inflammation.⁽⁶⁾

⫸Treat Diarrhea

To date, several probiotics, including L. acidophilus, L. rhamnosus GG, L. delbrueckii, L. fermentum, and Saccharomyces boulardii, have been shown to be effective at ameliorating diarrhea in humans, with numerous RCTs demonstrating their positive effects.⁽⁷⁾⁽⁸⁾

For instance, one study published in Alimentary Pharmacology and Therapeutics found that taking a probiotic supplement featuring L. rhamnosus twice a day for 5 days led to the amelioration of diarrhea in children experiencing infantile diarrhea.⁽⁹⁾

There is also a sizable body of evidence that certain probiotics can help to treat diarrhea in adults as well.  For example, one meta-analysis involving 25 different RCTs ultimately found that the probiotics L. rhamnosus and S. boulardii helped to significantly reduce the development of diarrhea in adults on antibiotics -- diarrhea is a side effect many people experience while taking antibiotics.⁽¹⁰⁾

Another meta-analysis published in the Journal of Travel Medicine and Infectious Disease found that the consumption of several different probiotics (of both the Lactobacilli of Bifidobacterium varieties) also helped reduce the occurrence of diarrhea amongst adult travelers -- diarrhea is a common side effect experienced by individuals traveling to foreign destinations.⁽¹¹⁾

⫸Reduce IBS Symptoms

There is also a considerable amount of evidence that probiotics can help to reduce the symptoms of Irritable bowel syndrome (IBS), which affects as many as 45 million Americans.

IBS is a commonly occurring gastrointestinal disorder characterized by things like flatulence as well as abdominal bloating and pain, amongst other things⁽¹²⁾

Several different probiotics, including  B. infantis, L. rhamnosus, B. breve, Propionibacterium freudenreichii, Bifidobacterium bifidum, and Escherichia coli have been shown to be effective at alleviating the symptoms of IBS.⁽¹³⁾

For example, one RCT published in Neurogastroenterology and Mortality found that 4 weeks of twice a day supplementation helped to significantly reduce flatulence in those who were given the probiotic L. rhamnosus.⁽¹⁴⁾

A 2011 study ultimately found that 4 weeks of consuming the probiotic Bifidobacterium bifidum significantly reduced abdominal pain, discomfort, and bloating in individuals diagnosed with IBS, leading to significant improvements in their overall quality of life.⁽¹⁵⁾

Another 2012 clinical trial came to a similar conclusion, finding that 12 weeks of supplementation helped to significantly reduce IBS symptoms amongst the 60 study participants who were administered a daily dose of the probiotic Escherichia coli.⁽¹⁶⁾

⫸Alleviate IBD

Several different probiotic species, including L. rhamnosus, L. casei, B. bifidum, S. boulardii, and E. coli have all been shown to be effective at reducing and even alleviating the symptoms of IBD in human trials -  especially in trials involving UC.^(18)(19)(20)

For example, one 12-month clinical trial involving over 300 participants ultimately found that a daily supplement of the probiotic E. coli was effective at maintaining remission in UC patients.⁽²¹⁾

Another RCT involving the probiotic L. rhamnosus came to a similar conclusion, finding that 12 months of supplementation was effective at preventing chronic intestinal inflammation, diarrhea, and abdominal pain in patients with UC.⁽²²⁾

⫸Improve Lactose Digestion

Research also suggests that some probiotics may help to significantly improve the symptoms of lactose intolerance, which is the most common kind of carbohydrate intolerance in the world.  Those who are lactose intolerant often experience symptoms such as bloating, diarrhea, abdominal distress, and flatulence.⁽²³⁾

More specifically, research findings from human-based trials suggest that the probiotics L.casei and B. breve have beneficial significant and beneficial effects on lactose digestion, helping to reduce the severity and occurrence of symptoms such as diarrhea, bloating, and abdominal pain.^(24)(25)

⫸Improve Lipid Metabolism

Several studies have demonstrated that probiotics may help to improve your lipid metabolism.  Microorganisms like L. bulgaricus, L. reuteri, L. acidophilus, and B. coagulans have all been shown to reduce serum cholesterol levels in human trials.⁽²⁶⁾

Other clinical research has demonstrated that the regular consumption of probiotics like B. longum and L. acidophilus can also lead to significant declines in triglycerides and improvements in HDL cholesterol.⁽²⁷⁾

There is also some evidence that prebiotics like xylooligosaccharides and fructooligosaccharides may help to decrease things like your total cholesterol and triglycerides as well.  

However, it’s important to point out that most of the positive findings come from animal studies.⁽²⁸⁾ With that being said, one 2010 trial involving humans did demonstrate a significant reduction in serum triglycerides in individuals with hypercholesterolemia.⁽²⁹⁾

⫸Boost Immune System and Fight Common Cold

Evidence from numerous clinical trials also suggests that probiotics may be helpful when it comes to fighting the common cold, which is an upper respiratory infection that regularly affects millions of Americans.    

Research findings suggest that several types of Lactobacillus and Bifidobacterium probiotics can help to bolster the immune system, which in turn can aid in the prevention of respiratory infections such as the common cold.⁽³⁰⁾

For example, One review involving 13 different RCTs found that individuals who regularly consume a probiotic supplement ultimately experienced a significantly lower rate of acute upper respiratory tract infection in comparison to those who were only given a placebo. And amongst those in the probiotic group who did still experience symptoms, they were ultimately less severe and of shorter duration in comparison to the placebo group.⁽³¹⁾

Another 2012 meta-analysis involving school children ultimately found that compared to a placebo group, children who regularly consumed the probiotics L. acidophilus and B. bifidum had a significantly lower risk of developing symptoms including fever, cough, and nasal congestion and were overall almost 20% less likely to come down with the common cold.⁽³²⁾

• References
  1. "Health Benefits of Probiotics: A Review" Kechagia, M., Basoulis, D., Konstantopoulou, Dimitriadi, D., Gyftopoulou, K., Skarmoutsoi, N., Fakiri, E.M. ISRM Nutrition. 2013.
  2. "Gut flora in health and disease" Gaurner, F., Malagelada, J-R. The Lancet. Feb. 2003.
  3. "Probiotics and immunity" Borchers, A.T., Selmi, C., Meyers, F.J., Keen, C.L., Gershwin, M.E. Journal of Gasteroenterology. Jan. 2009.
  4. "Probiotics, Prebiotics, and Synbiotics" de Vrese, M., Schrezenmeir, J. Food Biotechnology. May. 2008.
  5. "Health Benefits of Probiotics: A Review" Kechagia, M., Basoulis, D., Konstantopoulou, Dimitriadi, D., Gyftopoulou, K., Skarmoutsoi, N., Fakiri, E.M. ISRM Nutrition. 2013.
  6. "Probiotics, Prebiotics, and Synbiotics" de Vrese, M., Schrezenmeir, J. Food Biotechnology. May. 2008.
  7. "Meta-analysis of probiotics for the prevention of antibiotic associated diarrhea and the treatment of Clostridium difficile disease" McFarland, L.V. American Journal of Gastroenterology. Apr. 2006.
  8. "Probiotics: current trends in the treatment of diarrhoea" Narayan, S.S., Jalgaonkar, S., Kulkarni, V.N. Hong Kong Medical Journal. Jun. 2010.
  9. "Treatment of acute infectious diarrhoea in infants and children with a mixture of three Lactobacillus rhamnosus strains--a randomized, double-blind, placebo-controlled trial" Szymanski, H., Pejcz, J., Jawien, M., Chmielarczyk, A., Strus, M., Heczko, P.B. Alimentary Pharmacology and Therapeutics. Jan. 2006.
  10. "Meta-analysis of probiotics for the prevention of antibiotic associated diarrhea and the treatment of Clostridium difficile disease" McFarland, L.V. American Journal of Gastroenterology. Apr. 2006.
  11. "Meta-analysis of probiotics for the prevention of traveler's diarrhea" McFarland, L.V. Travel Medicine and Infectious Disease. Mar. 2007.
  12. "Probiotics, prebiotics and synbiotics- a review" Pandey, K.R., Naik, S.R. Vakil, B.V. Journal of Food Science and Technology. Jul. 2015.
  13. "The influence of Lactobacillus rhamnosus LC705 together with Propionibacterium freudenreichii ssp. shermanii JS on potentially carcinogenic bacterial activity in human colon" Hatakka, K., Holma, R., El-Nezami, H., Suomalainen, T., Kuisma, M., Saxelin, M., Poussa, T., Mykkanen, H., Korpela, R. International Journal of Food Microbiology. Sep. 2008.
  14. "A randomized controlled trial of a probiotic combination VSL# 3 and placebo in irritable bowel syndrome with bloating" Kim, H.J., Vazquez-Roque, M.I, Camilleri, M., Stephens, D., Burton, D.D., Baxter, K., Thomforde, G., Zinsmeister, A.R. Nerogastroenerology and Motility. Oct. 2005.
  15. "Randomised clinical trial: Bifidobacterium bifidum MIMBb75 significantly alleviates irritable bowel syndrome and improves quality of life--a double-blind, placebo-controlled study" Guglielmetti, S., Mora, D., Gschwender, M., Popp, K. Alimentary Pharmacology and Therapeutics. May. 2011.
  16. "A double-blind placebo-controlled trial to study therapeutic effects of probiotic Escherichia coli Nissle 1917 in subgroups of patients with irritable bowel syndrome" Kruis, W., Chrubaski, S., Boehm, S., Stange, C., Schulze, J. International Journal of Colorectal Disease. Dec. 2011.
  17. "Probiotics, prebiotics and synbiotics- a review" Pandey, K.R., Naik, S.R. Vakil, B.V. Journal of Food Science and Technology. Jul. 2015.
  18. "Efficacy and safety of the probiotic Saccharomyces boulardii for the prevention and therapy of gastrointestinal disorders" Kelesidis, T., Pothoulakis, C. Therapeutic Adcvances in Gastroenterology. Mar. 2012.
  19. "Probiotics in the management of inflammatory bowel disease: a systematic review of intervention studies in adult patients" Jonkers, D., Penders, J., Masclee, A., Pierik, M. Drugs. Apr. 2012.
  20. "Probiotics and IBD" De Greef, E., Vandenplas, Y., Hauser, B., Devreker, T., Veereman-Wauters, G. Acta Gastro-enterologica Belgica. Feb. 2013.
  21. "Maintaining remission of ulcerative colitis with the probiotic Escherichia coli Nissle 1917 is as effective as with standard mesalazine" Kruis, W., Fric, P., Pokrotnieks, J., Lukas, M., Fixa, B., Kascak, M., Kamm, M.A., Weismueller, J., Beglinger, C., Stolte, M., Wolff, C., Schulze. Gut. Nov. 2004.
  22. "Efficacy of Lactobacillus GG in maintaining remission of ulcerative colitis" Zocco, M.A., dal Verme, L.Z., Cremonimi, F., Piscaglia, A.C., Nista, E.C., Candelli, M., Novi, M., RIgante, D., Cazzato, I.A., Ojetti, V., Armuzzi, A., Gasbarrini, G., Gasbarrini, A. Jun. 2006.
  23. "Probiotics, prebiotics and synbiotics- a review" Pandey, K.R., Naik, S.R. Vakil, B.V. Journal of Food Science and Technology. Jul. 2015.
  24. "Guidance for Substantiating the Evidence for Beneficial Effects of Probiotics: Impact of Probiotics on Digestive System Metabolism" Rabot, S., Rafter, J., Rijkers, G.T., Watzl, B., Antoine, L-M. The Journal of Nutrition. Mar. 2010.
  25. "Comparative effects of exogenous lactase (β-galactosidase) preparations onin vivo lactose digestion" Lin, M-Y., Dipalma, J.A., Martini, M.C., Gross, C.J., Harlander, S.K., Nov. 1993.
  26. "Probiotics and Lactose Intolerance" Sudha, M.R., Chauhan, P., Dixit, K., Babu, S., Jamil, K. Biology and Medicine. 2009.
  27. "Probiotics, prebiotics and synbiotics- a review" Pandey, K.R., Naik, S.R. Vakil, B.V. Journal of Food Science and Technology. Jul. 2015.
  28. "Xylooligosaccharides and fructooligosaccharides affect the intestinal microbiota and precancerous colonic lesion development in rats" Hsu, C-K., LIao, J-W., Chung, Y-C., Hsieh, C-P., Chan, Y-C. Journal of Nutrion. Jun. 2004.
  29. "Probiotics, prebiotics and synbiotics- a review" Pandey, K.R., Naik, S.R. Vakil, B.V. Journal of Food Science and Technology. Jul. 2015.
  30. "Probiotics for preventing acute upper respiratory tract infections" Hao, Q., Dong, B.R., Wu, T. Cochrane Systematic Reviews. Feb. 2015.
  31. "Probiotics for preventing acute upper respiratory tract infections" Hao, Q., Dong, B.R., Wu, T. Cochrane Systematic Reviews. Feb. 2015.
  32. "Randomized controlled trial of probiotics to reduce common cold in schoolchildren"Rerksuppaphol, S., Rerksuppaphol, L. Pediatrics International. Apr. 2012.