The Surprising Benefits of Probiotics – What You Didn’t Know

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From encouraging and protecting healthy digestion & elimination to reducing inflammation and supporting the immune system, probiotics play many essential roles in our overall health.

With the growing interest in healthy living and integrative medicine, the use of beneficial bacteria has become a popular topic. And as research continues to reveal the multiple health benefits of probiotics, many healthcare professionals have begun recommending them for their patients.

What Are Probiotics? 

The word probiotics literally means “for life” (from the Latin pro, meaning “for” and the Greek biota, meaning “life”).

The official definition of probiotics, adopted in 2002 by the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO), is “Live microorganisms which, when administered in adequate amount, confer a health benefit on the host.” In simpler terms, probiotics are “good” bacteria.

The Bacterial Balancing Act

Before we can discuss the benefits of probiotics, it’s important to understand how bacteria work in our bodies. Here are some interesting facts about bacteria:

• Bacteria can be found pretty much everywhere.

• In humans, these microscopic organisms live on the skin and in mucosa.

• An estimated 500 to 1,000 different species of bacteria inhabit the gut and a similar number live on the skin.

• The bacterial population in humans is so large that bacterial cells outnumber human cells by 10 to 1.

• The vast majority of bacteria in humans can be found in the large intestine.

• Approximately 100 trillion of these microorganisms live in a normal, healthy bowel.

Over the years, bacteria have gotten a lot of negative press. Most people associate bacteria with the four Ds: dirt, disease, death and decay. While it’s true that some bacteria do cause diseases and even death, the majority of bacteria are actually beneficial to your health.

In reality, only about 10% of bacteria are “bad.” The other 90% are “good” bacteria that aid in food digestion, regulate proper immune function, and defend against disease-causing pathogens. 

In order to keep a body healthy, bacteria must maintain a delicate balancing act.  It’s the biological version of the classic struggle of good vs. evil. As long as the good bacteria predominate, they can effectively fight off the “evil” or bad bacteria.

However, when the ecology of the gastrointestinal tract becomes disrupted, the good bacteria can no longer flourish in needed numbers and proper balances. It is then that harmful toxin-producing bacteria begin to take over.

Antibiotics: The Good, the Bad and the Ugly

When it comes to disrupting the body’s bacterial balance, one of the biggest culprits is antibiotics. The purpose of antibiotics is to destroy disease-causing bacteria. The problem is that antibiotics can’t distinguish good bacteria from bad, so they kill both.

Antibiotics are what you might call a necessary evil. To be sure, they are an important tool for fighting serious disease and can save lives. But they can also cause troublesome side effects like antibiotic-associated diarrhea (AAD). And if the good bacteria are not replenished quickly, antibiotics can leave you open to other illnesses.

An article in The Internet Journal of Nutrition and Wellness gives a good description of the relationship between probiotics and antibiotics:

A person taking antibiotics is equivalent to pouring bleach into a fish tank to kill an overgrowth of algae. The bleach not only kills the algae but everything else that is present in that environment…. It is necessary for people taking antibiotics to alternate with probiotics, because antibiotics kill beneficial bacteria along with the bacteria causing the illness.”(1)

Even if you don’t often take antibiotics, you are still likely to be getting them through your food and water. Giving antiobiotics to food-animals like cows, swine, chickens and fish – so they will gain more weight faster as well as to prevent infection – is a common practice. Scientists are also discovering significant levels of antibiotics in our water supplies from a variety of sources.

So your body is probably getting a lot more antibiotics than you realize.

To further support the use of probiotics when taking an antibiotic, a meta-analysis study of probiotic therapy to reduce the incidence of antibiotic-associated diarrhea was presented at the American College of Gastroenterology’s (ACG) 76th Annual Scientific meeting in October 2011. Twenty-two studies were analyzed, which included a total of 3,096 patients. The treatment periods ranged from five days to three weeks, with the average being 1.5 weeks. According to lead authors Rabin Rahmani, MD and Steven Shamah, MD:

Overall in 22 studies, probiotic prophylaxis significantly reduced the odds ratio of developing AAD by approximately 60%. This analysis clearly demonstrates that probiotics offer protective benefit in the prevention of these diseases.”

These findings suggest that all patients who are at high-risk for these infections demonstrated by recent antibiotic usage, old age, recent hospitalization, low albumin, and immunosuppression should be considered for probiotic therapy.”(2)

History of Probiotics

The concept behind probiotics was first introduced in the early 20th century, when Nobel laureate Elie Metchnikoff, known as the “father of probiotics,” proposed in The Prolongation of Life: Optimistic Studies that ingesting microorganisms could have substantial health benefits for humans. In his milestone book, Dr. Metchnikoff documented what he believed to be a direct link between human longevity and the necessity of maintaining a healthy balance of beneficial microorganisms within the body.

Although researchers continued to carry on Dr. Metchnikoff’s work, it moved along slowly until the tail end of the 20th century. That’s when we began to see a dramatic increase in probiotic research. A 2003 article in the journal Clinical Microbiology Reviews stated: “A Medline search of the term probiotics illustrates the significant increase in research undertaken in this area during the past 5 years: Over 1,000 publications cited, compared to 85 for the previous 25 years.”(3)

The U.S. has been slow to jump on the probiotics bandwagon.

Europeans consume a lot of probiotics because they traditionally eat foods like yogurt and sauerkraut that are fermented with bacteria. Likewise, Southeast Asians eat a lot of foods high in probiotics such as kimchi and miso soup. And beverages laced with probiotics have become big business in Japan. Despite getting a slow start, though, the U.S. consumer market for probiotics is now growing rapidly.

Additional Benefits of Probiotics

Western medicine has a reputation of being reticent when it comes to recognizing the benefits of supplements and other natural therapies, but in the case of probiotics, many highly respected medical authorities are acknowledging their positive effects.

According to the Mayo Clinic, “Although more research is needed, there’s encouraging evidence that probiotics may help:

• Treat diarrhea, especially following treatment with certain antibiotics

• Prevent and treat vaginal yeast infections and urinary tract infections

• Treat irritable bowel syndrome (IBS)

• Reduce bladder cancer recurrence

• Speed treatment of certain intestinal infections

• Prevent and treat eczema in children

• Prevent or reduce the severity of colds and flu”(4)

The Harvard Medical School Family Health Guide states, “Since the mid-1990s, clinical studies have established that probiotic therapy can help treat several gastrointestinal ills, delay the development of allergies in children, and treat and prevent vaginal and urinary infections in women.”(5)

The ME/CFS – Probiotic Connection

A highlight of the American College of Gastroenterology’s 2011 Scientific Meeting was a report on the significant benefits of the probiotic strain Bifidobacterium infantis 35624 “as an anti-inflammatory agent” in a trial including patients with chronic fatigue syndrome (ME/CFS), psoriasis, and ulcerative colitis.

B infantis, a primary inhabitant of the digestive tract of newborn infants, is considered essential for good health in both infants and adults.

The double-blind, placebo controlled study included healthy volunteers, and 27 patients with psoriasis, 24 with ulcerative colitis, and 50 with chronic fatigue syndrome. The results of the eight-week study indicated that:

• Plasma levels of the anti-inflammatory cytokine, IL-10, were significantly increased in healthy volunteers and psoriasis patients, but not in placebo treated patients.

• Plasma levels of the pro-inflammatory cytokines TNF-alpha and IL-6 were significantly reduced in all patient groups that received B. infantis.

• C-reactive protein (CRP) levels were also significantly reduced in psoriasis, ulcerative colitis and chronic fatigue patients at the end of treatment with B infantis compared to placebo treated patients. [Elevated CRP in the blood is a key indicator of acute or chronic inflammation associated with a wide range of acute and chronic inflammatory conditions.]

“The human immunological response to B infantis further supports the hypothesis that manipulation of the microbiota with specific therapeutic microbes can have a significant effect on host inflammatory processes,” says Eamonn M M Quigley, MD, FACG, who presented the findings.(6)

Lyme Disease and Probiotics

Because Lyme disease is primarily treated with antibiotics, probiotics are recommended by most Lyme experts. The University of Maryland Medical Center says, “Probiotics, or “friendly” bacteria, help maintain intestinal health. If you take antibiotics to treat Lyme disease, the antibiotics will kill the “good” bacteria along with the bad. That can cause diarrhea or yeast infections. Taking probiotics may reduce these side effects.”

Monostrain vs. Multispecies Probiotics

Many studies looking at the effect of probiotics on various conditions have reported positive results. While some have failed to find significant benefits, a number of scientists now theorize that this is because most of the past probiotic research had focused on studying one probiotic strain at a time. Since the human gut contains several hundred different microbe species, they feel it may be more beneficial for the body to consume multiple probiotic strains and species.

Emerging research seems to be backing up their theory.  A 2004 literature review found that:

• Multispecies probiotics were superior to both monostrain and multistrain probiotics for treating antibiotic-associated diarrhea in children.

• Growth performance and particularly mortality in chickens could be improved with multistrain probiotics.

• Mice were better protected against S. Typhimurium (a Salmonella food poisoning, most often from raw eggs) infection with a multistrain probiotic.

• A multispecies probiotic provided the best clearance of E. coli O157:H7 from lambs.

• Rats challenged with S. Enteritidis (another commonly infective Salmonella species) showed best post-challenge weight gains when treated with a multispecies probiotic.(7)

Irritable Bowel Syndrome

A 2008 study investigated the effect of a multistrain probiotic supplement on symptoms of IBS. The results showed a significantly greater improvement in the Symptom Severity Score of IBS and in scores for quality of life, days with pain, and satisfaction with bowel habit over the 8-week intervention period in the volunteers receiving the probiotic preparation.(8)

The Future of Probiotics

The National Center for Complementary and Alternative Medicine (NCCAM) has designated probiotics as a high-priority topic for upcoming clinical research projects. Recent and future studies include:

• Prevention and treatment of diarrhea in infants.

• Potential benefits for adults and children with irritable bowel syndrome and for people with minimal hepatic encephalopathy (a complication of liver disease).

• Treatment of an antibiotic-resistant type of bacteria.

• Yogurt beverages as a way of giving high doses of probiotics to young children.

• Gastrointestinal disorders in infants and children, including necrotizing enterocolitis, colic, and irritable bowel syndrome.

• Treating and preventing antibiotic-induced diarrhea.

• Enhancing the effects of flu vaccine.

NCCAM is also supporting laboratory studies that explore possible mechanisms of action for probiotics, providing a foundation for clinical research. For example, recent studies have found evidence that:

• A strain of Lactobacillus reuteri might slow the growth of certain tumors.

Lactobacillus acidophilus (a widely used and studied probiotic) might enhance the effects of a vaccine against rotavirus infection – the most common cause of infectious diarrhea in infants and children worldwide.


Probiotics provide the beneficial bacteria our bodies need to maintain healthy digestion and to counteract some of the side effects of antibiotics. There is also growing evidence that they may provide significant benefits for a number of other health issues, such as helping to reduce inflammation and enhancing proper immune system function.


1.  Biradar SS, Bahagvati ST, Shegunshi B. “Probiotics And Antibiotics: A Brief Overview.” The Internet Journal of Nutrition and Wellness. 2005 Volume 2 Number 1.

2.  American College of Gastroenterology news release, Oct 31, 2011; ACG 2011 Scientific Meeting Poster P650 abstract.

3.  Gregor R, et al. “Potential Uses of Probiotics in Clinical Practice.” Clin Microbiol Rev. 2003 October; 16(4): 658–672.

4.  Zeratsky, K. (2011, September 15). “Is it important to include probiotics and prebiotics in a healthy diet?”  Retrieved from

5.  Komaroff, A. (2005, September). “Health benefits of taking probiotics.” The Harvard Medical School Family Health Guide, Retrieved from

6.  American College of Gastroenterology news release, Oct 31, 2011; ACG 2011 Scientific Meeting Poster P283 abstract.

7.  Timmerman HM, et al. (November 2004). “Monostrain, multistrain and multispecies probiotics – A comparison of functionality and efficacy.” Int. J. Food Microbiol. 96 (3): 219–33.

8.  Williams E, Stimpson J, Wang D et al. (September 2008). Full text: “Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study”. Aliment. Pharmacol. Ther. 29 (1): 97–103.


* Supplement research writer Karen Lee Richards is the Lead Expert specializing in Fibromyalgia and ME/CFS, for HealthCentral’s ChronicPainConnection. Karen is co-founder of the National Fibromyalgia Association and was Executive Editor of Fibromyalgia AWARE magazine for four years.

Note: This information has not been evaluated by the FDA. It is general information and is not intended to diagnose, prevent, treat or cure any illness, condition or disease. It is very important that you make no change in your healthcare plan or health support regimen without researching and discussing it in collaboration with your professional healthcare team.

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One thought on “The Surprising Benefits of Probiotics – What You Didn’t Know”

  1. TheFastDoctor says:

    Interesting and very valid article.

    Of course it came as a bit of a surprise when the medical community eventually agreed on the man function of the human appendix: Sitting right at the junction of the small and large intestine, the appendix acts a bit like “Noah’s Ark”: It harbours up to 300 different species of bacteria (probiotics) and “seeds” them unto the partially digested intestinal content as it passes into the colon. These bacteria then produce a large number of midro-nutrients in a symbiotic relationship with the body.

    One reason why we should eat more raw food is that the less digestible parts will reach the colon where our innate probiotics will flourish. And of course, if a probiotic is succesful, one needs be exposed only once, whereafter they will multiply in the colon and establish a small “core” of replacements in the appendix.. a bit like a seed store.

    I use and prescribe probiotics whenever there is diarrhea or when antibiotics is used, until about one day after resolution of the symptoms. Thereafter they will multiply themselves, even in people who have lost their appendixes.

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