By Lawrence J. Hoberman, MD

Gastrointestinal disorders represent a common cause for physician office visits, with an estimated 2.7 million visits due to a diagnosis of Irritable Bowel Syndrome. It is estimated that only 10 percent to 30 percent of affected patients seek treatment. The cause of IBS is considered to be multifactorial, and treatment options are quite diverse. This article describes how probiotics can be a useful therapy for a variety of GI disorders, including IBS.

Before discussing some of the clinical benefits of probiotics, I would like to share some information about our intestinal bacteria. We have 100 million bacteria in our intestinal tract. Studies have found that the intestinal micro flora consists of 500 to 1,000 different species. Generally, for each individual, 99 percent of the bacteria are composed of 30 to 40 different species. Our permanent intestinal flora is established by age 2 and will depend on our exposure to the environment. The bacterial population will be different in children growing up on farms or underdeveloped countries compared to children living in modern cities.

Some of the effects of the intestinal flora on the human host are:

  1. The bacteria interact with the intestinal immune cells and can modulate immune responses. The bacteria can stimulate cytokine production resulting in an increase or a decrease in the inflammatory reaction.
  2. The bacteria ferment resistant starches in our diet which results in the production of short chain fatty acids like butyric acid. The colonocytes are dependent on butyrate as their energy source. In addition, when butyrate is absorbed, it acts as a solvent drag and increases water and electrolyte absorption.
  3. The bacteria have an effect on the metabolism of drugs, digestion of carbohydrates and produce vitamin B, K and folate.

Unfortunately, when we eat unhealthily, travel, experience stress or take medications such as antibiotics, we can disrupt the healthy intestinal bacterial balance. Harmful organisms can start to multiply which can then result in a variety of intestinal disorders. Probiotics can help to re-establish a healthy intestinal balance of the bacteria.

Probiotics are mainly derived from healthy intestinal flora. These bacteria are selected if they can be shown to:

  1. Survive exposure to gastric acid, bile and digestive enzymes;
  2. Adhere to colon lining cells and proliferate;
  3. Be free of any toxicity and are safe when ingested.

Probiotics have been shown in randomized double-blind studies and meta-analysis reviews to:

  1. Ease the symptoms of IBS by normalizing stool habits and lessen flatulence;
  2. Lessen the risk of traveler’s diarrhea;
  3. Lessen the risk of antibiotic-related diarrhea;
  4. Lessen the risk of developing Clostridia difficle colitis;
  5. Lessen vaginal yeast infections and recurrent female urinary tract infections;
  6. Lessen the risk and duration of childhood viral gastroenteritis;
  7. Improve infantile colic; and
  8. Lessen atopic disease in childhood.

As more good scientific studies have been published on the mechanisms of action and the clinical benefits of probiotics, mainstream medicine has become more comfortable recommending probiotics to patients.

The problem is that there are a number of probiotic preparations on the market. The majority consist of the Bifidobacteria and Lactobacillus species. There is also a yeast probiotic that contains saccharomyces boulardii.

Probiotics can be delivered in pills, capsules, powder, liquid and added to foods such as yogurt.

Studies in general have found that multispecies/multistrain products are more effective. In addition, the amount of bacteria in a serving size is very important.

The general recommendation is to use a probiotic that contains a serving size of 8 billion to 10 billion colony forming units (cfu) or more to ensure clinical benefit. The probiotic should also contain multiple strains of Lactobacillus and Bifidobacteria, like L. acidophilis L. lactic, B. bifidum and B. breve.

Food supplements such as yogurt contain one probiotic, and it is difficult to know how many cfu’s of the bacteria are in a yogurt serving.

The bottom line is to consider recommending a probiotic supplement:

  1. When prescribing broad spectrum antibiotics…advise the patient to take the probiotic two hours before or after the antibiotic dose;
  2. For patients with ongoing symptoms of IBS;
  3. When patients are traveling to third-world countries, especially if they are on acid suppressive therapy which increases the risk of developing traveler’s diarrhea;
  4. For children with infantile colic;
  5. For infants with a strong family history of atopic disease;
  6. For children receiving antibiotics like Augmenten for otitis media.

Lawrence J. Hoberman, MD, is board certified in internal medicine and gastroenterology. For more information, visit

PDF Version