What are Probiotics?

The World Health Organization defines probiotics as live organisms (bacteria or yeast) which, when administered in adequate amounts, confer a health benefit. The public is exposed to pervasive claims for probiotics, by a multi-billion dollar industry, without clear guidance or convincing raw data. Ads promise that probiotics will fortify digestion, strengthen immunity, curb colds and flu, promote weight loss and even protect against periodontal disease- but what are we to believe and where is the evidence?

The Gastrointestinal System

The GI tract is a highly evolved system designed to allow nutrient digestion, absorption and waste disposal. Over 10 trillion microbes (comprised of 500 species) live in the GI tract and can weigh up to three pounds. In fact, bacterial cells outnumber human cells by a ratio of 10:1. Gut bacteria help to maintain gastrointestinal health and their composition is influenced by factors such as age, diet and disease.

The gut immune system differentiates between bacteria to be tolerated and bacteria requiring an immune response. An inappropriate immune response to certain bacteria may be a significant component in several diseases, such as Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD). Probiotics are thought to rebalance the microflora in the colon and may possibly modify the gut’s immune response.

When to Take Probiotics

Probiotics are used in a variety of GI disorders such as IBS and IBD. IBS is a disorder of unknown cause, but contributing factors can include psychological and emotional stress or an ‘oversensitive’ GI tract. Some studies have shown that the composition of bacteria in patients with IBS is different than in healthy people. Probiotics may help decrease the symptoms of gas and bloating by restoring normal bacterial balance. IBD (Ulcerative Colitis and Crohn’s) is thought to be caused by an excessive immune response to antigens in the gut of those who are genetically predisposed to it. At this point, the role of probiotics in their treatment is still ill-defined. Some studies have shown that probiotics reduced the risk of antibiotic associated diarrhea, yet other studies have found that it works no better than a placebo. Clearly, more research is needed.

About Probiotics

Probiotics come in a range of formulations including capsules, powders, yogurts and fermented milks or fruit drinks. The most commonly used probiotics are lactobacillus and bifidobacteria as well as certain yeasts. At this time, probiotics are not regulated by the FDA and ad claims that probiotics “support good digestive health” are basically unproven.

Probiotics are generally thought to be safe when taken by healthy individuals but there are concerns about its use with infants and patients with compromised immune systems. There are also side effects to be considered such as overstimulation of the immune system, fatigue, pruritis (itching) and diarrhea.

The Bottom Line

There is increasing interest in the relationship between gut bacteria in human health and disease. Possible future indications for the use of probiotics for mood disorder, obesity, autism and dementia are being evaluated.

There are many questions regarding the usefulness of probiotics in GI disorders. While there is some evidence to support a role in some conditions, at this time probiotics should be considered as a supplement to conventional therapy. There is a strong need for targeted studies to test specific strains for particular conditions and to ascertain appropriate doses and administration.

Check with your gastroenterologist to see if probiotics would be beneficial and safe for you.