Can Too Many Probiotics Be Harmful?

The human body, particularly the intestines, naturally contains bacteria that are beneficial to health. Probiotics are designed to boost the levels of these bacteria. Probiotics are generally safe for human consumption, but there are some potential risks with using probiotics, particularly if you consume them in very high quantities.

Probiotic Identification

Probiotics is a blanket term used to describe any sort of microorganism that benefits human health when consumed, the National Center for Complementary and Alternative Medicine explains. Most probiotics are bacteria, such as Bifidobacterium or Lactobacillus acidophilus that resemble those normally found in the digestive tract. Some yeasts, such as Saccharomyces cerevisiae, are also considered probiotics. Some foods, such as tempeh, certain dairy products and miso contain probiotic bacteria, but these bacteria also are available in freeze-dried powders, capsules and granules.

Benefits

Taking probiotic bacteria replenishes and boosts the levels of "good" bacteria in your gut. The natural bacteria in your intestines help you digest food, stimulate your immune system and help crowd out potentially infectious bacteria. Probiotic supplements are particularly useful after taking a course of antibiotics, as the antibiotics wipe out the healthy bacteria in your digestive tract, making you susceptible to diarrhea and infection, MayoClinic.com explains.

Infection Risk

Although the bacteria in probiotic supplements are designed to not be infectious, there are cases of these bacteria causing dangerous infections, a 2003 article in "Clinical Infectious Diseases" notes. If bacteria overgrow in the intestines, they can enter the blood stream where they can either infect the heart, resulting in endocarditis; or they cam multiply in the blood, causing a condition known as bacteremia. These cases are rare, however, and usually only occur in patients who are already severely ill.

Other Risks

Other risks of taking too many probiotics are identified in a 2006 article in the "American Journal of Clinical Nutrition." Because of their role in metabolism and digestion, excessive use of probiotics may interfere with normal metabolism in the body. Large amounts of probiotics might affect the way the immune system works and cause problems by over-stimulating the immune system. Because the effects of probiotics on human health are still being studied, talk to your doctor before taking probiotics and follow the dosing directions on the packaging of any supplement.