What Is Probiotic Bacteria?

Nicole Etolen

Probiotic bacteria, often called “friendly bacteria,” are living microorganisms similar to those found in the human digestive tract. They naturally occur in some foods and beverages, such as fermented cheese and certain types of yogurt, and can be produced separately as dietary supplements. Probiotic bacteria are also used in complementary and alternative medicine to aid with digestive disorders.

Sauerkraut contains acidophilus, a probiotic.
Sauerkraut contains acidophilus, a probiotic.

Several different types of food contain probiotic bacteria. Some occur naturally and others are added during manufacturing. Naturally occurring probiotic bacteria date back to ancient times, when they were found in cultured milk products and fermented foods. Other foods that may contain the friendly bacteria include miso, soy beverages, yogurt, and milk.

Probiotic bacteria, which aids in digestion, is available in capsule form.
Probiotic bacteria, which aids in digestion, is available in capsule form.

Élie Metchnikoff, a Russian immunologist, is credited with discovering the benefits of probiotic bacteria in modern times. He developed a theory that B. acidophilus, lactic-acid bacteria typically found in dairy products, could prolong life by preventing “fouling” in the large intestine. Spurred on by Metchnikoff’s research, other scientists began looking at different types of lactic-acid bacteria. One of those scientists, Henneberg, proposed using Lactobacillus acidophilus, found in the human intestinal tract, which went on to become popular throughout the world.

Antibiotics destroy the good bacteria in the body, which can lead to complications.
Antibiotics destroy the good bacteria in the body, which can lead to complications.

Numerous scientific studies have been performed to determine the effectiveness of probiotic bacteria in helping relieve disorders of the digestive system. Results from these studies indicate that probiotics are beneficial at treating diarrhea, particularly if it is caused by antibiotics. Antibiotics work by destroying bacteria, and they rarely discriminate between the good and the bad. Putting good bacteria back into the system may help alleviate the negative symptoms associated with antibiotic medications.

Yogurt is considered a probiotic food.
Yogurt is considered a probiotic food.

Fermenting food with probiotics has also shown to increase the folic acid content of that food. Folic acid, a B-complex vitamin, is an important nutrient, especially during pregnancy. It plays a role in preventing birth defects, including spina bifada, a condition that occurs when the spinal column does not close around the spinal cord. Folic acid may also play a role in keeping the heart healthy and preventing cancer-causing changes in the cells.

Although foods are considered the best source of probiotic bacteria because of the synergistic nature between the ingredients in the food and the bacteria, over-the-counter supplements are also available. Dietary supplements, however, may not be standardized and effects can differ from brand to brand. Less research has been performed on the long-term effects of these types of dietary substances versus the effects of probiotics found in food.

Side effects of probiotic bacteria are typically mild and may include gas or bloating. In rarer cases, patients with underlying medical conditions may develop an infection that needs to be treated with antibiotics. Overstimulation of the immune system or metabolic changes can also occur. Those considering using probiotics as an alternative medical treatment should consult with a physician first.

Probiotic bacteria are similar to those found naturally in the human digestive tract.
Probiotic bacteria are similar to those found naturally in the human digestive tract.

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Discussion Comments


Does anyone find it interesting that the reason we need probiotics is often because the antibiotics we take have destroyed our friendly bacteria? Sometimes it seems like an endless cycle. Where is the middle ground?

Before we get too excited and start buying tons of yogurt and probiotic capsules, we should take a close look at the possible side effects.


Drentel - I wasn't sure about the purpose of probiotics either until my doctor mentioned them as a possible solution to some of my digestive issues. My first question was: what are probiotics? Once she explained, I was willing to give it a try.

Before you buy those capsules you mentioned, you should try foods that give you what you need naturally. Do you like yogurt? I wasn't a fan, but I have found a couple good ones and they are just what the doctor ordered.


So that's what probiotics are. After seeing several commercials about them lately, I was wondering what all the fuss was about. Maybe I should get some probiotic capsules.

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