Acidophilus and Other Probiotics

Health Benefits, Uses, Side Effects & More

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What are Probiotics?

Probiotics are live microbial organisms that are naturally present in the digestive tract and vagina.

The digestive tract maintains a balance between healthy and potentially harmful micro-organisms. Healthy micro-organisms, also called microflora, are residents of the digestive tract that have a protective role in our bodies. There are over 400 species of microorganisms in the human digestive tract, including Lactobacillus and Bifidobacterium.

Health Benefits of Probiotics

A number of preliminary studies suggest that probiotics may offer a variety of health benefits.


A literature review on probiotics found 185 studies published between 1980 and 2004. The most commonly studied condition was diarrhea (in 41 or 22 percent of the 185 studies).

Seven studies looked at probiotic use in adults, focusing on the strains Lactobacillus reuteri, Lactobacillus GG, L casei, L acidophilus, and Saccharomyces boulardii. Although they varied in dose and probiotic strain, in six of the studies, probiotics shortened the course of diarrhea or decreased its severity.

Related: Saccharomyces boulardii: What You Need to Know

Many studies have looked at probiotic use in children. Once again, there is a wide range of doses and probiotic strains. The most commonly used strains were Lactobacillus acidophilus, L casei, L GG, and Bifidobacteria. In 20 of the studies published between 1980 and 2004, all of the studies found an improvement.

Seven out of 12 controlled trials reported a definite prevention of antibiotic-associated diarrhea. In addition, a meta-analysis looked at 9 randomized, double-blind, placebo-controlled trials with a total of 1214 patients. Six of the nine trials showed a significant benefit of probiotics.


Probiotics are thought to combat oxidative stress, said to play a role in the development and progression of diabetes.

 A study assessed the effectiveness of probiotics and yogurt on blood glucose and antioxidant status in people with type 2 diabetes.

For the study, 64 people with type 2 diabetes were assigned to two groups. One group took 300 grams/day of probiotic yogurt containing Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and people in the control group took 300 grams per day of conventional yogurt for six weeks.

Fasting blood tests, 24-hour diet recalls and anthropometric measurements were collected before and after the six-week study period.  After six weeks, fasting blood glucose and hemoglobin A1c were decreased compared to the baseline measurement and glutathione peroxidase, erythrocyte superoxide dismutase, and total antioxidant status increased compared to the control group, indicating that probiotic yogurt may be a promising functional food for the management of diabetes.

Functional Bowel Disorders

Studies on probiotics for functional bowel disorders have had inconsistent results, which might be due to differences in probiotic strains used in the studies.

study examined the probiotic bacterias Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 twice a day in people with functional bowel disorders excluding constipation.

Primary outcomes were relief of gastrointestinal symptoms and treatment satisfaction.  Secondary outcomes were changes in the severity of symptoms, well-being, and quality of life.

After four and eight weeks, abdominal bloating improved in the group taking the probiotics compared with those taking the placebo.

Common Uses for Probiotics

Sources of Probiotics

Probiotics can be found in capsule, liquid, powder, or tablet form. Acidophilus drinks can be found in health food stores and some grocery stores and Asian grocers.

Probiotics can also be found in cultured dairy products such as yogurt or kefir, however, the number of live organisms varies greatly from product to product due to differences in processing methods. Fermented foods such as sauerkraut also contain probiotics.

Related: Kefir: What You Need to Know

Once ingested, probiotics colonize the intestines and other parts of the body and can sustain themselves unless they are destroyed by antibiotics or other factors.

Although they are thought to be essential for health, because they can sustain themselves in the body under normal circumstances, there is no recommended daily intake of probiotics.


"Prebiotics" are also thought to improve the balance of probiotics in the intestines. They are non-digestible carbohydrates that stimulate the growth of beneficial bacteria in the intestines. Sources of prebiotics include fructo-oligosaccharides (FOS) and inulin, found in onions, asparagus, chicory, and banana. FOS is also available as a supplement and is sometimes combined with probiotic dietary supplements.


Side effects of probiotics may include mild, temporary digestive complaints, such as gas and bloating.

People who are immunosuppressed should seek medical advice before using probiotics. It is possible that the probiotic itself may cause a serious infection. One death was reportedly linked to probiotic use in a person taking immunosuppressant medication.

Probiotics may interact with immunosuppressant medication (see above). Probiotics are recommended by some health practitioners during and/or after antibiotic use.

Supplements haven't been tested for safety and keep in mind that the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established. You can get tips on using supplements here, but if you're considering the use of collagen supplements for anti-aging purposes or in the treatment of a condition, talk with your primary care provider first. 

Disclaimer: The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is not meant to cover all possible precautions, drug interactions, circumstances or adverse effects. You should seek prompt medical care for any health issues and consult your doctor before using alternative medicine or making a change to your regimen.


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MacGregor G, Smith AJ, Thakker B, et al. Yoghurt biotherapy: contraindicated in immunosuppressed patients? Postgrad Med J. (2002) 78:366–367.

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Shornikova A.V., Casas I.A., Mykkanen H., Bacteriotherapy with Lactobacillus reuteri in rotavirus gastroenteritis. Pediatr Infect Dis J (1997) 16 : pp 1103-1107.

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