Benefits of Probiotics Reviewed

Am Fam Physician. 2008;78:1073-1078.

Probiotics are live microorganisms that are ingested in amounts sufficient to benefit the health of the host. Although probiotics may be widely used for a variety of conditions, available evidence supports their use only for a small number of conditions.

Probiotics may have several mechanisms of action underlying their benefits. In preventing and treating gastrointestinal tract infection, probiotics may be helpful because of direct competition between pathogenic bacteria in the gut and immune modulation and enhancement. Probiotics may affect early development of immune tolerance during the first year of life, explaining their potential effect in children with atopic dermatitis.

Study Highlights
Probiotics used most widely and tested most rigorously include Lactobacillus species, Bifidobacterium species, and the nonpathogenic yeast S boulardii,
Probiotics are considered to be safe and effective for the prevention and treatment of antibiotic-associated diarrhea and infectious diarrhea.
Good evidence indicates that probiotics, especially S boulardii and L rhamnosus GG, help prevent antibiotic-related diarrhea.
Good evidence indicates that probiotic treatment of all-cause infectious diarrhea decreases both the duration of illness and the severity of symptoms.
Small studies suggest that in patients with irritable bowel syndrome, probiotic therapy may decrease the severity of pain and abdominal bloating.
Probiotics may help prevent atopic dermatitis in at-risk infants, and some preliminary evidence suggests that symptoms of atopic dermatitis may also respond to probiotic therapy.
Probiotics are sometimes used for vaginal candidiasis, stomach infection with H pylori, inflammatory bowel disease, and upper respiratory tract infections, but evidence is lacking to support these indications.
Frequently used dosages range from 5 to 10 billion colony-forming units per day for children and from 10 to 20 billion colony-forming units per day for adults, depending on the specific microorganism or combination used.
The dosages of S boulardii used in most studies range from 250 to 500 mg/day.
Common adverse effects of probiotics are mild and self-limited, including flatulence and mild abdominal discomfort.
Septicemia and other severe adverse effects of probiotics are rare.
Probiotics should be used only with caution in patients with short-gut syndrome. They should not be given to patients with conditions that severely compromise the immune system.
Available formulations of probiotics include capsules, powder, tablets, liquid, or incorporated into food. These may vary in quality and biological activity and should be obtained from a reliable supplier.

Pearls for Practice
On the basis of good evidence, probiotics are considered to be safe and effective for the prevention and treatment of antibiotic-associated diarrhea and infectious diarrhea. For prevention of antibiotic-related diarrhea, available evidence favors S boulardii and L rhamnosus GG. Probiotic treatment of all-cause infectious diarrhea decreases both the duration of illness and the severity of symptoms.
Small studies suggest that in patients with irritable bowel syndrome, probiotic therapy may decrease the severity of pain and abdominal bloating. Probiotics may help prevent atopic dermatitis in at-risk infants, and some preliminary evidence suggests that symptoms of atopic dermatitis may also respond to probiotic therapy