Probiotics are generally regarded as safe for human consumption. Long-term consumption of probiotics is considered safe and well tolerated.
Some people experience excessive production of gas due to the corrective activity of probiotics in the colon. This is patient-specific and normally will decrease with use. Gradual increase of dosing over time is recommended to minimize this.
Probiotics are contraindicated in people who are hypersensitive to any component of a probiotic-containing product. Lactose-sensitive people may develop abdominal discomfort from dairy products containing probiotics. Caution is advised when using probiotics in neonates born prematurely or with immune deficiency.
No adverse side effects have been reported in the majority of studies reviewed.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Antibiotic (probiotics to reduce related adverse effects)
An increasing number of studies support the use of probiotics as a supplement to antibiotic therapy. Probiotic supplementation during a course of antibiotics may reduce the adverse effects of antibiotics in the intestinal environment. This includes reducing growth of
Helicobacter pylori infection
Antibiotics are the main treatment to eradicate
Atopic dermatitis (eczema)
Probiotics show promise for reducing or preventing atopic eczema/dermatitis syndrome in children. Infants benefit when their mothers take probiotics during pregnancy and breast-feeding. Direct supplementation of infants may reduce incidence of atopic eczema by as much as half. It may also reduce cow's milk allergy and other allergic reactions during weaning. Probiotics may stabilize the intestinal barrier function and decrease gastrointestinal symptoms in children with atopic dermatitis. Children do differ, however, in their responsiveness to specific probiotics.
Liver cirrhosis may be accompanied by an imbalance of intestinal bacteria flora. Probiotic supplementation in cirrhosis patients has been found to reduce the level of fecal acidity (pH) and fecal and blood ammonia, which are beneficial changes.
There is recent evidence that supplementation with
Short-term consumption of probiotic-containing cheese may benefit dental caries. There is also evidence that the probiotic
Diarrhea in children (nosocomial)
Preventive use of
There is tentative support for probiotics to prevent diarrhea in adults and children. Supplementation may benefit HIV-positive men, and yogurt containing
Diarrhea treatment (children)
Probiotics may reduce the duration of diarrhea and related hospital stays in children. Fermented formula and formula supplemented with probiotics may reduce both the number and duration of episodes of diarrhea.
There is evidence that young children (ages 6-36 months) who receive infant formula with
Limited evidence with day care children suggests supplementation with
Probiotics may reduce duration of symptoms in adults and children with infectious diarrhea by 17 to 30 hours. Effective forms include
Irritable bowel syndrome (IBS)
Many varieties and combinations of probiotics have been studied in clinical trials for IBS. Findings frequently report reductions of symptoms including pain, flatulence, bloating and stool frequency. There is some evidence of reduced inflammation. The magnitude of benefit seen in most studies is modest. Not all studies, however, show beneficial effects. More studies are needed to determine the best protocols and what level of benefit can be expected.
One study suggests
Use of probiotic
Nissle 1917 appears to be as effective as the drug Mesalazine, but is not currently available in the United States. A variety of
Only a small number of the variety and combinations of probiotics have been studied in treatment of allergies, mostly with children, teenagers and young adults. Inhalant allergy conditions such as allergic rhinitis (nasal inflammation and discharge) during pollen season have had mixed results. Some studies have found no benefits, while others have found benefit from adding probiotics to fermented milk. There is also evidence that yogurt may improve or prevent recurrence of allergic rhinitis. Studies of allergic skin reactions in infants (allergic dermatitis, atopic eczema) suggest that supplementation - including for lactating mothers - may reduce frequency, symptom levels, and duration. In summary, a definitive role of probiotics for allergic conditions remains unproven, although initial results in studies of children with a variety of preparations are promising.
Combining a probiotic yeast (
As a bacterial reservoir, the nose may harbor many varieties of potentially disease-causing bacteria. There is limited evidence that probiotic supplementation may reduce the presence of harmful bacteria in the upper respiratory tract. More studies are needed to establish this relationship and its implications for health.
Vaginal suppositories containing probiotics may be effective in the treatment of bacterial vaginosis. Eating yogurt enriched with
There is limited evidence suggesting probiotics may help reduce low density
Cardiovascular risk reduction (smokers/atherosclerosis)
One study suggests probiotic supplementation might reduce blood pressure and some biochemical risk factors for cardiovascular disease (leptin and fibrinogen). This implies a possible protective effect against atherosclerosis. However, more studies are needed to confirm such effects.
There is insufficient evidence on which to form conclusions for use of probiotics in collagenous colitis.
Use of probiotics with constipation has had mixed results. One study combining them with food showed a beneficial effect on gastrointestinal symptoms of patients with chronic constipation. However, another study did not show effectiveness in young children. More studies are needed to determine what forms of probiotic and pathways of administration might be effective in constipation.
Evidence regarding benefit in Crohn's disease is mixed. There is preliminary evidence that
There is limited evidence that probiotics may help in acute diarrhea. A study of day care children with mild gastroenteritis found a probiotic combination to reduce duration of diarrhea. A study in adults found that a different formula did not reduce duration, but did reduce frequency of stools. More studies are needed to determine recommendations for probiotic use in acute diarrhea.
Limited data support probiotics for treatment and prevention of antibiotic-associated diarrhea (AAD). Studies have evaluated a variety of probiotics for these uses, including with children. In summary, probiotics are considered a safe and reasonable approach to prevention or reduction of AAD in people undergoing antibiotic therapy. However, larger and better-designed studies are needed for definitive recommendations.
Diarrhea (chronic bacterial overgrowth-related)
There is limited evidence suggesting probiotics might help in treatment of bacterial overgrowth-related chronic diarrhea. More studies are needed to provide guidelines for this use.
Diarrhea (Clostridium difficile)
There is limited evidence suggesting that probiotics may reduce recurrence of
Hepatic encephalopathy (confused thinking due to liver disorders)
Initial studies in minimal hepatic encephalopathy are encouraging. Probiotics and prebiotics may lead to improvement of symptoms and may be an alternative to lactulose for management of this condition in people with cirrhosis. However, more studies are needed to determine the role of probiotics in this condition.
There is conflicting evidence regarding the effects of probiotic-enriched dairy products on lowering blood levels of total cholesterol or low-density lipoprotein ("bad cholesterol"). More studies are needed.
in fermented milk, low-fat milk, or lactose-hydrolyzed low-fat milk may enhance immune function.
Results are mixed regarding the ability of probiotics to reduce infective complications of medical treatment. Reduced incidence of infection has been seen in patients treated for brain injury, abdominal surgery, and liver transplantation. Other studies have shown no such reduction in elective abdominal surgery and critical care patients.
Infections (rotavirus nosocomial)
Supplementation of infant formulas with probiotics is a potential approach for the management of cow's milk allergy, but there is conflicting evidence as to whether it improves digestion of lactose. More research is needed in this area a before a conclusion can be drawn.
Necrotizing enterocolitis (NEC) prevention
Little evidence is available on the effects of probiotics in prevention of NEC. Study results conflict. Further studies are needed to determine the effectiveness of this application.
There is insufficient evidence to draw any firm conclusions. More research is necessary.
Limited evidence suggests a probiotic preparation (VSL#3, containing
Rheumatoid arthritis (RA)
In a small study
Supplementation in preterm and very low birthweight infants
Probiotic supplementation may foster better growth and higher counts of healthful bacteria in the gut of preterm infants.
Urinary tract infection
Vaginal candidiasis (yeast infection)
Probiotics have not been adequately studied for the prevention or treatment of vaginal yeast infections. More research is needed in this area before a conclusion can be drawn.
Bacterial infection (translocation)
Bacterial translocation (passage of bacteria from the gut to other areas of the body where they can cause disease) is of special concern in surgery. Limited evidence suggests that supplementation with probiotics may not reduce this problem.
Diarrhea (HIV patients on antiretroviral therapy)
Probiotic therapy is well tolerated in HIV infected patients on antiretroviral therapy, but may not be helpful for gastrointestinal symptoms.
Probiotics have been used in the vagina immediately after oocyte retrieval during IVF, but they do not appear to have an effect on vaginal colonization or pregnancy rate in IVF cycles.