The idea of adding a bit of bacteria to your or your child's body may sound creepy-crawly. But if it's bacteria that's good for you, that's exactly what probiotics are.
A recent study found that giving babies probiotics may reduce their risk of developing sensitivity toward allergens. This means that those children may be less likely to develop allergies.
However, the probiotics did not decrease the risk of asthma for children.
The study, led by Nancy Elazab, MD, of the Department of Pediatrics at the University of Miami, aimed to find out whether probiotics might help reduce kids' risk of asthma or a tendency toward allergies of any kind.
Probiotics are live bacteria provided to benefit a person, often to balance the microorganisms naturally occurring in the digestive system.
The researchers searched five medical research databases for any trials up through March 2013 that focused on the effect of probiotic supplements on children's allergy risk.
They only included studies that compared giving probiotics to giving a placebo (fake pill) to children who had been randomly sorted into groups.
The probiotics had to have been provided to children either before birth or after birth within their first year of life with the intention of preventing the development of allergies.
The researchers were able to identify 25 studies that included a total of 4,031 participants.
These were all studies that had been published between 2001 and 2012 and came mostly from Europe, with some from Asia, Australia and New Zealand.
Two of the trials involved giving pregnant women probiotics, and nine studies involved giving the probiotics to children after birth. Ten trials involved giving probiotics both to pregnant women and to their children after birth.
Ten of the studies involved the probiotic Lactobacillus, and the others used probiotic mixtures.
Asthma risk was measured by determining which children had asthma, reported by the parents in five of the studies.
A child's risk of being susceptible to allergies was based on their results to an immunoglobulin E (IgE) test.
This test looks for the concentration of certain antibodies (infection-fighting chemicals) that indicates a child might be more likely to have allergies.
The results of all the studies analyzed together showed that giving probiotics, before or after birth, did result in lower antibodies on the IgE test.
This finding means that a child's likelihood of developing allergies does appear to be slightly reduced when they are given probiotics.
However, giving children Lactobacillus acidophilus rather than other probiotics actually seemed to increase children's risk of being sensitive to certain allergies.
In addition, the use of probiotics did not appear to decrease children's risk of asthma or wheeze at all.
The researchers therefore concluded that giving babies probiotics might reduce the risk of developing allergies.
But the probiotics don't appear to help with lowering a child's risk of developing asthma.
The study was published August 19 in the journal Pediatrics.
The research used no external funding. The authors declared no conflicts of interest.