Probiotic Supplementation for Infantile Colic: A Meta Analysis
Treating colic in babies has always been a challenge. Many studies have found that probiotics are beneficial. Yet, larger, more recent studies have suggested that probiotics may not be the ideal way to treat colic in babies. The research team at the Franklin School of Integrative Health Sciences addressed this question head-on through a meta-analysis.
Colic is a catch-all term that refers to frequent crying among newborns. To meet the definition of colic, the infant's persistent crying and fussing cannot be explained by any other health condition. So if a baby cries, but has another diagnosis, it is not technically colic. Colic in babies is a widespread problem with 1 in every 4 babies experiencing this condition.
One of the most common natural solutions to colic is supplementation with infant probiotics. Quite a few studies have supported the use of probiotics for colic in babies, demonstrating that probiotics produce a substantial reduction in the total number of minutes that an infant cries each day.
Yet, recent studies produce the opposite result. In the largest study to date, researchers found that probiotics actually increased the total number of minutes each day that a baby cried when compared to a control group. This control group comparison is important because colic naturally resolves on its own. So all of the babies in the study improved, but the babies who did not take probiotics cried less than the infants who did take probiotics.
When this happens, researchers have to solve the puzzle. Do probiotics effectively treat colic in babies? Or do they worsen colic? The process used to answer this question is a type of study known as a meta-analysis. A meta-analysis is a study of studies, which means that we study existing studies rather than patients. This uses advanced analytic techniques to identify why these studies are producing conflicting results.
The purpose of this meta-analysis is to determine whether or not probiotics actually reduce the total number of minutes that an infant cries, as compared to a control group. The team is also looking for factors that would explain why these studies produce differing results on the effects of probiotics on colic in babies.
To ensure that the meta-analysis is comprehensive and includes all of the research on a subject, we conduct extensive searches on databases and communicate with leading researchers in the field. This ensures that we identify all of the studies on probiotics for colic in babies that can be included. This analysis included studies from around the world, ensuring that every clinical trial on treating colic with any type of probiotic was included. To be thorough, we continued this search for several months.
Studies had to include infants who were younger than 3 months of age to be included in the analysis. These infants also had to be officially diagnosed with colic, according to the standard definition of colic first established by Wessel in the 1950s. The probiotics in these studies were administered through supplement drops or as an additive to a bottle of formula. Most of the studies in the analysis were between 3 weeks and a month long, but one of the studies was 90 days long.
All of these studies were analyzed using statistical process that accounts for the size of each study as well as the total effect, which describes the actual result. So this process accounts for studies that show that probiotics reduce colic in babies by large margins as well as small margins. The meta-analysis process also includes steps which look through each of the studies to identify any problems. Certain issues within the studies may cause the findings to show that probiotics are helpful when in fact, they are not. After conducting all of these analyses, we found that the studies included in this meta-analysis do not have those problems.
As anticipated, the studies included in the meta-analysis produced mixed results. One-third of them show that probiotics worsen colic in babies. The other two-thirds found that probiotics are useful for colic in babies. The data revealed that probiotics do reduce the number of days a child cries. The total effect size was substantial: 3.186. This is far above the effect size required to confirm that probiotics do reduce crying time in babies who have colic.
Why Would Probiotics Increase Signs of Colic in Babies?
To solve this riddle, we analyzed individual variables that might explain the difference in outcomes when using probiotics for colic in babies. In a meta-analysis, these are called moderator variables. Proper research standards require that researchers analyze every possible moderator variable to be sure that nothing is missed. When we did that, we found that one moderator variable could explain the difference in the individual studies.
There was one key factor which determines whether or not probiotics help to reduce colic in babies. That factor? Feeding type.
When analytic processes for feeding type were used, we found that probiotics significantly reduce crying time in breastfed babies with colic. Substantially. The total effect size grows to 4.959 when we only look at the effects of probiotics on breastfed babies. But when probiotics are given to bottle-fed babies, the effect size becomes a negative number (-0.50). A negative number means that the intervention worsens the condition. Furthermore, by research definitions, 0.5 is a large effect. In other words, probiotics don't only increase total crying time in babies, they increase total crying time substantially.
Probiotics for Colic in Babies? The Conclusion
This meta-analysis found that probiotics are a useful tool for breastfed babies who have colic. Supplementation helps to reduce total crying time quite a bit, providing much-needed relief. However, for babies who are formula-fed, probiotics actually make things worse. So parents, doctors, nurses, and caregivers who are looking for effective tools to treat colic in babies should first consider how the child is fed before choosing probiotics as a solution. Babies who are formula-fed are better treated with options such as gripe water which are more effective.