The researchers, led by Francesco Savino from the University of Turin, randomly assigned 83 infants to either a daily supplement of the probiotic or the pharmaceutical control simethicone, and report that after 28 days the average crying times of the infants in the probiotic group had decreased by about 75 per cent, compared to only 26 per cent for the control group.
"In our cohort, L reuteri improved colicky symptoms in breastfed infants within 1 week, compared with simethicone, which suggests that probiotics may have a role in… infantile colic," wrote Savino.
According to background information in the article, infantile colic is one of the most common problems during the first three months of an infant's life, and can affect up to 28 per cent of newborns. It consists of a behavioral syndrome characterized by excessive and inconsolable crying with no identifiable cause.
The researchers tested the hypothesis that modulation of the gut microflora via oral administration of probiotics could decrease crying time related to infants with colic.
The 41 infants in the probiotic group received a daily dose of 108 colony-forming units (CFU) of L. reuteri (BioGaia) 30 minutes after feeding, while the control group received a daily dose of 60 mg simethicone after feeding. Mothers were asked to follow a cow's milk-free diet, and avoid milk, cream, butter, yogurt, fresh cheese, and biscuits
After seven days of intervention the average crying times of the infants in the probiotic group had decreased by 21 per cent, from 197 to 159 minutes per day, as reported by the mothers, while crying times for the control group decreased by only 10 per cent, from 197 to 177 minutes per day.
At the end of the full 28 days of intervention, the average crying times of the infants in the probiotic group had decreased by 74 per cent, to 51 minutes per day, while crying times for the control group decreased by only 26 per cent, to 145 minutes per day.
The researchers state that no adverse effects were reported by the mothers.
"The present study demonstrated that supplementation with L. reuteri improved colicky symptoms significantly in breastfed infants, compared with the standard therapy with simethicone, within seven days," wrote the authors in the journal Pediatrics.
"The response rate for… L. reuteri was 95 per cent, whereas only 7 per cent of infants responded to simethicone," they said.
The mechanism behind the apparent benefits is not clear, said the authors, but they speculate that the probiotic may contribute to the anti-inflammatory tone of the intestinal environment, which in turn may modify the immune response and the modulating immune responses and movement of the gut.
The study does have several limitations to note, including being an open trial with no blinding, and both interventions had different doses. Also, no true placebo was used - simethicone being chosen since it said to be the most commonly used pharmaceutical for colic.
Also, the infants in this study were all exclusively breastfed and therefore the results cannot be extended to formula-fed infants with colic, said Savino.
"Because this is the first study performed to evaluate the efficacy of probiotic agents for colicky infants, additional research, from clinical observation to microbiologic analysis, is needed to confirm the beneficial effects of L reuteri," said the researchers.
"Moreover, because specific probiotic strains have specific properties and targets in the human intestinal microbiota, exerting different health effects, additional studies might be performed to examine the role of other probiotic species and to identify the ideal strain for… infantile colic."
Most foods containing probiotic bacteria are found in the refrigerated section of supermarkets as the bacteria is destroyed by heat and other processing conditions.
This has given the dairy sector, already used to handling live bacteria for the manufacture of yoghurt, a major advantage in probiotic foods - probiotic drinking yoghurts are currently the fastest growing dairy product in Europe.
Source: Pediatrics January 2007, Volume 119, Number 1, Pages. e124-e130; doi:10.1542/peds.2006-1222 "Lactobacillus reuteri (American Type Culture Collection Strain 55730) Versus Simethicone in the Treatment of Infantile Colic: A Prospective Randomized Study" Authors: F. Savino, E. Pelle, E. Palumeri, R. Oggero, and R. Miniero