Researchers from the University of Turin randomly gave 83 infants either a daily dose of probiotic Lactobacillus reuteri 30 minutes after feeding, or simethicone, a pharmaceutical control. After 7 days, the scientists reported that the average crying times of the probiotic infants were down 21 percent, from 197 minutes a day to 159 minutes a day, according to the mothers, while the crying times of the control group were only reduced by 10 percent; from 197 minutes per day to 177. After 28 days, the crying times had dropped 75 percent (51 minutes per day) for the probiotic group and 26 percent (145 minutes per day) 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," reported lead researcher Francesco Savino.
The researchers report that the exact mechanism by which the benefits were achieved is not clear. The theory is that the probiotics may have an anti-inflammatory effect on the intestines, which might subsequently modify immune responses and gut movement.
There are some limits to the study: It was an open, non-blind trial with different doses given to each group. Additionally, simethicone is not a true placebo, but rather a commonly used colic treatment, and Savino said that all participants were breastfed, so the effect of the probiotic on colicky formula-fed infants is not known.
"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," the researchers wrote. "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."
Probiotic bacteria are most often found in foods in the refrigerated areas of the grocery store -- heat can destroy the bacteria -- in dairy products such as yogurt.
Up to 28 percent of newborn babies experience colic, said the report, and it is a common issue within the first three months of life for an infant.