The cause of colic, traditionally defined as inconsolable crying for at least three hours a day, on at least three days in a week and lasting for at least three weeks, isn't clear. It affects up to 28% of babies under three months of age.
Causes are "most likely multifactorial," Dr Savino noted, and may include social and psychological factors, as well as allergies to certain foods, including cow's milk. He added that recent research suggests that babies with colic have an abnormal balance of bacteria in their guts.
Savino and his team had previously tested the probiotic Lactobacillus reuteri against simethicone, the anti-gas remedy found in over-the-counter medications, and found L. reuteri was much more effective in improving colicky symptoms.
Parents gave their babies five drops of the active probiotic, a suspension of freeze-dried L. reuteri in oil, or a placebo consisting of the same oil minus the bacteria, once a day a half-hour before feeding the baby in the morning. All of the infants were exclusively breastfed and mothers were asked to abstain from drinking cow's milk during the three week test.
At the beginning of the study, the 25 babies in the probiotic group were crying for 370 minutes a day, on average, compared to 300 minutes for the 21 babies in the placebo group.
On day 21, babies in the probiotic group averaged 35 minutes of crying a day, compared to 90 minutes for the placebo babies.
The researchers also tested stool samples from the infants before and after treatment and confirmed an increase in the probiotic bacteria among the infants given the supplement; these babies also showed a reduction in the amount of E. coli in their stool and less ammonia. Theories about the causes of colic include the possibility that an over abundance of E. coli in the intestines of colicky babies could produce excess gas.
The probiotic might help babies by improving their gut function and calming intestinal nerves. The considerable decrease in crying time among the babies who received the placebo might be attributable to the mothers' milk-free diet or just growing out of the colicky stage, as most babies eventually do.
Did your baby have colic? What did you do?