Colic affects about one in five infants in the United States annually and accounts for numerous pediatric visits during the first several months after birth.

Among the many claims of probiotic marketing is that it helps with reduction of colic symptoms but a phase III, double blind, randomized placebo controlled trial published in the British Medical Journal concluded that the use of the probiotic L reuteri for infant colic did not reduce crying or fussing in infants nor was it effective in improving infant sleep, functioning or quality of life.

The results were no different for babies receiving breast milk or formula.

"The role of different intestinal microbes in producing or alleviating colic remains a subject of interest," says Joel Lavine, M.D., Ph.D., professor of pediatrics and chief of pediatric gastroenterology, hepatology and nutrition at Columbia University Medical Center. "Some studies have identified changes in the colonization that are associated with colic, although these changes have not been shown to be causative, and the specific kinds of bacteria potentially responsible have not been identified. Thus far, manipulation of gut colonization by probiotics remains an inexact science and conflicting evidence exists regarding the efficacy of probiotics in improving the problem."

Another under-discussed cause of colic symptoms, transient lactase deficiency (TLD), is known to be a cause of colic in about 38% of cases. Transient lactase deficiency is a temporary insufficiency of lactase enzyme, resulting in temporary digestive discomfort caused by the undigested lactose in breast milk or infant formula, often resulting in excessive crying and fussing, otherwise known as colic.

"Manipulation of bacterial populations in the gut may reduce the amount of gas produced by virtue of reducing lactose malabsorption," adds Lavine. "This problem of lactose malabsorption can be easily resolved by providing lactase to infants who are lacking, by way of commercially available infant drops."

Citation: Sung V , Hiscock H , Tang MLK ,Mensah FK , Nation ML , Satzke C ,et al., 'Treating infant colic with the probiotic Lactobacillus reuteri: double blind, placebo controlled randomised trial', BMJ 2014;348:g2107 DOI:10.1136/bmj.g2107