This question comes from a ScienceofMom reader, who wrote me to ask:

I’m looking for good quality information on whether mom’s diet can really cause tummy trouble in babies, outside of perhaps a milk protein allergy. I’ve seen arguments that it does, but they seem largely anecdotal. Yet my pediatrician has never mentioned the possibility that my diet might be causing my 3-month-old infant to have gas bouts at 4 a.m. or so every. single. night. Instead I’m routinely told that I just need to wait and by 4 months her digestive system will grow up. –KT

Most of us have heard and read that we don’t need to give up any of our favorite foods in order to breastfeed our babies. In general, this is true, and it is an important message. Between sore nipples and engorged breasts during those first few weeks of motherhood, moms need to know that breastfeeding will eventually (usually) be an easy fit to their lifestyle.

There has even been some recent research showing that maternal diet restriction during lactation may increase baby’s chances of developing allergies. If your baby is NOT showing any signs of tummy troubles, your best bet is to eat a balanced variety of whole foods. Think of it as gently introducing your baby to the proteins of the world via your milk.

However, there have been several studies of the effect of mom’s diet on colic symptoms. Approximately 1 in 5 U.S. infants between 0 and 4 months are considered to have colic. The “Rule of Threes” is used to define colic: A colicky baby has incessant, inconsolable crying for at least 3 hours per day on at least 3 days per week, for more than 3 weeks. Crying is usually the worst in the evening hours. {It isn’t clear from K.T.’s note if her baby actually has colic or just gas – they’re not always the same. I’ve focused this post on colic, because that’s where the research is, but I’m willing to speculate that what works for colicky babies may also help babies with milder types of GI discomfort.}

The truth is that we really don’t know what causes colic. It is probably multi-factorial and has different causes in different babies. (For an interesting account of the history of our understanding of colic and how to manage it, check out this article,The Colic Conundrum, from The New Yorker.) However, there are several lines of evidence that colic is related to intestinal immaturity or imbalance. Colicky babies often seem to be gassy and to have GI discomfort, pulling their legs up to their bellies while crying as if in pain. Research has also shown that colicky babies have intestinal inflammation and abnormal gut motility [1]. In addition, we know that proteins from mom’s diet can pass into breast milk, and some babies seem to be allergic or intolerant of these proteins. That’s where the role of mom’s diet comes in.

Cow’s milk appears to be the most common culprit when it comes to food allergies in infants. It has been estimated to occur in about 0.5-1.0% of exclusively breastfed infants [2]. Studies on the relationship between cow’s milk allergy and colic are mixed, however. In one study, 66 mothers of exclusively breastfed colicky infants eliminated cow’s milk from their diets, and “colic disappearance” was noted in more than half of the infants [3]. When the moms later drank cow’s milk again as a test, colic symptoms returned in 2 out of 3 of the babies. Based on this study, cow’s milk allergy or intolerance would seem to be an important cause of colic.

Other studies of cow’s milk elimination were less successful [4]. A recent study of Saudi babies tested 114 colicky babies for cow’s milk allergy with a skin prick test [5]. Only three of these babies tested positive, and when cow’s milk was removed from the mother’s diet, their colic symptoms disappeared. However, of the remaining 111 babies, eliminating cow’s milk from mom’s diet did not reduce their time spent crying.

So depending on which study you look at, cow’s milk allergy seems to be either very common or rather rare in colicky babies. Hmmm. A tricky thing about these studies is that they rely on mothers being thorough about removing every source of cow’s milk protein from their diet, as it can be hidden in lots of processed foods. This may explain the variable results found between studies. Unless moms live in a research center and eat only controlled meals, it is very difficult to conduct these diet studies that rely on mothers choosing foods within the guidelines and reporting their eating habits accurately. (As I write this, I’m having a flash of horror at the thought of what it would look like to bring 100 colicky infants and their mothers to live in a research center for a week or so. Yikes!) And despite the mixed results from these studies, cow’s milk allergy does seem to cause colic symptoms in some babies.

What about other foods? In 1996, Lust and colleagues reported the results of a survey of maternal diet and colic symptoms in 272 exclusively breastfed infants in the U.S. [6]. Mothers were asked to recall their babies’ behavior and their own dietary habits over the past week. Babies were considered to have colic if they showed abdominal cramping (drawing up of legs, appearing to be in pain), irritability, and intense crying. As a group, mothers with colicky babies had greater intake of the following foods: cow’s milk, cabbage, cauliflower, broccoli, onion, and chocolate. If you’re curious, the foods NOT associated with colic symptoms were garlic, green peppers, orange juice, brussel sprouts, dried beans, eggs, carrots, beef, and beer. If you have a colicky baby, choose carrot cake and beer rather than chocolate chip cookies and milk.

A 2005 randomized controlled trial of 47 Australian mothers and their colicky babies tested a low-allergen elimination diet [7]. Moms in the low allergen group cut out dairy, soy, wheat, eggs, peanuts, tree nuts, and fish. The control moms were instructed to eat all of these foods and were specifically provided with a serving of peanuts, chocolate, and a cow+soy milk drink every day. After 7 days on the low allergen diet, babies cried about 90 minutes per day less than the control babies. 74% of the low-allergen babies showed significant improvement in colic symptoms compared to only 37% of controls (P<0.001). In other words, eliminating common allergens from mom’s diet appeared to really help a significant fraction of colicky babies.

This is slightly off topic, but one of the most interesting things I ran into as I researched this question was about probiotics as a treatment for colic. A 2007 study found that colic improved in a dramatic 95% of babies given Lactobacillus reuteri once per day for 1 month [8]. By the end of the month, these babies were crying for only 51 minutes per day! (Not bad for any baby, I’d say.) Another group of babies was given a drug called simethicone (used to treat gas, though has been shown to ineffective). Only 7% of the simethicone babies improved over the month, and they cried 145 minutes per day. All of the moms in this study also avoided dairy, so the benefits of probiotics were above and beyond those from eliminating dairy.

Lactobacillus reuteri are normal endogenous bacteria found in the GI tract and used as probiotics for many years in adults. The benefits of probiotics in infants are thought to come from the formation of a protective barrier against harmful bacteria (“outcompeting” them with good ones) and perhaps by stimulating the maturation of the immune system. Pediatricians may be reluctant to jump on the probiotic bandwagon just yet, but a previous study found no adverse effects of daily dosing of L. reuteri starting at birth and continuing for 12 months [9]. Therefore, it appears to be safe and is certainly worth discussing with your pediatrician.

Colic is serious. Mothers of colicky babies have 10-fold odds of suffering from depression [10]. When babies cry for hours on end, parents become frustrated, exhausted, and may start to wonder what they are doing wrong. It helps to know that the crying won’t last forever (most babies improve when they are 3-4 months old) and that there is often nothing that can be done. However, I think that anything that may help baby – and parents – feel better is worth a shot. If your baby has colic, the research shows that trying an elimination diet and giving baby probiotics may help. Neither are likely to be a quick fix for all babies, but both are worth trying.

From a practical standpoint, eliminating all potential allergens from your diet sounds daunting to me, particularly when I think about how ravenously hungry I was during the first few months of my baby’s life. Peanut butter and jelly sandwiches and whole cow’s milk were standbys for me. Because cow’s milk is the most common infant allergy, it makes sense to try that for a week or so first before you throw the baby out with the bath water and go on a complete elimination diet. If you are considering an elimination diet, here are a couple of resources you may find useful:

The American Academy of Breastfeeding Medicine’s clinical protocol for infant allergies offers a plan for an elimination diet [PDF].

“So, what CAN I eat?” is a blog post written by Diana Cassar-Uhl, IBCLC packed with practical advice and links to delicious recipes for breastfeeding moms on elimination diets.

Did you change your diet while breastfeeding? Did this seem to impact your infant?

REFERENCES

1. Heine, R.G., Gastroesophageal reflux disease, colic and constipation in infants with food allergy. Curr Opin Allergy Clin Immunol, 2006. 6(3): p. 220-5.

2. The American Academy of Breatfeeding Medicine, ABM Clinical Protocol #24: Allergic Proctocolitis in the Exclusively Breastfed Infant. . Breastfeeding Medicine., 2011. 6(6).

3. Jakobsson, I. and T. Lindberg, Cow’s milk proteins cause infantile colic in breast-fed infants: a double-blind crossover study. Pediatrics, 1983. 71(2): p. 268-71.

4. Evans, R.W., et al., Maternal diet and infantile colic in breast-fed infants. Lancet, 1981. 1(8234): p. 1340-2.

5. Moravej, H., et al., Predictive value of the cow’s milk skin prick test in infantile colic. Ann Saudi Med, 2010. 30(6): p. 468-70.

6. Lust, K.D., J.E. Brown, and W. Thomas, Maternal intake of cruciferous vegetables and other foods and colic symptoms in exclusively breast-fed infants. J Am Diet Assoc, 1996. 96(1): p. 46-8.

7. Hill, D.J., et al., Effect of a low-allergen maternal diet on colic among breastfed infants: a randomized, controlled trial. Pediatrics, 2005. 116(5): p. e709-15.

8. Savino, F., et al., Lactobacillus reuteri (American Type Culture Collection Strain 55730) versus simethicone in the treatment of infantile colic: a prospective randomized study. Pediatrics, 2007. 119(1): p. e124-30.

9. Connolly, E., T. Abrahamsson, and B. Bjorksten, Safety of D(-)-lactic acid producing bacteria in the human infant. J Pediatr Gastroenterol Nutr, 2005. 41(4): p. 489-92.

10. Kurth, E., et al., Crying babies, tired mothers: what do we know? A systematic review. Midwifery, 2011. 27(2): p. 187-94.