Caffeine and Breastfeeding

If anyone needs a little caffeine, it’s a new mom. My labor with Cee took me through two mostly sleepless nights, and when she finally arrived, we took a little time to nurse and get to know one another, and then our whole little family took a long nap. When we woke up, the first thing I did was send my husband to get me a latte. The second thing I did was breastfeed my new baby again. That dose of caffeine felt like good therapy to me, but what about for Cee? Was it good for her?

caffeine structure

Source: Wikimedia Commons

A few weeks ago, I wrote about the safety of caffeine in pregnancy, and several readers wanted to know about the postnatal effects of caffeine – how mom’s caffeine intake might affect her breastfed baby. I promised to take a look at the literature and report back, and so here we are.

 

When you drink a cup of coffee, how much caffeine ends up in your breast milk?

Several studies have examined this question, and although they are small, they give us a general idea of the transfer of caffeine from mom’s blood to her milk. After a cup of coffee, caffeine is rapidly absorbed into mom’s blood and then passively diffuses across the epithelial layers of the mammary gland. Caffeine appears in milk within 15 minutes of consumption and peaks within an hour. The concentration of caffeine in breast milk ends up being about 80-90% of that in mom’s plasma. However, taking into account the amount of breast milk consumed and adjusting for body weight, studies have estimated that the infant receives no more than 10% of the maternal dose of caffeine, and likely much less (see here, here, and here).

Is this amount of caffeine safe for a baby?

Just because levels of caffeine in breast milk are low relative to what adults normally consume doesn’t mean that these amounts are necessarily safe to a baby. Another important factor is how efficiently a baby can metabolize caffeine, and it turns out that newborn caffeine metabolism is really slow. Whereas the half-life of caffeine in adults is around 2-6 hours, it is an average of 3-4 days in newborns and can be even slower in premature babies. In other words, a morning cup of coffee for mom will easily clear her blood by bedtime, but caffeine may linger in her breastfed newborn for much longer. Metabolism gradually ramps up as the baby matures and the necessary enzyme levels come on board, and most babies can metabolize caffeine at rates similar to adults by 5-6 months of age. Continue reading

Breastfeeding, Gluten Introduction, and Risk of Celiac Disease

A study published yesterday in the journal Pediatrics suggests that later introduction of gluten and breastfeeding beyond 12 months both increase the risk of a child developing celiac disease. These new findings add to the already muddy waters of our current understanding of the role of infant feeding in celiac disease.

Photo by Shree Krishna Dhital, via Wikimedia Commons

Celiac disease is an immune response to gluten, a protein found in wheat, barley, and rye. Celiac is characterized by inflammation and damage to the small intestine, leading to symptoms such as diarrhea and digestive pain. In the U.S., celiac disease is present in about 1 in 141 people, although many of these cases go undiagnosed. Infants that develop celiac disease often have poor growth or weight loss, because intestinal damage compromises nutrient absorption. They also may have chronic diarrhea and a swollen, painful belly.

Celiac can usually be treated with a gluten-free diet, but there isn’t a cure for the disease. Multiple genetic markers have been identified for celiac disease, but many genetically susceptible individuals tolerate gluten and never develop symptoms, leading to speculation about other risk factors, including early childhood nutrition.

This latest study was a large, prospective survey of infant feeding practices and development of celiac disease in Norwegian children. Parents were asked when they first introduced gluten and how long they breastfed their babies. Children that developed celiac disease were tracked through Norway’s national medical system. The study included 324 children with diagnosed celiac disease and 81,843 without celiac. The researchers then looked for patterns in the data that might help to explain why some children developed celiac disease and others did not.

There were two major findings to emerge from this study:

  1. Children that had not yet tried gluten by 6 months of age were more likely to develop celiac disease.
  2. Breastfeeding at the time of introduction to gluten did NOT appear to be protective. In fact, breastfeeding for longer than 12 months was associated with an increased risk, although it was borderline significant (P=0.046).

Both of these findings are contradictory to current infant feeding advice in the U.S. The AAP’s Section on Breastfeeding recommends exclusive breastfeeding for about 6 months before introducing solid foods, followed by “continuation of breastfeeding for 1 year or longer as mutually desired by mother and infant.” The same AAP policy goes on to say, “There is a reduction of 52% in the risk of developing celiac disease in infants who were breastfed at the time of gluten exposure.” But this Norwegian study effectively found that following the current advice of the AAP seems to increase a baby’s risk of celiac, not decrease it.

Obviously, we need more information here. And as usual, one study isn’t enough to give us the full picture of what we know and don’t know about this topic.

To understand the evolving hypotheses around celiac disease and infant feeding, we need to go back to Sweden in the mid-1980’s, when the rates of celiac disease in young kids suddenly quadrupled from an incidence of 1 in 1000 births to 4 in 1000 births over just a few years. It was an epidemic, and it appeared to be isolated to Sweden; neighboring countries weren’t affected. What’s more, celiac was showing up in really young kids. The median age of diagnosis during the epidemic was just about a year old. In 1995, celiac disease in Sweden plummeted back to pre-epidemic levels, and the median age of diagnosis increased to 4 years of age. Continue reading

6 Tips for Sweet Newborn Sleep

Nothing can prepare you for the changes in your sleep when you welcome a newborn baby into your family. Experienced parents will issue dire warnings and tell you to sleep while you can during the last few weeks of pregnancy. (And you will think, yeah right, there’s a large boulder resting on my bladder, and sometimes it kicks for good measure.)

But then the baby arrives, and your world changes forever. Sleep disruption is one of the most immediate and dramatic changes associated with parenthood. It isn’t just that you’re getting less sleep; it’s that your sleep is suddenly dependent on this baby sleeping. And even though newborns sleep a lot – as much as 16-18 hours per day – it feels disorganized and unpredictable.

The thing is, babies, even brand new ones, actually do have organized sleep, it just isn’t organized like yours. But under the surface, baby is working towards being more like you in his sleep. During the first few months, you have no choice but to go with the flow and sleep when the baby sleeps (something I was never good at), but it can help to understand the inherent patterns in your baby’s sleep/wake cycles so that they become more predictable. Your goal is to work with your baby’s biology, find some time for your own sleep, and support your baby in his natural development towards more mature sleep patterns.

In the research for my book, I’ve buried myself in research papers on infant sleep, trying to glean some knowledge that can be helpful to parents in these first few months of baby’s life. Here’s what I’ve come up with so far:

1. Understand newborn sleep cycles. Newborn sleep alternates between active and quiet sleep (akin to REM and non-REM sleep in adults). During the first few months of life, infants usually begin each sleep period in active sleep. Then, after about 25 minutes, they’ll transition to a cycle of quiet sleep, also about 25 minutes long. During active sleep, babies will twitch and flail their limbs, grunt and sigh, and maybe even cry a little. Their eyes move beneath translucent closed lids and may even open from time to time. In quiet sleep, babies breathe slowly and rhythmically, and their bodies are still 1,2.

Why care about the biology of sleep? Because it can help you in these practical ways:

  • Babies wake easily from active sleep, so if your baby falls asleep in your arms, wait until you see signs of that deeper, quiet sleep before you try to move him.
  • Around the 45-50 minutes mark, baby will be finishing up that first active/quiet sleep cycle of 45-50 minutes. Transitioning from one cycle to the next can be tricky for a new baby, so if he wakes during this time (particularly if it’s after just one cycle), see if he wants your help returning to sleep before assuming that he’s ready to eat or play.
  • Active sleep is noisy. Parents often mistake the normal vocalizations of active sleep as the baby waking, and in their efforts to soothe the baby, they’ll actually wake him up. If you think your baby is waking up, pause and watch him for a moment. He may just be dancing in his sleep, or he might be waking briefly only to return to sleep on his own.

IMG_42252. Help your baby find a rhythm. We are adapted to Earth’s 24-hour cycle of light and dark, and our physiological circadian rhythms help us to feel awake during the day and sleepy at night. Newborn babies, on the other hand, sleep just as much during the day as they do at night. It takes them some time to develop rhythms to match our day/night cycle. You can help by sending baby strong environmental and social cues about day and night. Continue reading

Breastfeeding a Toddler? Should You Be Concerned About Iron Deficiency?

You may have heard about a study published in Pediatrics last week (Maguire et al. 2013) showing an association between iron deficiency and breastfeeding beyond a year. If you’re breastfeeding a toddler, or considering it, you might be wondering if you should be worried about iron deficiency. There is very little research on breastfeeding beyond a year in developed countries, so this study is worth a closer look. (If you’re interested, I’ve written before about some of that research, my own reasons for choosing to breastfeed beyond a year, and my experience of weaning my two-year-old.)

What This Study Shows

This was a cross-sectional study of children ages 1-6 in Toronto, Canada. Blood samples were taken from 1647 children, and their mothers were asked, “How long has your child been breastfed?” We always have to be cautious about studies based on parental recall. However, research shows that mothers actually answer this question with good accuracy (Li et al. 2005). Of the children in this study, 93% had been breastfed at all, and median breastfeeding duration was 10 months. Twenty-seven percent of children were breastfed for more than one year, and 4% breastfed for more than two years.

The children’s blood samples were analyzed for serum ferritin and hemoglobin. Serum ferritin reflects the amount of iron stores available for use by the body, so it can be used to assess iron deficiency. If an iron deficient child also had low hemoglobin, he was diagnosed as having iron deficiency anemia. In this study, the prevalence of iron deficiency was about 9%, and 1.5% had iron deficiency anemia, findings similar to other studies in developed countries (Baker et al. 2010, full text here).

This study showed that kids that were breastfed for longer were more likely to be iron-deficient. Each month of breastfeeding beyond baby’s first birthday increased the risk of iron deficiency by about 5%. Children who were breastfed for longer than a year were estimated to have 1.7 times the odds of being iron deficient than those breastfed for less than a year. Continue reading

Weaning My Toddler

So, I have some more big news to catch you up on. I weaned Cee a few weeks ago, soon after her second birthday. I took a few notes along the way, but I never pulled it together to post on the blog about it. I thought I’d share some of those notes here and reflect back on our experience.

Cee may be weaned, but she still nurses her own baby all the time.

Cee may be weaned, but she still nurses her own baby all the time.

11/24/12

Tonight, I nursed my baby girl for the last time. She’s not so much of a baby anymore. She turned two last week. But I savored the feeling of her curled into my arms. I noticed how her long eyelashes cast a shadow across her cheeks and how soft her face looked, the tension of the day melted away.

I remembered nursing her in those early days, when her eyelids were still translucent, tiny blood vessels visible. I remembered how she would be frantic to nurse one second and peaceful the next, her little hand clasped in a fist, resting on the top of my breast.

Cee and I started talking about weaning a few weeks ago. We usually read books while we nurse, and lately I’d noticed that she was so enthralled with the books that she could hardly nurse. I’d turn a page, and she would break her latch to look closer at a picture, pointing something out to me. We were going through the motions because we always had, but nursing didn’t feel that important to either of us anymore. It felt like it was time to make this change.

We had been down to nursing just at naptime and bedtime since the summer. We dropped the naptime feeding first. All fall, Cee had gone down just fine without me and my milk at daycare and with Husband, and there were only a couple of days of brief protest over this change.

Down to just nursing at bedtime, Cee and I talked about how Mama didn’t have very much milk anymore. We talked about how babies (like our friends’ 3-month-old) need a lot of milk, but kids like Cee eat lots of good food and can drink their milk in a cup. We talked about how we love snuggling and nursing, too. I guess I wanted a chance for us both to appreciate our final days of nursing.

A couple of days ago, Cee watched me as I undressed for a shower. She pointed at my naked breasts and said, “Milk?” Continue reading

Why Consider Delayed Cord Clamping?

I first heard about delayed cord clamping as a doctoral student in Nutrition at UC Davis. One of my professors, along with her graduate students, was conducting research on delayed cord clamping in Mexico. Their findings were exciting, and their research was eventually published in the Lancet [1]. I remember being impressed that a simple change in protocol at the birth of a baby – effectively, a non-intervention – could have a profound effect on that baby’s health.

Fast-forward five years, when I was pregnant with Cee in 2010. My OB was an attending physician at an academic hospital and very knowledgeable. However, even she was skeptical when I told her that I was interested in delayed cord clamping. I emailed her a stack of journal articles showing that, at least in an uncomplicated delivery, the benefits outweigh the risks. She was convinced, and we agreed to delay clamping, providing everything went smoothly at the delivery. In the couple of years since Cee’s birth, I think delayed cord clamping has become more mainstream and in some cases, it has become standard protocol. Still, in many hospitals, you may need to advocate for delayed clamping or at least be prepared to discuss the risks and benefits with your OB or midwife.

What exactly do we mean by delayed cord clamping?

Wikimedia Commons

Delayed cord clamping means waiting 2 to 3 minutes after the delivery of an infant before clamping and cutting the umbilical cord. During this time, blood continues to pulse from the placenta to the baby until the pulses naturally stop around 3 minutes. The transfer of blood from the placenta to the baby is most effective if the baby is placed on the mother’s abdomen or lower.

What are the benefits of delayed cord clamping?

Research has found that delayed cord clamping allows 20 to 40 mL more blood to pulse from the placenta to the newborn, carrying with it an additional 30 to 35 mg of iron [2].  As a result, babies have higher newborn hemoglobin, lower risk of anemia at birth and through 2-3 months, and higher iron status and storage through 6 months of age [2, 3].

Delayed cord clamping gives your baby more iron. Why is this important? The extra iron is stored and becomes your baby’s main source of iron until she starts eating solid foods, particularly if you breastfeed. Your baby will use that iron to form red blood cells and transport oxygen, to build muscle, and to develop her brain cells. Severe iron deficiency can cause anemia, but iron deficiency during infancy (even without anemia) also increases the risk of cognitive, motor, and behavioral deficits that can last into adolescence [4-6].

How much stored iron do babies have at birth? That depends. Because the final 8 weeks of pregnancy are most important for iron storage, babies born prematurely can really come up short in iron. Size also matters; big babies are born with more iron stores than their smaller peers. Finally, maternal iron deficiency seems to increase the risk that baby will become iron deficient later in infancy. Depending on these factors, most babies will use up their stored iron between 4 and 8 months of age, after which they’ll need to get iron from fortified formula, iron supplements, or solid foods [8].

This can pose a real problem for exclusively breastfed babies, especially since both the AAP and WHO recommend waiting until babies are 6 months old to begin introducing solid foods. Breastfed babies are at higher risk for iron deficiency than those fed formula, because formula is fortified with iron. Breast milk, on the other hand, is very low in iron. (Why is breast milk so low in iron? I ruminate about that in this post.) Although breastfed babies are very efficient at absorbing that little bit of iron, the quantity is still too small to meet their needs once their iron stores have been depleted. The AAP estimates that U.S. infants that are exclusively breastfed have a 20% risk of iron deficiency by 9-12 months of age [7].

Delayed cord clamping can give babies an extra 1-3 months of iron stores to help bridge their transition from exclusive breastfeeding to solid foods [8]. This can be especially helpful for breastfed babies that are a little slow to start solid foods. Other mammals do not rush to clamp the cord immediately after birth and therefore also get that extra dose of iron to baby before cutting her off from mom’s supply. However, immediate cord clamping does not mean your baby is destined to be iron deficient – it just increases the likelihood that she will need a boost from iron supplements and/or iron-fortified foods.

An added benefit of delayed cord clamping is that it may protect your baby from lead poisoning. One study found that in breastfed infants at risk for lead exposure in Mexico, delayed cord clamping was associated with lower blood lead levels than immediate clamping [9]. This effect is probably related to the improvement in baby’s iron stores, since iron deficiency increases lead absorption. The CDC estimates that 4 million U.S. households have children exposed to lead, so this benefit has the potential to be very relevant to these kids.

Delayed cord clamping is likely even more important for preterm infants, and in fact, is beginning to be adopted by hospitals as general protocol. Preemies are at higher risk for iron deficiency. Delayed cord clamping improves hematocrit and reduces anemia and the need for blood transfusions in these babies [10]. In one trial, it also improved motor development in 7-month-old baby boys who were born prematurely [12]. In another, it increased oxygenation of brain tissue in newborn preemies [13]. Delayed cord clamping has also been shown to decrease the incidence of intraventricular hemorrhage and late-onset sepsis in preemies [10, 11]. Many of these studies used only a 30-45 second delay in cord clamping, but these benefits were observed even with this short delay.

Are there risks to delayed cord clamping?

To date, there is no evidence for significant risks to the mother or the baby associated with delaying cord clamping by 2-3 minutes. Until 2007, early cord clamping was part of the WHO protocol for preventing maternal postpartum hemorrhage, leading many practitioners to believe that late clamping might increase maternal bleeding. However, studies have found that this is not the case [14], and the WHO modified their protocol to reflect this evidence.

Delayed cord clamping does not increase an infant’s risk of jaundice, elevated bilirubin, or the need for light therapy [2, 3]. Some studies have found that delayed cord clamping increases the risk of polycythemia in newborns. Polycythemia occurs when infants have too many red blood cells in circulation – it is the opposite of anemia. However, infants with delayed cord clamping that were diagnosed with polycythemia had no symptoms and did not require treatment. Polycythemia may be a normal outcome of delayed cord clamping in some babies, and as far as we know, it does not appear to pose a health risk in these babies [2].

One other common objection to delayed cord clamping is that it is unnecessary in a developed country, because iron deficiency and anemia are only problems in developing countries. Quite simply, this is not the case. Approximately 10% of toddlers in the U.S. are thought to be iron-deficient [15]. A study in Sweden, a country with a very low prevalence of anemia, still found benefits of delayed cord clamping in this advantaged population [3].

When is delayed cord clamping not appropriate?

If a baby is born in distress and in need of resuscitation to help her breath, delaying cord clamping takes a back seat. Babies in distress need immediate attention, and it may not be practical to care for them while the cord is still attached. To get an idea of how quickly pediatricians need to assess newborn health and take appropriate action, check out their guidelines for newborn resuscitation. As more is learned about the benefits of delayed cord clamping, pediatricians may adjust their protocols to do some procedures at the bedside, allowing the cord to remain attached. In the meantime, it is my opinion that we should let them do their jobs and not ask them to practice outside of their comfort zone when it comes to caring for newborn babies. If the cord is clamped immediately, you can make up for the lost iron by giving your baby an iron supplement or feeding her iron-rich foods when she is ready for solids.

Other resources:

The Academic OB/GYN blog, written by Dr. Nicholas Fogelson, has several articles on delayed cord clamping, as well as links to a 50-minute Grand Rounds video, which is very informative. Squintmom also has a nice, well-cited article on the topic. Links to cited studies are included in the reference list below.

REFERENCES

1.  Chaparro, C.M., L.M. Neufeld, G. Tena Alavez, R. Eguia-Liz Cedillo, and K.G. Dewey. Effect of timing of umbilical cord clamping on iron status in Mexican infants: a randomised controlled trial. Lancet. 367(9527): p. 1997-2004. 2006. Link (abstract)

2.  Hutton, E.K. and E.S. Hassan. Late vs early clamping of the umbilical cord in full-term neonates: systematic review and meta-analysis of controlled trials. JAMA. 297(11): p. 1241-52. 2007. Link (full text available)

3.  Andersson, O., L. Hellstrom-Westas, D. Andersson, and M. Domellof. Effect of delayed versus early umbilical cord clamping on neonatal outcomes and iron status at 4 months: a randomised controlled trial. BMJ. 343: p. d7157. 2011. Link (full text available)

4.  Hurtado, E.K., A.H. Claussen, and K.G. Scott. Early childhood anemia and mild or moderate mental retardation. Am J Clin Nutr. 69(1): p. 115-9. 1999. Link (full text available)

5.  Lozoff, B., E. Jimenez, J. Hagen, E. Mollen, and A.W. Wolf. Poorer behavioral and developmental outcome more than 10 years after treatment for iron deficiency in infancy. Pediatrics. 105(4): p. E51. 2000. Link (full text available)

6.  Sherriff, A., A. Emond, J.C. Bell, and J. Golding. Should infants be screened for anaemia? A prospective study investigating the relation between haemoglobin at 8, 12, and 18 months and development at 18 months. Arch Dis Child. 84(6): p. 480-5. 2001. Link (full text available)

7.  AAP. Pediatric Nutrition Handbook. 6th ed, ed. R.E. Kleinman. Elk Grove Village, IL: American Academy of Pediatrics. 2009.

8.  Chaparro, C.M. Timing of umbilical cord clamping: effect on iron endowment of the newborn and later iron status. Nutr Rev. 69 Suppl 1: p. S30-6. 2011. Link (full text available)

9.  Chaparro, C.M., R. Fornes, L.M. Neufeld, G. Tena Alavez, R. Eguia-Liz Cedillo, and K.G. Dewey. Early umbilical cord clamping contributes to elevated blood lead levels among infants with higher lead exposure. J Pediatr. 151(5): p. 506-12. 2007. Link (abstract)

10.  Rabe, H., G. Reynolds, and J. Diaz-Rossello. A systematic review and meta-analysis of a brief delay in clamping the umbilical cord of preterm infants. Neonatology. 93(2): p. 138-44. 2008. Link (abstract)

11.  Mercer, J.S., B.R. Vohr, M.M. McGrath, J.F. Padbury, M. Wallach, and W. Oh. Delayed cord clamping in very preterm infants reduces the incidence of intraventricular hemorrhage and late-onset sepsis: a randomized, controlled trial. Pediatrics. 117(4): p. 1235-42. 2006. Link (full text available)

12.  Mercer, J.S., B.R. Vohr, D.A. Erickson-Owens, J.F. Padbury, and W. Oh. Seven-month developmental outcomes of very low birth weight infants enrolled in a randomized controlled trial of delayed versus immediate cord clamping. J Perinatol. 30(1): p. 11-6. 2010. Link (full text available)

13.  Baenziger, O., F. Stolkin, M. Keel, K. von Siebenthal, J.C. Fauchere, S. Das Kundu, V. Dietz, H.U. Bucher, and M. Wolf. The influence of the timing of cord clamping on postnatal cerebral oxygenation in preterm neonates: a randomized, controlled trial. Pediatrics. 119(3): p. 455-9. 2007. Link (full text available)

14.  McDonald, S.J. and P. Middleton. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes. Cochrane Database Syst Rev. (2): p. CD004074. 2008. Link (abstract)

15.  Baker, R.D. and F.R. Greer. Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age). Pediatrics. 126(5): p. 1040-50. 2010. Link (full text available)

(An earlier version of this post was published here, where it was hardly noticed. Maybe I’m too conservative for that crowd. Regardless, I’m having a hard time keeping my head above the water with teaching this term, much less find time to research and write sciency posts. I miss it. A lot. Teaching is good, but not as much fun. I’ll be back soon, promise.)

Tummy Troubles, Colic, and Mama’s Diet

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. Continue reading

Why Care About Breastfeeding Research?

Since becoming a mom, and especially since starting this blog, I have paid particular attention to new breastfeeding research. After all, my training is in nutrition, and breast milk is one of the most interesting foods around. Plus, I’m currently lactating and still breastfeeding my daughter a few times per day, so it’s on my mind.

When I look back at the papers that I have covered and those that I find on other blogs and media outlets, I notice that many focus on how breastfeeding improves outcomes in babies.

But I also notice that when I blog about breastfeeding research, I have to spend a big chunk of the piece talking about the limitations of the study. Breastfeeding research – at least when conducted in humans – will always have big limitations that require disclaiming and explaining. The problem is that it is impossible to randomize breastfeeding trials or to “blind” the subjects to feeding type. It is difficult to know, despite the fanciest statistical methods, if it is breast milk that makes those babies thinner, smarter, stronger, cry more, etc, or if there are other factors at play in this complex thing called human life. Sometimes, by the time I’ve listed the problems with interpreting a breastfeeding study, I wonder if these findings were actually meaningful, and I’m sure my readers feel the same way.

Elsewhere around the Internet (not so much on my blog), I often see comments to this effect on articles about the latest research on the benefits of breastfeeding:

“Another useless study. Obviously we mammals were meant to feed our babies breast milk. I don’t know why scientists waste their time and our money with this stuff.”

Why bother doing more research on outcomes associated with breastfeeding? It is pretty clear that breastfeeding is a great way to feed an infant. Maybe it is time to stop oohing and awing over breast milk. Continue reading

Bottle-feeding and Obesity Risk

Source: Wikimedia Commons

A study published this month in Archives of Pediatric and Adolescent Medicine looks at the relationship between infant feeding practices and weight gain (1). Breast milk vs. formula? Nope, it isn’t that simple.

Led by Dr. Ruowei Li of the CDC, this prospective longitudinal study tracked feeding and weight gain in 1900 infants during their first year of life. Each month, mothers were asked how they fed their babies in the last 7 days, and from their replies, infants were grouped into the following categories across ages:

  1. Breastfed only
  2. Breastfed and human milk by bottle
  3. Breastfed and formula by bottle
  4. Human milk by bottle only (i.e. exclusive pumping)
  5. Human milk and formula by bottle
  6. Formula by bottle only

The mothers in this study were mainly white, married, and had at least a high school education. A third were on WIC. About 50% were overweight or obese. Statistical methods were used to adjust the findings for a range of maternal factors, including BMI, as well as infant sex, gestational age, birth weight, and age of solid food introduction.

The most important finding from this study was that infants fed by bottle only – whether fed formula or breast milk – gained more weight than those fed breast milk at the breast. Continue reading

The Apparent Breastfeeding Paradox: What is optimal nutrition for a premature baby?

Last week, I wrote about some of the unique challenges (and one potential solution) to breastfeeding a baby born prematurely. Another study recently published in BMJ Open provides more food for thought on breastfeeding preemies (1; full text available here).

A team of French researchers examined the relationship between breastfeeding, growth, and neurodevelopment in two observational cohorts of babies born very prematurely, at less than 32 or 33 weeks of gestation.

Between the two cohorts, a total of 2925 very preterm infants were included in the study. These babies were in the hospital for 50-60 days before they were allowed to go home. In the two cohorts, 19% and 16% of babies were breastfeeding at the time of discharge from the hospital. The study looked at associations between type of feeding at discharge (breast milk or formula), growth during hospitalization, and growth and neurodevelopment at 2 and 5 years of age.

Source: Wikimedia Commons

What were the findings? In these cohorts, formula-fed babies had gained more weight by the time they were discharged from the hospital. However, at 2 and 5 years of age, the formula-fed babies scored lower on neurodevelopment assessments compared to the breastfed babies. Breastfed babies also had greater head circumferences by 2 and 5 years of age, suggesting improved brain development, and they appeared to catch up to formula-fed babies in height and weight. Continue reading