New Research on Gluten Introduction to Infants and Risk of Celiac Disease

If you’re worried about your child’s risk of celiac disease and wondering when to introduce gluten-containing foods, then you’ll want to know about two new studies published in the New England Journal of Medicine this week.

Gluten is delicious to most of us, but it can be devastating to those with celiac disease. Photo by Adrian van Leen

Gluten is delicious to most of us, but it can be devastating to those with celiac disease. Photo by Adrian van Leen

Celiac disease is an immune response to gluten, a protein found in wheat, barley, and rye. It causes inflammation and damage to the small intestine, and while it can be successfully managed with a gluten-free diet, it is a lifelong disease. (Celiac disease is distinct from non-celiac gluten sensitivity, which is a murky and controversial condition that may not be related to gluten at all.)

I reviewed the research on early infant feeding and risk of celiac disease on my blog about a year ago (Breastfeeding, Gluten Introduction, and Risk of Celiac Disease). I have since received lots of comments and messages from parents concerned about this, so I wanted to be sure to write about these important new studies.

These latest studies dramatically advance our understanding of this topic because they are randomized controlled trials. Both started with a group of babies already identified as being high-risk for celiac disease, randomly assigned them to different time of introduction of gluten, and then tracked their development of the disease. Previous studies were all observational, thus only able to identify associations between variables, and were limited by confounding factors and other sources of bias.

The first study was led by researchers in the Netherlands but included children born in 7 European countries and in Israel. 944 babies were identified as being high-risk for celiac based on a genetic predisposition (HLA genotype) and having a first-degree relative (parent or sibling) with celiac. The babies were randomized to two groups, and one group was given a small amount (100 mg) of gluten starting at 4 months of age, while the control group was given a placebo and instructed not to introduce gluten until 6 months, at which point parents in both groups were advised to gradually introduce gluten-containing foods. The incidence of celiac disease was tracked through 3 years of age, with all suspected cases confirmed with an intestinal biopsy. Overall, about 5% of the study participants developed celiac disease by age 3, and it made no difference whether gluten was introduced at 4 or 6 months. It also made no difference whether the babies were breastfed (exclusively or not) or currently breastfed at the time of gluten introduction.

The second study was conducted in Italy and had a similar design but instead compared gluten introduction at 6 vs. 12 months. Continue reading

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

The Magic and the Mystery of Skin-to-Skin

I meant to do skin-to-skin with Cee after her birth, I swear. It was in my birth plan. But after a long labor, Cee was born blue and limp, and the understandable concern about her health trumped any ideas I’d had about optimizing our postpartum experience. Cee was whisked away to a warmer on the other side of the room and encircled by the NICU team. Thankfully, I heard her cry within a few moments, and she was in my arms soon after. But by then, she was wrapped in a pink and blue flannel blanket, and I was too overwhelmed and taken with her to think of unwrapping her. Instead, I held her, and we gazed into each other’s eyes. She started rooting and was nursing within a couple of minutes. It was a magical first meeting, and it wasn’t until later that I realized that I’d screwed up and forgotten to do skin-to-skin.

IMG_3113

What’s wrong with this picture? (besides the fact that I hadn’t slept or brushed my hair in 48 hours)

I’ve been researching this topic for a chapter in my book about the postpartum period. I’m writing about what we know and don’t know about getting to know our newborns, establishing breastfeeding, rooming in, and yes, skin-to-skin. When I started working on this chapter, I thought the skin-to-skin thing was a slam-dunk, maybe even too obvious to be of much interest to my readers.

Modern-day interest in skin-to-skin, also called kangaroo care, began in 1978 in the NICU at San Juan de Dios hospital in Bogotá, Columbia. For every 10 premature babies born there, only 3 survived. There weren’t enough incubators or nurses. Babies were tucked two to three at a time in incubators, and infections were rampant. Parents weren’t encouraged to be involved in the babies’ care, and having little emotional connection to them, many abandoned their sickly babies at the hospital. Kangaroo care was a desperate attempt to care for these vulnerable babies. Mothers were essentially asked to be their babies’ incubators, holding them skin-to-skin 24 hours per day and breastfeeding on demand.

The results were astounding. The kangaroo care babies in Bogotá grew well, were more likely to be breastfed, and were less likely to get severe infections or be abandoned. The power of kangaroo care for low birth weight babies has since been confirmed in multiple studies. A 2011 Cochrane review concluded that skin-to-skin helps stabilize premature newborns, reduces mortality, infections, hypothermia, and length of stay in the hospital. These benefits are particularly clear in developing countries, but many hold in industrialized nations as well.

With the impressive success of skin-to-skin care for preemies, it seemed natural to assume that full term babies would benefit from it as well. But the research in this area is disappointing. 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

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

Breastfeed for your child’s future… as a long-jumper?

I try to stay abreast of the latest in breastfeeding research (hehe), and this paper, published last week, caught my eye:

Exclusive breastfeeding duration and cardiorespiratory fitness in children and adolescents. (Labayen et al., American Journal of Clinical Nutrition)

Was it possible that breastfeeding BabyC could affect her level of fitness as a teenager? I was intrigued.

The study tested cardiovascular fitness on a stationary bike in about 2000 children and teenagers from Sweden and Estonia. The kids’ mothers were asked to recall if they breastfed their children, and if so, for how long (<3 months, 3-6 months, or >6 months). Children that were fed a mix of breast milk and formula for any period were eliminated from the study.

The researchers found that breastfed kids had about 5% greater cardiovascular fitness than those fed formula, and fitness was highest in children who had been breastfed exclusively for at least 3 months. This finding held true even after the researchers adjusted for country, gender, age, puberty, BMI, birth weight, physical activity level, maternal BMI and maternal education.

A 5% increase in cardio fitness may not seem like much, but it is actually rather impressive when you consider all the other factors that are involved. Genetics are thought to explain about 50% of fitness, and body weight and activity level (how much aerobic activity a person routinely does) also play a big role.

As often happens when I read journal articles, this study led me to another published in 2010. Among more than 2500 teenagers from around Europe, Enrique Artero and colleagues found a significant correlation between how long they were breastfed as infants and how far they could long jump. Boys that were breastfed for 6 months or longer had an 11-cm edge over formula-fed boys, and girls had a 7-cm edge. On the other hand, there was no association between breastfeeding and speed in the 20-meter shuttle run. (That sure brings back memories from middle school!) Like the previous study, these data were adjusted for factors like the children’s physical activity and body composition and parental weight and education.

So breastfeeding my child means she’ll be better at both cycling and the long jump?!

Not so fast. You know I’m not going to report the results of new research without talking about its limitations. Both of these studies are retrospective, cross-sectional studies. They looked at kids that were breastfed and those that weren’t and compared their physical fitness. In an ideal world, if you wanted to know if breastfeeding was related to physical fitness later in life, you would enroll a bunch of pregnant women and assign them to either the breastfeeding group or the formula-feeding group. Then, 10-15 years later, you would run their kids through physical fitness tests. We all know that this type of prospective, randomized trial will never happen. No mother is going to let a researcher tell her how to feed her baby. Instead, each mother makes that choice herself, and there are many factors that contribute to her choice.

These types of retrospective, cross-sectional studies of breastfeeding always have one big flaw: they simply can’t account for every factor that may be different between breastfeeding and formula-feeding mothers. My guess is that the researchers have only scratched the surface by including maternal BMI and education in their statistical models. What about exercise during pregnancy? Or mom’s nutrition during pregnancy and lactation? How about exposure to cigarette smoke? These are all factors that might be different between breastfeeding and formula-feeding moms. Any of these factors, in addition to breastfeeding, might influence children’s later fitness level by epigenetic mechanisms or more directly, such as by affecting the rate and timing of muscle growth. Research on the benefits of breastfeeding is very hard to do.

As a skeptic and a scientist, I tend to think that this fitness effect is not just about breast milk but probably intertwined with other factors. But as a nursing mom, it is kind of cool to think about. I’ve tried to tell my daughter that the long jump may be in her future, given her 7 cm edge. She doesn’t seem to care. She has been practicing athletic feats during our recent nursing sessions, but they are more yogic in nature. I swear she did a one-legged downward dog the other day without breaking her latch!

References:

Artero EG, Ortega FB, Espana-Romero V, Labayen I, Huybrechts I, Papadaki A, Rodriguez G, Mauro B, Widhalm K, Kersting M, et al. 2010 Longer breastfeeding is associated with increased lower body explosive strength during adolescence. J Nutr 140 1989-1995.

Labayen I, Ruiz JR, Ortega FB, Loit HM, Harro J, Villa I, Veidebaum T & Sjostrom M 2012 Exclusive breastfeeding duration and cardiorespiratory fitness in children and adolescents. Am J Clin Nutr. Published online ahead of print 01/11/12.