Amylase in Infancy: Can Babies Digest Starch?

Several readers have emailed me to ask about babies’ ability to digest starch. Here’s one:

“I have noticed you recommending cereals for babies several times.  I am sure that you are aware that many people look at feeding a baby grains before the age of one or even two as if you have offered your child strychnine. One of the reasons cited is that they supposedly do not have amylase to digest grains before that time. I have often wondered what exactly is happening to the cereal if it is not being digested, but the only statement I could find is something about it “rotting” in the gut.

I would love to get information from a scientific point of view on this topic.  Everything I have been able to find thus far has been very biased towards one point of view or another. Either “cereal is the perfect first food. Easy to digest and enriched with iron” from the infant cereal companies or “Cereal is junk.  No infant should ever eat grains. It is not natural or traditional and they can’t digest it” from online parenting sites.

I need a little clarity and common sense.”

~Hope

I love the skepticism in Hope’s email, and I can also empathize with her frustration about how difficult it is to find good information about a seemingly simple question: Can babies digest starch? If you search for the answer to this question online, you will run into dire warnings of the dangers of giving starch to babies. But these sites might set off your woo detector – as they should. So, after receiving multiple emails about this question as well as seeing it mentioned in discussions on the Science of Mom Facebook page, I figured it was time to put some evidence-based information about babies and starch digestion on the Internet.

Researching this question has given me an excuse to read some classic nutrition physiology papers harkening back to the 1960’s and 1970’s, and it’s brought back memories of years in the lab, exploring nutrient digestion and metabolism. And starch digestion in infancy, it turns out, is a really neat story.

Let’s start with some basics about carbohydrate digestion.

What is starch? How is it digested?

Starch is a type of complex carbohydrate. Made from lots of glucose molecules bonded together in long, branching chains, it is a plant’s way of storing glucose – product of photosynthesis and source of energy – in a stable form. We find starch in grains, root vegetables, winter squashes, beans, and some fruits, like bananas. Starch is an important storage depot for the plant, and it also makes for tasty staple foods for cultures around the world.

One little section of starch, containing 3 glucose molecules. Wikimedia Commons, public domain.

A chain of 3 glucose molecules, like a tiny section of starch.

Glucose is the major fuel for the cells of the body. When we eat starch, we have to break the bonds in those chains of glucose molecules, liberating them to be absorbed from the small intestine into our blood. Starch digestion begins in the mouth, where salivary amylase starts chopping up those large glucose chains. When this partially digested starch gets to the small intestine, amylase made and secreted by the pancreas jumps in to do more bond-breaking and is responsible for most of starch digestion in adults. A suite of enzymes produced by the cells lining the small intestine, including sucrase, isomaltase, maltase, and glucoamylase, work on the remaining short chains, finishing up the job and making glucose available for absorption.

Starch Digestion in Infants

Infants go through some incredible nutritional transitions in the first months of life. Prior to birth, their growth and development is fueled almost entirely by glucose from mom, absorbed across the placenta. After birth, they have to abruptly transition to an exclusive milk diet, which is high in fat and lactose, still a relatively simple sugar. As they start solid foods, babies have to adapt to a much more complex and varied diet. Around the world, starch is a major source of energy in the diets of children and adults alike. But when infants are first introduced to starchy foods – often in the form of cereals and porridges – starch is a novel nutrient to their digestive tract. They need to turn it into glucose, but are they equipped to do this?

It’s true that infants have low levels of pancreatic amylase, the workhorse of starch digestion in adults. Research in the 1960’s and 1970’s showed that pancreatic amylase activity, measured in samples of fluid from the small intestine, is almost non-existent in newborns. Activity starts to increase within the first six months, however, and continues ramping up throughout childhood. By four to six months, when many babies are introduced to starch in the form of cereals, there is some pancreatic amylase activity, but still much less than that found in older children and adults.

Looking at these results, scientists questioned whether babies could handle starch very well. But they didn’t throw up their hands and declare, “No starch for babies!” They kept asking questions and seeking answers. They must have been puzzled by the fact that babies appeared to digest starch just fine. For example, think of the experience of those who are deficient in another carbohydrate-digesting enzyme, lactase, which allows us to digest lactose, the carbohydrate in milk. What happens if they drink a glass of milk? They have obvious, uncomfortable symptoms of diarrhea, nausea, cramping, bloating, and gas. These symptoms weren’t apparent in young babies eating infant cereals, which in the U.S. in the 1970’s, were usually introduced to babies by 1-2 months of age. My mother-in-law recorded my husband’s first teaspoon of doctor-recommended rice cereal in his baby book at 4 weeks, yet her careful records didn’t include any concerns about a sudden onset of diarrhea.

Baby book, ca. 1975

Baby book, ca. 1975

And this approach to infant feeding wasn’t that unique to the U.S. Ethnographic reports are filled with examples of starchy first foods for young infants around the world: Millet flour at 3 months in Tanzania; corn porridge at 3 months in Zimbabwe; beans and rice at 4 months in Brazil; a little butter and flour at 3 days in Bhutan; rice mash at 3 weeks in Nepal; and prechewed taro root at 2 weeks in the Solomon Islands. If babies were eating starch this young, with no apparent clinical signs of malabsorption, there must be more to the story.

The studies of pancreatic amylase activity had only measured its activity in a test tube in the lab. Next, researchers took a more holistic approach and measured starch digestion in the babies themselves. A 1975 Italian study added starch from different sources (potato, tapioca, corn, wheat, and rice) to 1-3-month-old babies’ formulas and then checked to see what came out at the other end –- in the babies’ poop. It turned out that very little starch ended up in these babies’ diapers. When they were given between 1 tablespoon and ½ of a cup of starch per day, they appeared to digest more than 99% of it. The researchers then tried a larger dose, giving several 1-month-olds a full cup of rice starch. Three of these infants absorbed more than 99% of this amount. Two absorbed just 96%, the other 4% ending up in their diapers, along with some diarrhea. In other words, within the first few months of life, babies can digest small amounts of starch just fine, but give them too much and you’ll see some diarrhea. (And no, I’m not suggesting that we feed 1-month-olds cereal – this was just the research at the time.)

How is this digestion of starch possible if babies have so little pancreatic amylase at work?

There are probably several mechanisms at play:

1. Babies make lots of salivary amylase. Although newborns secrete little salivary amylase, production increases quickly in the first few months after birth [PDF], reaching near adult levels by 6 months of age. Salivary amylase appears to survive the acidic conditions of the stomach reasonably well and is protected by both the presence of starch and breast milk. Once it is dumped into the small intestine, where pH is more neutral, it resumes its work of breaking down starch.

2. Human breast milk has lots of amylase, 25x that found in raw cow’s milk. Interestingly, it is highest in colostrum, and decreases slowly during infancy, as salivary and pancreatic amylases are increasing. Like salivary amylase, breast milk amylase retains at least 50% of its activity even after several hours of exposure to the low pH of an infant’s stomach, passing into the small intestine ready to get to work. It also seems to be protected by proteins in breast milk. One researcher estimated that the amylase in 100 ml of breast milk was capable of digesting 20 grams of starch (equivalent to 2/3 cup of dry rice cereal) in one hour. This is one good reason to use breast milk to make up cereals for young babies, and studies show that amylase is stable in breast milk for hours even after repeated freezing and thawing.

3. Glucoamylase helps out in the small intestine. Glucoamylase is an enzyme made by the cells lining the walls of the small intestine. Like amylase, it breaks the bonds between glucose molecules in starch and shorter glucose chains. But unlike pancreatic amylase, glucoamylase is very active in infants, reaching adult levels as early as 1 month of age.

All of these sources of starch-digesting enzymes – salivary and breast milk amylase, as well as glucoamylase in the small intestine – appear to work together to help babies digest starch to glucose. But that isn’t the end of the story.

Studies have shown that a significant fraction of dietary starch isn’t digested in the small intestine of babies but passes on to the large intestine. Is this where it “rots” in the gut, as the alarmist blog posts claim? Not so fast. Bacteria in the colon ferment (quite a different process from rotting) these undigested carbohydrates as part of the healthy symbiotic relationship between our gut microbes and us humans. It happens in adults, too. Even with their full activity of pancreatic amylase, some starch escapes digestion in the small intestine, as does dietary fiber. These undigested foods help feed the microbes, who kindly benefit us in lots of ways. The end products of microbial fermentation in the colon are short chain fatty acids, which can improve nutrient absorption, enhance gut health, and even be used as a source of energy for both the microbes and the human host. Babies and toddlers may actually have faster colonic fermentation of starch than adults, which might represent an important pathway for them to fully capture the nutrients in their food. The addition of complex carbohydrates, including starch and fiber, to the diet of older babies and toddlers might help to develop those healthy microbes.

OK, so maybe babies can handle starch just fine. But is there any harm in waiting a year or two to introduce it, just in case?

I can think of a few reasons why we should be careful about limiting starch in a baby’s diet:

1. Waiting too long to introduce grains to your baby could end up increasing the risk of developing celiac disease, Type 1 diabetes, and wheat allergy. There seems to be a sweet spot kind of window in mid-infancy – probably between about 5 and 7 months, where introduction to a variety of foods, including grains, decreases baby’s risk of developing chronic disease and allergies later in life.

2. Eliminating starch can make it more difficult for babies to get the nutrients they need. Infant cereals are fortified with iron, one of the nutrients most likely to be limiting to infants, even in the developed world. They are stable for long-term storage, and it’s convenient to mix up just a tablespoon of cereal at a time. You can certainly meet the nutrient needs of babies without cereals, but it takes more work and experimentation. When Cee was a baby, she was not at all interested in eating fortified baby cereals, and I found other sources of iron for her. But if your baby likes cereals, I wouldn’t hesitate to include them as one of a variety of foods in his diet. Also, this concern about starch digestion and amylase tends to be focused on avoiding grains, but remember that legumes and many fruits and vegetables also have lots of starch. If you truly tried to avoid starch, you would really be limiting your baby’s opportunities to gain nutrients and experience with different tastes and textures.

By Keith Weller, USDA ARS [Public domain or Public domain], via Wikimedia Commons

3. There may be negative consequences to being anxious and restrictive about food with young children. We seem to have an ongoing obsession with restrictive diets. It used to be all about restricting fat, then all carbohydrates, and now grains are getting a bad rap. I don’t think this is healthy. Barring allergies or intolerances, eating a variety of foods from all the food groups pretty much ensures that you’ll meet your nutrient requirements without even trying. It allows you to relax and enjoy your food with the people you love, which is really what eating should be about. When you start eliminating food groups, you increase your risk of nutrient deficiencies, increase anxiety about food, and make it more difficult to share food. It’s one thing to make this choice as adults, but in my opinion, to impose it unnecessarily on our kids isn’t fair. When a two-year-old isn’t allowed to have a cupcake at a birthday party, he might feel different and deprived, and he’s lost a chance to practice eating treats in moderation. Parents of kids with food allergies have to work carefully to manage these situations, but for the rest of us, this kind of restriction is unnecessary.

The bottom line is that it is safe to feed babies starchy foods. They can digest them, and they are one part of a varied, balanced diet for babies that are ready to begin eating solid foods. I’ll be writing more about the transition to solid foods in the next few weeks.

What information did you get about introducing grains and other starchy foods to your baby? What did you actually do?

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

What’s Your Feeding Style? (Fearless Feeding Review and Giveaway)

Do you have a feeding philosophy? What’s your feeding style?

These are not the most common topics in parenting discussions. We’re often too busy talking breast and bottle, baby led weaning or purees, organic or conventional, and how to get our kids to eat more vegetables. But the question of feeding style, I believe, matters more to children than any of these oft-discussed topics.

I am really pleased to have a new book on my shelf that covers the HOW and WHY of feeding children just as well as it covers WHAT to feed: Fearless Feeding: How to Raise Healthy Eaters from High Chair to High School, by Jill Castle and Maryann Jacobsen. Both authors are registered dieticians, mothers, and bloggers. They take a long-term view on feeding – that we shouldn’t just be concerned with what our kids are eating today, but also about teaching kids to eat well for a lifetime.

9781118308592_Castle.inddFeeding style is one of the first topics in Fearless Feeding, so if you’re not sure how to describe your own feeding style, here’s your chance to give it some thought. Castle and Jacobsen discuss 4 feeding styles, analogous to parenting styles that may be familiar to you: Continue reading

SIDS and Bedsharing: A Pediatrician’s Perspective

I’ve been thinking about bedsharing and sleep safety for the last few months. I have devoted an entire chapter of my book to this topic. Not only is it an important question for parents, but it’s an issue with so much complexity — wrinkles and folds of factors like breastfeeding, bonding, instinct, culture, and just plain reality.

I think it is vitally important to understand the relationship between bedsharing behavior and risk of SIDS and accidental deaths. But our ability to tease apart every factor that might impact sleep safety is imperfect; there will always be factors that aren’t quantified in these studies, not to mention the fact that case control studies have some inherent limitations. You’ve probably heard about the study published this week by Carpenter et al. in BMJ. It combines 5 historic case control data sets from Europe, the U.K., and Australasia to specifically look at the risk of bedsharing in breastfed babies in nonsmoking households. It concludes that bedsharing poses an increased risk of SIDS, even in these ideal situations. I think it’s an important study, but it also has some limitations and doesn’t answer all of our questions with certainty. In fact, no study will probably ever do that. (You can read some critiques of the Carpenter study here and here.)

But even if we accept that bedsharing increases a baby’s risk of dying unexpectedly during sleep, we still have to answer the bigger question of how we translate this information to families living in the real, difficult world of infant sleep. Many families value bedsharing as a cultural practice; others choose it because it feels right. Still others bedshare because it is the only way that anyone gets any sleep at night, and we all know that sleep deprivation carries some risk, too, as does falling asleep on a couch with your baby. This is the reality.

Pediatricians face this reality in their clinics every day, when they talk with parents of new babies about sleep. In my book, one of the questions I explore is how pediatricians handle this conversation, given that their professional organization, the American Academy of Pediatrics, recommends against bedsharing. Several months ago, I sent some questions to one of my favorite pediatrician bloggers, Dr. Melissa Arca of Confessions of a Dr. Mom. She had initially agreed to a Q&A, but then she didn’t respond with her answers. It was the height of the busy flu season, and I figured that she was just busy. Then, this week, she surprised me with her responses. She had been thinking about bedsharing given the news of this recent study, and she was inspired to restart this conversation. We’ve cross-posted our Q&A on both our blogs. Check out her post for more about her initial hesitancy to address these questions, and please feel free to share your experiences in the comments below.

Alice: How did sleep look for your two children?

Melissa: My first child was a challenge to say the least. He is the one who made me question the safety of bed-sharing in the first place. For the first 6 months of his life, sleep was virtually non-existent (or at least that’s the way it felt to me) because he needed my arms and constant soothing throughout the night. But I was terrified to bedshare. I was literally at the end of my sleep deprivation rope. I had tried everything. And instead of listening to my instincts, I was fighting them. Because I was scared.

I never envisioned myself as a bedsharing parent. As a pediatrician, I was adamantly against it. But it was exactly what my baby needed and we struggled and limped along until I finally realized that.

My second child was a breeze and that’s no lie. She was always (and still is) an “easy sleeper”. She needed her space and showed clear signs of being tired. When she was tired, that was it. I didn’t need to bedshare with her. She slept in her own bassinet next to our bed during her first few months of life before being transitioned to her own room.

They could not have been more different in the sleep department. Same parents. Same environment. Different children.

Alice: As a pediatrician, how did you feel about bedsharing before having children? Did becoming a mother change that?

Melissa: I didn’t think it was safe. At all. I had read the studies and the official recommendations. Back to sleep, crib and/or bassinet in the same room with no hazards such as loose bedding, pillows, etc.

I never thought in a million years I would have become a bedsharing parent. But kids don’t have our same agendas. Continue reading

Baby Meets World: A Conversation with the Author

Yesterday, I posted an excerpt from Nicholas Day’s new book, Baby Meets World. If you missed it, check it out to learn how modern hunter-gatherer societies raise children, and how that task is supported by not just by hard-working mothers but the entire culture. It’s good stuff.

After reading his book, I had lots of questions for author Nicholas Day. Today, I bring you our conversation about his book and on the roles of science, culture, and instinct in parenting.

Alice: Becoming a parent changes all of us. What was it about your particular transition to fatherhood that made you want to research and write this book, to dive into the history and the science of parenting in a way that extended beyond your own reality of parenting?

IMG_4413Nicholas: In a way, I think it was the part of me that wasn’t changed that led to this book: I had stupid questions about babies in the same way I have stupid questions about everything else. (It’s a personality flaw.) I didn’t see why I had to think of babies as simply problems to be solved. Most baby books have what I think of as the leaky faucet approach: if your baby is dripping, we recommend this socket wrench. And there were many, many times when all I wanted was that socket wrench. But I also thought babies were interesting subjects all on their own. I wanted a book that acknowledged that. And I wanted a book that was wide-angled. The study of infancy is highly compartmentalized: the different disciplines don’t talk to each other. The few good books about babies tend to be highly focused: they look at babies through the lens of a cognitive scientist, say, or a developmental psychologist. But there are so many lenses out there! It seemed a shame to only see a baby as like this or like that. There’s so much left outside the frame. So this book tries to show readers the many different versions of a baby that people have seen—and still see today.

It’s strange. You wouldn’t think that babies would be an obscure subject: they are everywhere. (In our highly fertile neighborhood, I sometimes feel like Hitchcock’s The Birds is being reenacted—but this time with babies.)  But they’ve been weirdly neglected. This is sort of hard to believe: any book about babies has to clear the high hurdle of being another damn book about babies. (Right? Like that’s what we need. Also, we totally need more diet books.) But I concluded that we really did need that. Babies are still strangers in our midst.

Alice: Your book focuses on four basic facts of infancy: “suck, smile, touch, toddle.” How did you choose these topics? Why not “eat, sleep, poop, cry,” for example?

Nicholas: I joke about this at the end of the book—that there’s so much going on in infancy I could easily have chosen spitting, shitting, screaming, sharing.

Part of why I went with these topics was that I actually wanted answers about them: I really wanted to know where a smile comes from and what a first smile might mean, for example. But I also thought these subjects had been overlooked. There’s been an enormous amount written on sleep, for very obvious reasons: any new parent is obsessed with sleep. But there’s very little written about smiling or walking. It’s the leaky faucet problem: because a smile can’t be fixed, no one writes about it. Continue reading

Sleep Deprivation: The Dark Side of Parenting

Sleep deprivation is an inevitable part of having a baby, and surely that’s been true throughout the history of our species. But we also live in a culture that seems to take some amount of pride in getting by on little sleep. We think of sleep as time wasted, as lost productivity. We forget – or ignore – the biological necessity of sleep.

Becoming a parent only further stretches our already-too-thin sleep allotments. Newborn babies wake frequently to feed or for comfort during the night. We try to “sleep when the baby sleeps” and piece it together to come up with a reasonable amount, but it often doesn’t feel sufficient. And now more than ever, new parents are really isolated as they make this transition; they don’t have much in the way of backup resources to help with the 24/7 job of caring for a baby.

This month, the theme of our Carnival of Evidence-Based Parenting is Transition to Parenthood. (See the bottom of this post for links to other Carnival posts and here for summaries of them all.) Sleep deprivation is a universal part of that transition. What does the sleep deprivation of early parenthood really look like? How does it affect us? And what can we do to mitigate it?

Just How Bad Is It?

For many moms, sleep debt actually begins in pregnancy, when sleep needs may increase but discomfort and frequent trips to the bathroom interfere with a full night’s sleep. But by far, the biggest change happens in the immediate postpartum period. One study found that in the first week of the baby’s life (compared with late pregnancy), moms got 1.5 hours less sleep, fragmented into three times more sleep episodes per day. The early postpartum period is also characterized by lots of day-to-day variability in sleep. Sleeping with a new baby means unpredictability, with little to no control over whether tonight will be a good night or a bad one.

Mothers usually get the majority of our sympathy when it comes to postpartum sleep deprivation, but the research shows that fathers’ sleep takes a hit, too. A study of 72 San Francisco couples welcoming their first baby compared sleep in the last month of pregnancy to sleep in the first month postpartum (around 20 days of life).  Across this time span, mothers lost an average of 41 minutes of nighttime sleep, while dads lost just 18 minutes. Moms, however, gained 30 minutes per day in daytime napping; dads didn’t get a nap bump at all. In fact, in this study, dads actually slept less than moms – both in late pregnancy and in the postpartum period. Moms still had it harder; they were waking more during the night and had more sleep fragmentation than dads (and it’s quite possible that moms need more sleep, what with recovery from childbirth and the demands of breastfeeding). But regardless, in this and other studies, moms and dads both reported a similar level of fatigue during the day.

There’s some good news to come out of this research, however. It seems that experienced moms are better at handling sleep in the postpartum period. Despite juggling more responsibility at home, studies show that moms who had given birth at least once before tended to get more sleep at all stages of pregnancy and in the postpartum period. Their sleep was also more efficient, meaning that of the time they spend in bed, they spend most of it sleeping rather than tossing and turning – or laying awake listening to the grunts and sighs of new baby sleep. Somehow, experienced moms seem to prioritize sleep more, or they’re just so tired that they crash hard at every opportunity.

How does sleep deprivation affect new parents?

We know a lot about the effects of sleep deprivation but actually very little about the specific type of crap sleep experienced by new parents. Most sleep deprivation studies have been conducted in residential labs, where participants (often young, probably resilient, undergrads) are generally paid to live for a few nights or maybe weeks so that their sleep habits can be controlled and monitored. In a review paper entitled “Sleep Disruption and Decline in Marital Satisfaction Across the Transition to Parenthood,” Gonzaga professor Anna Marie Medina and colleagues make an important point: Lab study participants know that they’ll be subjected to sleep deprivation for a finite amount of time, and they know they can even drop out if it becomes too much for them.

“Understanding that one can end a study, and being certain of the temporal parameters of potential sleep deprivation, imbues the experience of sleep loss with a level of controllability that new parents seldom have. That is, (most) new parents realize they cannot opt out of the sleep disruption experience, and they have no certainty about when they may have an opportunity for sufficient sleep. The stress literature has suggested that such uncontrollability could amplify the mood and physiological consequences of sleep deprivation.”

In other words, most of what we know about the effects of lost sleep may be even worse in new parents. On that happy note, there are a few major areas of concern… 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

Rocking and Swinging Babies to Sleep, In Thailand and the Rest of the World

I’m working on the “sleep strategies” chapter of my book. This chapter is about the strategies that we use to help our babies sleep and how these practices correlate to the development of baby’s sleep patterns.

I’m fascinated by cultural variation in nighttime parenting strategies. However, according to some accounts, there’s a simplistic dichotomy in the way parents around the world help their babies sleep. In most of the world, mothers sleep with their babies and breastfeed on demand throughout the night. Sleep is not a problem, because babies simply aren’t expected to sleep through the night. We in the West, however, don’t understand normal infant sleep. We bend over backwards with all sorts of tricks and gadgets to help our newborns sleep, often alone. (I’m looking at you, swings, bouncy seats, strollers, drives in the car, exercise balls, washing machines.) Then, a few months later, we tire of the antics, grow intolerant of night wakings, and turn to sleep training as the answer.

There is definitely some truth to this. It’s something that I’m writing about in greater detail in my book. But we also know that nothing is as simple as it seems, and infant sleep is no exception. I think it’s helpful to know that parents everywhere struggle with their babies’ sleep or lack thereof, and that’s true regardless of sleep customs or cultural expectations (Sadeh et al. 2011). No matter where they’re born, babies have to acclimate to a world that grows dark and quiet at night and bright and busy during the day. We might use different strategies to help our babies sleep, but there are many similarities as well.

I ran across one of these similarities in a paper I read yesterday (Anuntaseree et al. 2008). Thai researchers surveyed parents of three-month-olds born across the country in 2000. They asked the parents how their babies fell asleep, where they slept, how they were fed, and how often they woke during the night. The parents of more than 3700 babies responded to the survey.

Most of these babies – 68% – shared a bed with their parents. The rest slept in a separate bed but in the same room. Putting babies to sleep in a separate room was nearly unheard of. Of 3700 babies, only two slept alone (a whopping 0.05%). About half were exclusively breastfed, and another quarter were fed a combination of breast milk and formula. On average, these three-month-old babies woke their parents 2.7 times per night, but there was of course a lot of variation here. Nearly 50% woke just one or two times per night. The researchers wondered which factors were related to waking more often, and they found significant correlations with these: male gender, more than three naps per day, falling asleep while feeding, exclusive breastfeeding, and the use of a swinging or rocking cradle.

The gender and napping associations are a little odd and not supported by other studies. However, the rest of it isn’t surprising. It is well accepted that breastfed infants wake more often during the night. Human breast milk is more rapidly digestible than formula (Cavell 1981), so breastfed babies need to feed more frequently. It’s also a common finding that feeding to sleep increases waking (or more accurately, waking the mother) during the night.

But I was really interested in learning more about the swinging or rocking cradles mentioned in this paper. It turned out that 88% of babies commonly started their night in such a cradle. Here’s how the paper described it:

“Use of a swinging or rocking cradle for infant sleep is traditionally used in many Asian countries including Thailand. The typical “getting the infant to sleep” situation in Thailand is for parents to use a cradle as a sleeping aid, and then when the infant falls [to] sleep, transfer the infant to the bed. There has been no previous study regarding the effect of this custom on night waking; our study is the first to demonstrate this association.”

 

I was curious about what a Thai swinging cradle might look like, so of course, I Googled it. The only photos I found showed a pretty extraordinary contraption: Continue reading