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? 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

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

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

Does My Child Drink Too Much Milk?

glass of milk copyA couple of nights ago, I had the pleasure of going out for drinks with a couple of other moms, sans kids. Predictably, we ended up talking about our kids, among other things. One of my friends mentioned that her 2-year-old daughter is a big fan of cow’s milk, drinking about 3 cups per day. This reminded me of a study I’d gotten wind of earlier in the week that recommended kids drink only 2 cups of milk per day. Should my friend cut back on her daughter’s beverage of choice? I needed to look at the study more closely.

The study in question (The Relationship Between Cow’s Milk and Stores of Vitamin D and Iron in Early Childhood (1) – paywall) was conducted by a Toronto research group led by Jonathon Maguire and published on Monday in the journal Pediatrics.

The headlines about this study have made it sound like we now have the final word on just the right amount of cow’s milk for kids. The Atlantic posted a story with the headline “Kids Should Drink Exactly Two Cups of Milk per Day,” and others published similar statements. I will argue that it’s just not this simple, and prescriptive nutrition messages like these just end up confusing parents.

What is neat about this study is that it looked at two important nutrients for young kids: vitamin D and iron. Deficiency of both of these nutrients is common and cause for concern. Continue reading

Toddler-Approved Veggies: Roasted Beet and Broccoli Slaw

We’ll complete BabyC’s series of veggie recipes (see kale and carrots for more) this week with my favorite – a roasted beet and broccoli slaw.

This recipe comes from Alton Brown’s I’m Just Here for the Food. Like the carrot salad, it features grated veggies, and this presentation seems to appeal to my toddler. We’ve been inundated with beets around here. This salad turned out to be my favorite beet recipe this season. It calls for broccoli stems, which is awesome since I occasionally throw away the stems in favor of the prettier florets. The truth is that the broccoli in this salad is totally overwhelmed by the beets in both color and taste. That’s not a bad thing if you’re feeding kids that are suspicious of green color and bitter taste. The broccoli does add a nice crunch, and of course, great nutritional value. Continue reading

Toddler-Approved Veggies: Grated Carrot Salad

As promised, I’m sharing a few of BabyC’s current favorite veggie recipes this week. We talked kale chips on Monday, and today we’re on to carrots.

Karen Le Billon, author of French Kids Eat Everything, posted a French version of this grated carrot salad recipe on her blog a couple of weeks ago. I still haven’t gotten around to reading more than the first chapter (which she’s giving away for free on her blog and which I thought was fabulous) of her book, but I follow her blog with interest. If there’s one area that French parents really are superior to American parents, it is in how they feed their kids.

Here’s the quick version of Karen’s carrot salad recipe, but check out her page for more details:

Ingredients:

  • 8 large carrots
  • 2 tablespoons olive oil
  • Juice of one orange
  • Juice of half a lemon
  • One small bunch flat leaf parsley
  • Optional: a dash of Dijon mustard
  • Pinch of salt

Instructions:

  1. Mix dressing by combining olive oil, juices, mustard, and salt.
  2. Grate carrots as finely as possible.
  3. Mince parsley.
  4. Mix carrots, dressing, and parsley. Serve slightly chilled or at room temperature.

I did not pay close enough attention to Karen’s directions when I made this, and I just used the regular large grate side of my box grater for the carrots. Karen says that the salad is best when the carrots are grated very finely, so I will try a smaller grate next time around. Regardless, BabyC loved this salad and ate it by the handful.

I have also had good luck with grated carrots mixed with raisins, sunflower seeds, and whatever prepared vinaigrette I have in the fridge.

While we’re talking French food, I have learned a few other good tips from Karen’s blog: Continue reading

Toddler Approved Veggies: Roasted Kale Chips

After months of great skepticism of vegetables, particularly those that are green, BabyC has recently started to be a little more adventurous at mealtime. I think there are a few things going on. For one, we’re getting lots of fresh-from-the-farm veggies from our CSA, and fresh veggies really do taste better. I also think that our no-pressure, child-led yet adult-structured attitude about toddler feeding is starting to pay off. Finally, BabyC may be going through a growth spurt, as she just seems more interested in food in general these days.

I try to be laid-back at mealtime and let BabyC decide what and how much to eat from the food on the table. Still, when she chooses veggies and eats them enthusiastically, it is hard to keep my heart from swelling with pride just a little. This week, I’m going to share 3 veggie recipes that BabyC has been eating with gusto, starting with the biggest hit of all:

Roasted Kale Chips

I know that kale chips have been all the rage of the food blogosphere for a few years now, but I had to include them here. This is pretty much the only way that I’ve seen BabyC eat dark leafy greens, and Husband and I love them, too. If you haven’t tried kale chips yet, now is the time.

Yes, that is my child crying out for kale chips. And yes, I love this photo.

I’ve tested a few kale chips recipes from around the Internet to come up with my own fool-proof method. Continue reading

BabyC’s 12 Steps to Healthy Toddler Eating

I used to think I knew a lot about food. I have a Ph.D. in Nutrition, for crying out loud. Then I became a mom.

It isn’t just about me anymore. As a mother, I feel the weight of the responsibility of raising a healthy eater. I want BabyC to not only eat well today, but to also enjoy eating and grow up to have a healthy relationship with food. None of my coursework in grad school prepared me for this job.

Over the last year, I have learned a lot about feeding a child. Who has been my most important teacher? The kid herself.

If BabyC could say more than “ack-ack” (cracker) or “ana” (banana), here’s what I think she’d like me to know about feeding her:

Lesson 1. You can’t make me eat anything. You just can’t. You can try, but Mama, that just takes the fun out of it! And how do you think I’ll feel about broccoli in 20 years if you force me to eat it now?

Lesson 2. Relax. It isn’t your job to decide how much or even whether I eat. That’s my job. Your job is to fix good food and put it on the table at regular mealtimes. You can handle that, right?

Lesson 3. Sit down to eat with me. Otherwise, I feel bored and will take the opportunity to repeat my milk pouring experiment for the 248th time. I feel pretty certain about the gravity thing, but now I’m curious to see just how large of a diameter I can make it splatter on the floor. Continue reading

A Toddler and Her Food: An Evolving Relationship

A reader emailed me the other day asking for an update on BabyC and her relationship with food. In the early days of the blog, I wrote quite a bit about feeding and nutrition, but lately I’ve been distracted by other topics. My next couple posts will revisit food in our family, including some lessons I’ve learned on feeding a toddler. Let’s start with a recap of the story of BabyC and Food.

Chapter 1: Milk Monogamy

These were the days when BabyC was a one-food girl. Feeding was simple and sweet. While we technically breastfed on demand, in practice BabyC and I fell into fairly predictable routines, and after the first couple of months, it didn’t feel demanding at all. She ate when she was hungry and stopped when she was full. She knew that she could count on her next meal being there when needed, so there was no need to worry beyond that. BabyC was exclusively breastfed until she was around 5 months old, but breast milk provided at least 90% of her calories until she was around 8 months old.

{I know what you’re thinking: “Alice! Don’t you know you’re supposed to wait until 6 months to start solid foods?!” At the time, I wasn’t convinced that there was strong evidence for waiting. BabyC had been falling off the WHO growth charts, and I figured it wouldn’t hurt to get a jump-start on solid foods. Plus, she was grabbing at the food on my plate, and I was excited to introduce her to the tastes of the world. These days, I think that there is sufficient evidence to recommend waiting until 6 months to introduce exclusively breastfed babies to solids. However, as with most recommendations of this sort, I also think there is some wiggle room depending on the baby’s development and desires.}

Chapter 2: A Skeptical Introduction

Anyway, we started dabbling in solid foods around 5 months. Rice cereal was a non-starter, and we quickly moved on to more interesting foods: banana, carrots, sweet potato, and avocado. I offered little flirtatious bites to BabyC. They were colorful and often accompanied by a song. She would usually entertain them with a small taste and then turn up her nose at the rest.

Chapter 3: Head Over Heels

BabyC’s skepticism about food continued until we took her on vacation to Hawaii when she was about 7 months old. I think this was a turning point because I relaxed about the whole thing. We were on Island Time. I stopped trying so hard and just started giving BabyC pieces of good food when we were enjoying it: A bit of French bread as we waited for our dinner at a restaurant, a chunk of super-ripe mango, a spoonful of soft papaya, a bite of my banana.

Suddenly BabyC was enthusiastic about foods. She wanted to try them all! She just wanted finger foods, please. She wanted to control how much and how fast she ate. Surely that wasn’t too much to ask? Continue reading