From Medscape Pediatrics
Starting Solid Foods: Are We Doing It Right?
An Expert Interview With Alan Greene, MD
Editor’s Note: The epidemic of overweight and obesity in American children is no longer news. Countless hours of research have been devoted to examining the impact of obesity on a child’s health and numerous treatment options have been explored. While many management strategies have been found to have variable effect in different populations of children, it is clear that there is no single methodology and that the most effective intervention is to prevent overweight in the first place. Prevention, too, is not a simple process and also requires an individualized approach.
Medscape spoke with Alan Greene, MD, a pediatrician at Stanford University’s Lucile Packard Children’s Hospital and author of Feeding Baby Green and www.DrGreene.com, about the state of current research on obesity prevention in infants and children and his own current initiatives on this subject.
Best Practices for Infant Feeding
Medscape: Dr. Greene, it is clear that among the myriad health benefits attributed to breast feeding in infancy is a favorable effect on weight gain. Can you summarize some of these data?
Dr. Greene: The more we learn about breastfeeding, the more we learn about how powerful it is for babies in a variety of different ways. The immune benefits are incomparable, the nutrition benefits are incomparable, the taste benefits are incomparable. Breast milk tastes different every single feeding, which exposes the baby to a variety of flavors, and studies have shown that what a nursing mother eats can help predispose her child to learn to like later.
The breastfeeding and obesity question is one that has been highly controversial. It is biologically plausible that breastfeeding could have a powerful programming effect in preventing overweight or obesity. We know that there are significantly higher plasma insulin concentrations in infants who are bottle-fed compared with those who are breastfed, which would be expected to change fat deposition and development of fat cells.
We also know that breast milk contains biologic factors that can inhibit adipocyte differentiation in vitro. The amount of calories metabolized and the protein intake of breastfed kids is considerably lower than in infants who have been formula-raised. In controlled prospective studies, that lower protein content accumulated in breast milk has been demonstrated to be associated with lower likelihood of obesity. So there are lots of reasons to think that breast milk would, in fact, be protective.
However, around the beginning of the 21st century, there were a number of observational studies examining breastfeeding and later obesity or overweight. While some of them showed a protective effect, a number of them were unable to demonstrate a statistically significant effect, which has led to a lot of controversy in the area. Most recently, there was an excellent review article that appeared in the April 27, 2011 online version of theAmerican Journal of Clinical Nutrition that looked at breastfeeding vs formula feeding. The researchers hypothesized that the reasons for the disparate outcomes in previous studies may have been because the positive effect of breastfeeding on weight may be confined to only those children at the higher end of the body mass index (BMI) curve. To examine this possibility, they looked at data from over 14,000 children ranging in age from 54 to 88 months who received a school health examination in Germany between 1999 and 2000. Their analysis controlled for a number of potential influences of weight including sex, age, television viewing, maternal BMI, parental education, maternal smoking during pregnancy, and early weight gain. What they found was that the protective effect of breastfeeding was indeed confined to children between the 90th and 97th percentile with a reduction in BMI of -0.23 and -0.26, respectively. So, not all of the questions have been answered yet. It is not conclusively proven but it is biologically plausible, with several large meta-analyses and this most current paper showing an effect. It is yet another good reason to recommend breastfeeding to families.
Medscape: The Healthy People 2020 target for the proportion of mothers who ever breastfeed their babies is 81% with specific goals of 60% at 6 months and 34% at 1 year. How are we doing in meeting those goals? Are there particular women to whom we should devote increased attention?
Dr. Greene: We are not at those goals yet by a considerable stretch, but there is good reason to believe that we can meet those goals by 2020. Right now, about 75% of women are breastfeeding ever. Back in 2000, only about 70% of women were breastfeeding ever. A similar increase over the rest of this decade is certainly achievable.
The goal for percentage of women still breastfeeding at 6 months is 60%. Right now, we are only at about 43%. In 2000, we were only at 34%, so if we can keep our momentum going, we should be able to get there.
Finally, our goal is to have 34% of women doing at least some breastfeeding at a year. Right now, only 22% of women are nursing at their infant’s first birthday but only 15% were doing so back in 2000. So again, reasonably, we can meet those goals.
There are 2 groups of women on whom to particularly focus attention. The first are working women. About half the American workforce is women. Returning to work can be a big obstacle to continued nursing. Balancing that struggle of working and breastfeeding is difficult and only about a quarter of employers provide onsite support or even just a room for women who want to nurse. Making the workplace favorable for breastfeeding is a huge issue that must be dealt with.
The other group that should receive attention is brand new mothers in the immediate postpartum period. Right now, about 4% of babies in the United States are born in hospitals that are designated baby-friendly and encourage exclusive breastfeeding at the beginning of life. Almost a quarter of breastfed babies receive formula within the first 2 days of life. If we can teach new mothers what to expect and how breastfeeding works in the first critical days after delivery, I think we can go a long way towards meeting those goals.
Medscape: A number of other factors are recognized to be important in the development of feeding preferences and practices in infants and toddlers, including timing of first solids, types of solids, and even the rapidity with which a child ingests these foods. Can you describe some of the most important of these studies and their implications for parent education?
Dr. Greene: A very important study from the Division of Gastroenterology and Nutrition at Children’s Hospital Boston was published in February 2011. The researchers examined the timing of solid food introduction and the risk for obesity in preschoolers by following 847 children prospectively. The formula-fed, though not the breast-fed, children who were introduced to solids before 4 months of age were 6 times more likely to end up obese at 3 years old. The researchers speculated that these children actually increased their energy intake as a result of the inclusion of solid foods. It appeared to change the amount that they ate and the way their body dealt with calories later on, an example of metabolic and possibly flavor programming.
Another interesting area of research has examined the impact of early taste exposures on lasting taste preferences. We are all familiar with the baby food window, the time that they are putting everything they can find into their mouth. It appears that children who sample a vegetable or a fruit on average 6-10 times have a high likelihood of developing a preference for that food.[6.7]
Unfortunately, the Feeding of Infants and Toddlers Study (FITS), which was an examination of feeding habits, found that in the 21st century 94% of parents give up on feeding a new vegetable by 5 times or fewer. Parents appear to decide the baby is not going to learn to like it. Only 1 or 2 parents in 100 will try it a full 10 times. So one of the things that we can do to teach good nutrition habits is to encourage parents to provide a variety of flavors and do it multiple times in a relaxed positive environment. In a study published in 2007, researchers asked parents what was their child’s least favorite vegetable and then asked them to give their baby just a bite of that food as the first bite of solids in a particular meal, without forcing the child to consume it, and to do that every day for a week. At the end of the week, 85% of those kids who hated that vegetable had come to really enjoy it. Some 70% of them still liked it a year later when they were in the picky meal phobia stage where toddlers have a built-in fear of new foods and new sources of foods.
In the last year, there have been a couple of interesting studies looking at the pace of feeding in older children. One of these was a study that looked at the feeding behaviors of 4-year-olds. The researchers placed a big buffet in front of these children and observed them eating at length. They looked at which foods they chose, whether it was high calorie, junk food, or dessert. The researchers also looked at the messages the parents provided to the children to "eat more of this" or "don’t eat more of that." The study also examined how quickly the children ate. In short, every different aspect of the child’s eating behavior over the course of this buffet was examined and recorded.
The children returned a couple of years later to see which ones had become obese. The original data were re-examined to see if there was something about these children’s eating habits at age 4 years that might have been predictive. What the authors found, surprisingly, was it was not the total number of calories consumed, whether a child went straight for the dessert, or if the child chose the junk food that predicted obesity. There were 2 things that did correlate with later obesity. The first was the amount of time the child spent at the table. Those who were there for 39 minutes or more and kept eating were less likely to become obese than the children who were at the table for 29 minutes or fewer. Taking longer for a meal appeared to be protective. An even stronger correlation, however, was found between the number of bites per minute and obesity. Those children who had eaten 3.1 bites per minute or more were much more likely to become obese than those who ate 2.2 bites per minute or fewer. That was a difference between about a bite every 20 seconds and a bite every 27 seconds. A 7-second difference in bites was enough to make a dramatic difference in weight.
A study of older children published in 2010 confirmed this association between speed of eating and weight loss. In this study, obese children participating in a hospital-based intervention were randomly assigned to 1 of 2 groups that received identical lifestyle modification education. The intervention group was also given a computerized device that provided real-time feedback that taught them to slow down their pace of eating. The intervention lasted a year for both groups. At the conclusion, both groups of children did lose weight; both groups had healthier BMIs and better cholesterol levels as well as other blood markers. However, the group that had received the feedback had a significantly better outcome in every category. Six months later with no intervening intervention, that group that had learned to slow down their eating had continued to make improvements. Slowing down the pace of eating to 1 bite every 30 seconds made a difference
Looking at infants, I wonder if this may be one of the reasons that breastfeeding is protective; breastfed babies have to work to eat. Perhaps passive feeding bottles are problematic because large amounts of formula can come in without the baby being able to regulate how much they are getting, resulting in feeding too quickly and too easily.
Medscape: The American Academy of Pediatrics’ Baby Center guidelines for parents of infants 4-6 months of age recommends pureed food and iron-fortified cereal. What more specific recommendations do you make for infants in your practice?
Dr. Greene: The current recommendations for feeding babies are not working. There was a 2011 study that looked at the obesity epidemic, which is no longer news, but this was news. At 9 months of age, 32% of the American babies in the study were already overweight or obese. This is dramatic and very different from earlier decades. This was not just healthy, chubby babies — these were children who were really overweight or obese by 9 months old.
At 2 years old, that percentage of obese children was 34%, a small increase. These figures illustrate that the bulk of the obesity epidemic is already starting in early childhood. So the thing that we need to be doing if we want to solve the obesity epidemic is to look at what is happening at 8 months old. A lot of our focus has been on reducing screen time, increasing exercise, providing healthier meals in schools, reducing fast food and drive-through windows, and getting rid of soda, and those are really good interventions. I support every one of them.
But at 8 months old, soda is not a big problem for most babies, certainly not for a third of babies. Lack of exercise is not a big issue for most babies, certainly not a third of babies. Drive-through windows even are not a big issue at 8 months old. What is it? If we want to find out what the big issue is, I would suggest we look at where kids are getting their calories. There must be some modifiable risk factor that is causing this obesity increase. I say modifiable because it did not used to be this way.
What many people do not realize is that the number one source of solid food calories for most babies in the United States, the number one calorie source from all solid foods, is refined white flour, refined grains, what we call white rice cereal. It is no wonder, I think, that we are ending up with a crop of obese children; we are priming them both metabolically and from a flavor perspective to like exactly the wrong thing. So I take strong issue with the idea of starting with white rice cereal.
Medscape: You have initiated a campaign called WhiteOut with a goal of introducing whole grains during the first year of life. Can you describe this program? What was the impetus for its development? Can you discuss the scientific foundation?
Dr. Greene: The specific goal of the WhiteOut Campaign is to eliminate white rice cereal for babies by Thanksgiving of 2011 — to whiteout or erase this, what I would term, mistake of the late 20th century. This is a grassroots campaign of patients, physicians, parents, everybody that we can get involved. There is no funding or commercial interest in this whatsoever. It is a public health effort to change the way babies are fed.
The taglines are very simple: let every child’s first grain be a whole grain. They won’t mind; they will thank us for it. And let every child’s first food be a real food, something that we want them to learn to like later.
This is not specifically saying that the first food should be a grain or shouldn’t be a grain. That is not the issue. Rather, our point is to just skip the white rice cereal. When parents do introduce grains, they should be whole grains.
Think about the reasons for choosing a first food for babies. One reason may be because the food is nutritionally dense and gives them what they need right now. That should not be a major reason because infants are getting most of their nutrients from breast milk or formula, but it is a legitimate reason. By that parameter, white rice flour offers no benefit; it is a food we would call a junk food at any other time. It does have a few added vitamins and minerals but you can get those in a whole grain just as easily.
Another reason that we might choose a first food is that it is hypoallergenic. However, the American Academy of Pediatrics has said that there is no food that we need to delay beyond 4-6 months of age because of concerns that it might increase allergies. That, therefore, is not a good reason for white rice cereal.
Another reason to choose a food might be because it is iron-fortified. There are healthy alternatives, whole grain oatmeal and whole grain brown rice cereals, that provide iron fortification similar to that found in white rice cereal. Or you could choose foods that are naturally iron-dense, such as meat.
The final major reason for choosing a food early on is to teach a child to like that taste. White flour is something we don’t want to teach children to like. Earlier, we talked about the need to expose a child to a particular food 6-10 times on average to allow the baby to learn to like it and continue to like it. However, 94% of parents won’t do this. The one food the parents feed again and again is white rice cereal. Most babies in the United States will receive that food 10 or 15 times, often before they have any other bite of food, solidly programming them to like it.
It is no wonder that kids’ meals across the United States include foods like mac-‘n-cheese, white flour buns on hamburgers and hotdogs, chicken parts dipped in white flour in order to make them appealing for kids. White flour and refined sweets are the number 1 source of calories throughout childhood. We are setting children up for that.
The new US Departments of Agriculture and Health and Human Services dietary guidelines recommend reductions in the following 5 foods in the American diet:
- Sodium, which is not a big issue for babies;
- Alcohol, which hopefully is not an issue for any babies;
- Solid fats, some of which are needed in the rapid growth first year of life, which is a time where fatty profile is not the big obesity issue;
- Added sugars, which babies should not be getting and is not a major part of their diet; and
- Refined grains, which are the number one source of solid food calories — something that should be reduced. This is our culprit.
On the flipside, the dietary guidelines encourage the inclusion of whole grains in diets because of evidence that indicates that whole grains can reduce the risk for cardiovascular disease, are associated with lower body weight, and, as an additional benefit, are high in fiber. There is also some evidence demonstrating that diets higher in whole grains may reduce the incidence of type 2 diabetes. American actually fall farther short in encouraging the use of whole grains as a replacement for refined grains than we do in getting kids to like vegetables. Yet, many parents get the recommendation to start their child on a refined grain and that message is repeated again and again. I think it is the worst choice we could make for a first food.
Medscape: What about availability of, for example, brown rice cereals? Are whole grain choices for infants readily available and, if so, are there cost implications?
Dr. Greene: The same manufacturers that make the refined white flour cereals also make whole grain versions and often at a very similar price. So for families who are buying cereal, there is not much of a cost implication. However, we have to keep in mind that about half of the babies in the United States are fed by the Women, Infants and Children (WIC) program, and white rice cereal is the dominant calorie source for foods provided to these families for use in the first year of life. For families on WIC who wish to provide their infant with whole grain cereal, there is a cost implication.
Availability is the other issue. While whole grain cereals are available in some store chains, they are not found in all of them yet. I have looked in a number of stores and found only white rice cereal on the shelves. That is one of the goals of WhiteOut: to change the store shelves this year to make whole grain cereals easy and available for families.
Another initiative of the WhiteOut program is to talk to decision makers within the WIC program about providing a whole grain cereal option for families. I can’t think of any reason not to do that. Long term, we would like to actually replace the white flour option for babies and not even have those covered under WIC.
Medscape: Can you discuss the parent education provided by the WhiteOut campaign?
Dr. Greene: For babies to see and taste the same foods that the family is eating is a very powerful thing. It is the way that babies were fed through most of human history. The whole idea of baby food is a pretty modern invention. When my father was born, it was not that way. By the time I was born, it was a rite of passage to eat processed baby food. Our campaign aims to change that.
My book Feeding Baby Green is a simple program to teach children to recognize and truly enjoy healthy amounts of great food — something I call Nutritional Intelligence. There are many supporting materials on my Website and on the WhiteOut page.
One of the options I recommend for families who want to start with grains is to include brown rice in the family diet and to make their own brown rice cereal themselves. I think that is one excellent way to go.
My preference for the first bite is to give a baby a bite of something they’ve seen the parent eat, something they’ve seen come from the produce aisle, a community supported agricultural farm, a garden, or a farmers’ market. I love avocados, sweet potatoes (cooked until soft), or bananas as a first bite — mashed with a fork with some of the breast milk or formula they’ve already been getting.
Parents have a strong inner drive to feed their babies well. The simple tip to let the first grain be a whole grain often makes sense to them when they hear it. How much better when they hear it from their child’s own provider!