The Health Concerns of Feeding Babies too Soon

Breastfeeding is a trendy thing right now. Am I right?

From cutesy nursing covers being a go-to baby shower gift to almost 1 million photos on Instagram being tagged #breastfeeding, the public is often pretty public about this issue.


Except when it's not.

As may be assumed, I am pro-breastfeeding. I do believe it is the ideal choice for infant nutrition, if and when it is possible to be provided. That being said, I am also a parent who has had my fair share of hardships breastfeeding both of our daughters. I am also a health practitioner that knows far too well,

What is trendy is not always what is true. What is public is not always portraying what is private.

Breastfeeding is no exception, especially in its relationship with starting solids.

According to the 2014 CDC Breastfeeding Report Card, four out of five moms tried breastfeeding. Of those, approximately half were still breastfeeding at six months and about a quarter by one year. More applicable to our conversation here, is that only 40% of mothers were exclusively breastfeeding at three months and only 20% at six months.

A study published in the journal Pediatrics in 2013 found that overall (among breastfed, formula-fed, and mixed-fed infants), 40% of mothers introduced solid foods before 4 months. The proportions of infants who were introduced to solids according to the recommended age range (between 4-6 months) was highest among infants receiving only breast milk, when compared with formula and mixed-fed infants.

These statistics and findings are concerning when it comes to the conversation about introducing solids. We know that the early introduction of solids ends exclusive breastfeeding and has been associated with reduced duration of any breastfeeding. Given the important health benefits of breast milk, any interference with breastfeeding an infant, especially at this age, would be unadvised. Additionally, the health concerns of feeding babies too soon (prior to 4 months) may increase an infant's risk of some chronic diseases, such as diabetes, obesity, eczema, and celiac disease. On the contrary, waiting to introduce solids until at least 4 months can improve the health-related outcomes an infant experiences both in the short and long term.

In this series, you are learning:

I. The expert opinions are on when to start solids

II. The health concerns of feeding babies too soon, too late, or right on target

III. The opportunities for how to start solids at the best age and stage

health concerns of feeding babies too soon

In this post, we will cover many of the health concerns of feeding babies too soon, too late, or right on target.

When infants are given solid foods before 4 months or after 6 months of age, there are nutritional, allergic, chronic disease, and developmental risks associated with the introduction of solid foods. For this reason, introducing solid foods between 4-6 months is recommended for the more positive role it plays on each of these health-related outcomes.

Where applicable, some of the health concerns of feeding babies too soon and/or too late are included in italics following the associated health concern for introducing solids during the 4-6 month range.

Let's address these health-related concerns here.


One of the leading reasons parents introduce foods early is because they believe their infant appears hungry, needs more than milk for proper growth, or out of concern for iron and/or zinc deficiencies. Many similar hypotheses have been tested by leading researchers to conclude the following:

Infants are good at intrinsically regulating their food intake.

Infants who are exclusively breastfed until 6 months have been found to have similar nutrient intakes to infants who were introduced to solids at 4 months. Although the source of their calories differed (between 100% breast milk and breast milk+solids), the overall caloric intake was not significantly different. Read more about such research here.

Infants will grow according to their normative patterns.

When fed within the 4-6 month window, there is no benefit nor deficit to infant's growth. Infants who are exclusively breastfed for six months do not show deficits in anthropometric measures such as height, weight, or body mass index (BMI). Read more about such research here.

Infants iron status is important at this age.

Many studies have researched if iron status is improved in infants who are exposed to complementary, iron-rich foods earlier versus later (ie. 4 vs. 6 months). Although infants introduced to solids at an earlier age often have higher iron stores at 6 months (compared to infants exclusively breastfed for 6 months), iron levels were adequate in both groups. According to one study, the number of infants with iron deficiency or iron deficiency anemia was not significantly different between those introduced to solids earlier versus later.This suggests that although infants introduced to solids at 4 months may have a higher or perceived "better" iron status, the difference may not be significant when compared to healthy infants who are exclusively breastfed until 6 months. Note this does not apply to infants who are introduced to solids after 6 months. Delaying solids beyond 6 months does increase an infant's risk of iron deficiency.


In 2003, the American Academy of Pediatrics (AAP) released a statement recommending the delayed introduction of highly allergenic foods in "high risk" infants.  Such guidelines advised not introducing cow’s milk until age 1 year; egg until age 2 years; and peanuts, tree nuts, and fish until age 3 years were recommended. Unfortunately, we saw a dramatic increase in the incidence and prevalence of food allergy and allergic disease in the years after these guidelines were given. And yet, these recommendations that suggest waiting to introduce top allergens are still ingrained in many of our minds.

We know now though that the timing certain foods are introduced might matter when it comes to preventing food allergies and atopic disease (like eczema and asthma). It is unclear why earlier research showed delayed introduction of solid food to be preventive. However, current data does support how these recommends have changed over the last decade to support earlier introduction of solids as preventative. A retrospective database review was part of the emerging data out there to defend that early introduction of some foods might actually be protective (that is, increase food tolerance and prevent food allergy). Some of the key points found in current research suggest:

Complementary foods can be introduced between 4 and 6 months of age.

Both of the leading organizations for allergies and immunology in America and Europe agree that the introduction of complementary foods should not be before 17 weeks but should not be delayed beyond 26 weeks.

Don't delay the introduction of cow’s milk protein (except for whole cow’s milk), egg, soy, wheat, peanut, tree nuts, fish and shellfish beyond 4-6 months of age.

Once a few typical complementary foods are tolerated, highly allergenic foods may be introduced as complementary foods.

Chronic Disease

Introduce gluten gradually while the infant is still breast-fed.

According to recent studies, families should focus more on introducing antigens (like gluten) while infants are still breast-fed than targeting a specific age at which to introduce such foods. Research does indicated the infants exposed between 4-6 months however may have lasting protective effects against the development of Celiac Disease and Type 1 Diabetes Mellitus. More current summaries of studies done on preventing Celiac Disease (such as this excellent article by Science of Mom) highlight that infants considered "high risk" (for Celiac Disease) may benefit from waiting until 12 months of age before being introduced to gluten.

In developed countries, the risk of infection is not increased according to the age an infant starts solids.

One of the reasons exclusive breastfeeding is often encouraged in developing countries is due to the poor sanitation and access to safe resources like clean water and refrigeration. In such environments, introducing solids opens up an unwanted opportunity for exposure to pathogens that may increase an infant's risk of infection. infection in infants. Research in developed countries suggests that an infant's risk of infection is not significantly higher among those who had received solids versus those who had not, nor did the risk vary according to when an infant starts solids.

Starting solids between 4-6 months does not appear to have a clear impact on the risk of obesity.

According to European Food Safety Authority (EFSA) Panel on Dietetic Products, Nutrition and Allergies, starting solids between 4-6 months of age does not have a strong impact on growth velocity (both weight and length) nor risk for obesity later in life. A few studies have suggested, however, that early introduction (before 4 months) could result in an increased rate of weight gain. This could lead to long term consequences of increased risk for chronic diseases (ie. obesity, type 2 diabetes and cardiovascular disease) later in life. Data also suggests that late introduction (after 6 months), could decrease an infant's growth. 


According to EFSA's 2009 report on "The Appropriate Age for Introduction of Complementary Feeding of Infants," existing evidence does not conclude a specific age at which solids need to be started for the sake of neuromuscular development nor development of food preference. Additionally, solids started after 4 months of life do not constitute a problem for the digestive system or the renal function of the infant.


In Summary

Several pieces of evidence suggests that there is no significant difference in an infant's health when offered solids between the range of 4-6 months (or more specifically, >17 weeks and <27 weeks). Research even points to a few reasons why solids should be introduced between 4-6 months (instead of exclusive breastfeeding until 6 months). These include the impact earlier introduction has on lowering an infant's risk for iron deficiency and lowering their risk of food allergies and type 1 diabetes.

Does it seem strange to you then that expert recommendations continue to suggest 6 months of age is the ideal for when to introduce solids?

It does (or did) to me too. Until I began researching a bit more about developmental readiness for starting solids.

In the next and final post from this series on "When to Start Solids," we will highlight why the most important advice of all on when to start solids is to:

Focus on your infant's cues, not the calendar.