If you’ve had a baby in the last few years, you may have been confused about when, exactly, to introduce common allergenic foods, like peanuts, cow’s milk, eggs, and shellfish. You may have heard that delaying these foods beyond one year of age can help prevent food allergies. The American Academy of Pediatrics reversed their official recommendations to delay allergenic foods until over a year of age in 2008, but there hasn’t been a whole lot of clarity on when and how to safely introduce allergens during infancy.
In Spring of 2020, Food Allergy Research & Education (FARE) — the world’s largest nonprofit organization dedicated to food allergy awareness and improving the lives of those with food allergies — launched their Baby’s First resource to raise awareness of the benefits of the early introduction of a wide variety of foods to help reduce the risk of food allergies in babies.
Below, Dr. Ruchi Gupta, MD, MPH, answers questions on the science of introducing allergenic foods to babies. Dr. Gupta is a Professor of Pediatrics and Medicine at Northwestern University Feinberg School of Medicine and a Clinical Attending at Ann & Robert H. Lurie Children’s Hospital of Chicago. She’s also FARE’s medical advisor on Policy, Education and Public Health, and lead spokesperson for Baby’s First.
Highlights:
- The American Academy of Pediatrics changed its position in 2008 because there was a lack of evidence that delaying the introduction of allergenic foods could prevent food allergies. In 2015, studies showed that introducing allergens in infancy can reduce the incidence of food allergies.
- No strategy for avoiding food allergy is perfect. Parents shouldn’t blame themselves if their children develop food allergies.
- The most significant risk factor for developing food allergies is severe eczema.
- Always work with your pediatrician and consider your family’s preferences.
- If you have any concerns about your baby’s response to a new food, seek medical attention right away.
- You can find evidence-based advice from pediatricians, allergists, and dietitians at babysfirst.org.
FARE launched Baby’s First in April of this year. Until 2008, the American Academy of Pediatrics (AAP) recommended delaying cow’s milk until 1 year of age, eggs until 2, and peanuts and shellfish until age 3. Why the launch of Baby’s First now, twelve years since the evidence came in that delaying allergens doesn’t protect against developing food allergies?
Dr. Ruchi Gupta: AAP changed its position in 2008 because there was a lack of evidence that delaying the introduction of allergenic foods could prevent food allergies. In 2015, researchers found very solid evidence that early introduction of peanuts– the opposite of delayed introduction – could help prevent peanut allergy. The 2015 Learning Early About Peanut Allergy (LEAP) study showed that high-risk children who ate peanuts early (between 4 and 10 months) and often had an 80% lower prevalence of peanut allergies than children who avoided peanuts until the age of five.
The importance of these findings was recognized when the LEAP study was published, and AAP endorsed the 2017 Addendum Guidelines for the Prevention of Peanut Allergy. These guidelines encouraged the introduction of peanuts especially in high risk babies after testing and discussion with their physician. AAP also released recent guidance on early nutrition, which incorporates the LEAP study findings into its advice on introducing peanut-containing products.
There is also growing evidence that early introduction of egg can significantly lower rates of egg allergy in children at high risk. And more broadly, studies on diet diversity indicate that eating a wider variety of healthy foods during infancy can lower the risk of developing food allergy.
There has been significant progress made over the last decade to show the importance and outcomes of introducing foods early to reduce the risk of developing a food allergy, and now is an essential time to launch Baby’s First.
In some places, the American Academy of Pediatrics recommends that infants be exclusively breastfed for the first six months. But in others, the AAP suggests that infants can have single-ingredient foods at 4-6 months. Which one is correct?
RG: This is a very interesting question. Breastfeeding for the first six months is recommended. Food introduction is recommended by most pediatricians when the baby is developmentally ready, and this happens somewhere between 4-6 months for most babies. From what we know now, data suggest that the children who benefit the most from introduction of allergenic foods like peanut and egg as early as 4 months are the children who are at highest risk of developing food allergy. For these children who are predisposed to allergic conditions, whose skin is likely to be damaged by eczema, it’s best for their first exposure to allergenic foods to be through their mouth, rather than through their skin, because introduction through the mouth appears to promote food tolerance, whereas introduction through the skin teaches the body that the food proteins are invaders, and this can lead to food allergy.
The AAP guidance on six months of exclusive breastfeeding predates the LEAP study, so it doesn’t reflect what we now know about the benefits of early peanut introduction, particularly for babies at high risk for peanut allergy. We also know from the Enquiring About Tolerance (EAT) study, which was published in 2016, that introducing allergenic foods to babies at 3 months didn’t disrupt breastfeeding between 3 and 6 months, so early introduction and breastfeeding are compatible.
After the LEAP study was published, an expert panel was convened by the National Institute of Allergy and Infectious Diseases (NIAID) to develop guidelines for parents and physicians based on the new evidence that eating peanut foods early could protect against peanut allergy. AAP’s 2019 guidance on early nutrition endorses the NIAID guidelines, which vary based on a baby’s risk for peanut allergy. For babies at low risk, families can introduce age-appropriate peanut containing foods when and how they like, so long as the peanut foods aren’t choking hazards. For babies who are at moderate risk for peanut allergy because they have mild or moderate eczema, NIAID recommends introduction of peanut foods around 6 months. For babies at the highest risk, who have severe eczema, an egg allergy or both, NIAID encourages parents to first have their baby tested to see if the baby has already developed peanut allergy. If the baby isn’t already allergic to peanut, they are better off eating age-appropriate peanut containing foods as soon as they can, as the risk of developing a peanut allergy increases as the baby gets older.
There’s a pervasive idea that a baby’s digestive tract or “gut” isn’t mature enough to digest anything but breast milk until 6 months of age. Does this mean parents should wait to introduce solids until the 6-month mark?
RG: If a baby isn’t at elevated risk for food allergy, I recommend taking cues from the baby to assess whether they’re ready for solid food. Are they sitting upright with good head control? Do they express interest in what you’re eating? Can they take food from a spoon? If a child is at elevated risk for food allergy, though, the potential benefit of early introduction is also enhanced, and that potential benefit has to be weighed alongside the baby’s feeding cues. Also, always work with your pediatrician and consider your family preferences. Breastfeeding exclusively until six months of age in low or moderate risk babies is absolutely fine. If the baby is at high risk, discuss with your pediatrician and allergist how to proceed but do begin the evaluation around 4 months.
How does introducing common allergens early prevent food allergies? This seems counterintuitive.
RG: This goes back to the current theory around whether a baby’s first exposure to a food is through the mouth and the gut, or through the skin. When a baby eats proteins, which are the parts of food that can trigger an allergic reaction, we think that signals are communicated to immune cells in the lining of the mouth and the gut that say “These proteins are food, they’re in the right place,” so that the immune system tolerates those food proteins. If those same food proteins enter the body through a broken skin barrier due to eczema, the signaling to the immune system says, “These proteins are in the wrong place,” so that the immune system learns to defend against those proteins, and that’s what an allergic reaction is.
If a child waits two or three years to eat egg or peanut, they’re still likely to come into contact with those foods in the environment. And if their skin barrier is damaged by eczema, those environmental exposures to allergenic food through the skin are more likely to trigger changes in the immune system that can lead to food allergies.
What are the risk factors for an infant developing a food allergy?
RG: The most significant risk factor is severe eczema. It is so important to protect the skin barrier and reduce eczema flares in infancy. If your baby has eczema, definitely discuss this with your pediatrician early and see a dermatologist if needed. If it continues, it is important to get tested and/or see an allergist around 4 months.
We also know that genetics play a role. Your child’s odds of developing a food allergy are greater if there’s a family history of food allergy or other allergic conditions like eczema, asthma, or allergic rhinitis (hay fever). This doesn’t mean that a baby will inherit peanut allergy from a parent with peanut allergy, or milk allergy from a parent with milk allergy. It just means that a baby with a family history of allergies is more likely to develop any type of allergy.
Additional factors that appear to decrease the risk of developing allergic conditions include living in a rural area, having pets (especially dogs), being delivered vaginally, and not being treated with antibiotics during infancy. These findings suggest that having a wider variety of microbes living in the baby’s gut and on the baby’s skin may offer some protection.
Finally, it’s important to know that no strategy for avoiding food allergy is perfect. There are some babies who will develop food allergies even if they are born on a farm, require no antibiotics, and are given allergenic foods early. Parents shouldn’t blame themselves if their children develop food allergies.
Is there a test that can determine whether an infant will have an allergic reaction before introducing the common allergenic foods? Should infants be tested for food allergies?
RG: For a baby who is at low risk of developing a food allergy, who has no eczema or mild to moderate eczema, doctors don’t generally recommend allergy testing before introducing allergenic foods. For a baby at high risk for food allergy, who has severe eczema or who has already developed a food allergy, consulting with your pediatrician or allergist before introducing commonly allergenic foods is strongly recommended. Your doctor will recommend allergy testing and/or referral to an allergist.
Blood tests can measure food-specific IgE (allergy-associated) antibodies in blood serum. Skin prick tests can measure skin reactions (wheals) that develop in response to being pricked with a probe dipped in a solution that contains food extract or protein. Both tests show whether the baby has become sensitized to a food, that is, whether the baby makes IgE antibodies that can bind to a food. However, tests results that show a baby has been sensitized to a food don’t always mean that the baby is allergic and will react to eating the food.
For example, if a baby has a negative peanut-specific IgE, they most likely do not have a peanut allergy and can start peanut containing foods in their babies diet. If the peanut-specific IgE is positive the baby needs to see an allergist for further testing with a skin prick test. Depending on the size of the skin reaction (wheal) the allergist will recommend introducing peanut-containing products at home, in the office or not at all.
Can parents safely introduce allergenic foods at home? Where can parents get reliable information on how to introduce new foods, including common allergens?
RG: You can find evidence-based advice from pediatricians, allergists and dietitians at babysfirst.org. We recommend that other single foods, like pureed fruits or vegetables, be introduced first, before commonly allergenic foods, so that you know that your baby is ready for solids. Pick a time when your baby is healthy and can have your full attention for at least two hours. Start slow and feed gradually, watching for signs of an allergic reaction.
The first symptoms of an allergic reaction to food usually appear between a few minutes and two hours after eating or other exposure. Symptoms can range from mild to very severe or even life-threatening. You could see one symptom or many. Examples of mild symptoms might include a new rash or a few hives around the mouth or face. More serious symptoms might include swelling of the lips, face or tongue; vomiting; diarrhea; widespread hives over the body; wheezing; repetitive coughing; difficulty breathing; skin color changing to pale or blue; sudden tiredness or lethargy; or seeming limp. The most common symptoms in babies include hives and vomiting.
If you have any concerns about your baby’s response to a new food, seek medical attention or call 911 right away.
For parents with a family history of food allergies, should they follow different advice? Are there other conditions that might suggest a different approach, like eczema?
RG: As noted above, severe eczema puts a baby at high risk for food allergy. Before introducing allergenic foods, consult with your pediatrician or allergist and consider allergy testing. For a baby with moderate or mild eczema, you should always feel free to raise any concerns you have about food introduction with your doctor. Some parents and doctors might choose to introduce foods in the doctor’s office, so that help is nearby if the baby reacts.
We don’t have the same sort of strong experimental evidence on which to base recommendations for babies who have a family history of allergy but no eczema. Again, consulting with your doctor can be helpful in weighing the approach that’s best for you and your baby.