One of the things I most love about the field of nutrition is that it is constantly evolving. There was a time when people with ulcers were instructed to drink small amounts of cream and milk throughout the day to buffer their stomachs against acid and reduce the irritation of the ulcer. Now we know that most stomach ulcers are caused by a bacterium that can be eliminated with medication.
People with diverticular disease were told to eat a low-fiber diet to avoid irritating the gut. Now we advise just the opposite, in most cases.
Twenty years from now, we’ll look back and remember how we used to tell new parents to hold off on introducing foods such as peanuts and eggs until the infant was at least 12 months old, in order to reduce the chance of triggering an allergy.
The newest advice―and it’s on pretty solid ground―is to introduce typically allergenic foods such as peanuts and eggs during the first year of life, even as soon as other solids are introduced, to help prevent allergic reactions.
Following the evidence
Why the 180-degree shift?
Quite simply, newer and better evidence, which is now strong enough that the American Academy of Pediatrics (AAP) recommends against delaying the introduction of solid foods past six months, even in exclusively breastfed infants. Moreover, the organization cites a study in its journal Pediatrics indicating that delaying introduction to known allergenic foods actually increased the chances of sensitivity to these foods, more so than if they were introduced earlier.
Indeed, delaying the introduction of eggs (beyond 10.5 months), fish (beyond 8 months), meat (beyond 5.5 months) and wheat (beyond 6 months) was “significantly and directly” associated with sensitivity to food allergens. Put simply, erring on the side of caution, which many parents would normally want to do, didn’t reduce the chances of a child being allergic to a food―it increased them.
This isn’t the only study that showed benefits from early introduction of allergenic foods. The food that’s probably top of mind for parents is peanuts. If you have a peanut-allergic child or know one, you know that the reaction in an allergic child can be life-threatening. Kids carry EpiPens to school, households are often cleared of all peanut-containing foods and playmates have to be prevented even from eating peanut products around the allergic child, to prevent possible contamination.
Infancy and food exposure
Exposure to peanut foods during infancy, however, could help prevent this. Indeed, there is no longer any credible evidence of benefit from delaying the introduction of peanut foods to an infant after six months of age. Instead, there is evidence in the Learning Early About Peanut Allergy (LEAP) study that introduction of peanuts as early as at ages four to six months in some infants at higher risk for developing peanut allergy may be not only safe, but effective.
And the benefits of allergen exposure go beyond foods. Kids who grew up on farms or in homes where pets such as cats and dogs were always present tend to have fewer allergies―not just to foods, but also to inhalant allergens such as pollen and pet dander―and healthier gut bacteria.
Does this mean healthier gut bacteria are the key to allergy prevention? There has been a lot of interest in supplementing infants with probiotics, which are the “good bacteria” present in foods such as yogurt, with the idea being that a stronger gut immune system would help the infants resist allergic responses. However, the quality of evidence has been spotty, although there appear to be no hazards to probiotic supplementation.
Like many, I have wondered if the age-old practices of withholding common allergenic foods such as eggs, peanuts and fish, and of creating an overly sterile environment for our infants, actually put them at an immunological disadvantage. Studies such as the LEAP allergy study and others suggest that the answer is “yes” and have shifted not only the thinking of organizations such as the AAP but public health policies and recommendations as well.
Changing long-standing beliefs and practices, especially those originating from respected organizations, is often met with resistance. It’s taken an entire generation to correct the mind-set that linked eggs with heart disease. Let’s hope that it won’t take a whole generation to rewire our beliefs about strategies for reducing infants’ risks for food allergies.
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One of the biggest questions I have is why are peanut allergies so prevalent now. I am 62, knew no one with a peanut allergy. My children are 32 and 28 – same story. Not one friend of theirs had a peanut allergy. So a better question is not when to introduce peanuts, but WHY there are so many peanut allergies now. But medicine is not in the business of “why” – it seems to only be in the business of “now”. (I am an IBCLC. Instead of asking/researching why ankyloglossia is so prevalent now, we are busy trying to treat it and make breastfeeding happen – at least those of us who are not denying its existence.)