Thursday, July 12, 2012

Pediatricians Cause Food Allergies!

You may have seen media references to a new study out this week: Infant Feeding Practices and Nut Allergy over Time in Australian School Entrant Children

The headlines have been quite sensationalistic:

Children With a Regular Doctor More Likely
To Have Food Allergies!

Seeing The Pediatrician Linked To Allergies

Child Have An Ear Ache? Think Twice About That
Routine Trip to the GP...

I'm sure you've seen these headlines splashed across your various news feeds.


Well, how about these then?

Oh, yeah, those you've seen! 

Here's the thing: the study referenced above actually found a correlation between both things. Children who were nursed exclusively during the first six months of life were slightly more likely to have a nut allergy. About the same level of risk was found for children who regularly visited their doctor

I know news organizations are desperate for controversies that will pump up readership...but this just seems so WRONG and STUPID! Now there will be another round of new mothers afraid of breastfeeding, afraid of peanuts...all because of a study that has, buried in all the biased language, an important line:

Also, the study design does not allow causality to be inferred.

Stop and think beyond the sensationalism for a moment. We KNOW there is a sensitizing agent/experience involved with food allergies. Somewhere along the line, a baby's immune system is encountering proteins to which it develops a response that later becomes a food reaction.

These sensitizing proteins may very well be in breast milk. However, those same proteins may be on Mom's hands after she made that peanut butter sandwich, or inhaled as pollen that has potential for cross-reactive immune mix-ups. They may be trace amounts in baby foods or baby products. There may be some other entire mechanism for sensitization that we do not yet understand.

This study from the early 90's took the issue of sensitization and breast milk on directly. Mothers were asked to avoid milk, egg and fish while nursing. While initially the babies in the avoidance group showed lower levels of IgE antibodies (in other words, sensitization), over time, the avoidance had no effect on whether the babies demonstrated an allergy. (Here's a comprehensive  and far less biased  review of studies related to maternal avoidance of proteins and the effect on food allergies.)

The point is that the set-up for the sensitization is already in place by the time the protein is introduced. Withholding foods probably doesn't prevent an allergy, but simply delays it. And the fear is that, the longer we wait to expose children to foods, the more opportunity the body may have to develop that environment/trigger/mysterious occurrence that leads to sensitization. That's why doctors shifted back to telling moms to eat the peanuts. Keeping them in the diet seems to do less harm overall. Perhaps they advice will shift yet again with this study...but does it really even matter?

The bottom line is: humans have been nursing babies and eating nuts for hundreds of thousands of years and very few of those babies became sensitized. 

Sensitization is not the answer, or really even a large part of the puzzle. The question is why some children become sensitized and why it is happening now, in the last 20 years, in so many children. The protein involved (like peanut) is also not a large part of the puzzle, because the common allergens change as a culture's food changes. We know babies tend to become allergic to foods that have the right molecular weight and allergenic properties that are most commonly eaten by the population into which they are born. 

This study seems to be implying that somehow changing the window of solids introduction from four to six months is enough to tip Mother Nature over into suddenly creating an epidemic of food allergies. Am I the only one that thinks that conclusion is just flat-out stupid?

It's almost as stupid as looking at the data in this study that was JUST AS STRONG in favor of a link between visiting the doctor and food allergies...and concluding that doctors cause food allergies.

But, then, the Mommy Wars don't revolve around doctor visits. They do revolve around the decision to nurse. Easy to see why these publications would focus on one and leave the other behind.

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  1. I'm in Australia and the article was EVERYWHERE. On the TV news, radio news and I'm assuming it will be in the weekend paper tomorrow too. I was sent it by half a dozen people because I'm breastfeeding and have a child with a severe cashew allergy.
    Your article was VERY refreshing to read and I'll be passing it on.

  2. Ahhhhhhh, yes. Correlation fallacy, like irony, is not dead.

    Pretty much no matter what it turns out to be, you KNOW that we parents are somehow going to be to "blame" for it, right?

    Yeah, I'm not any happier about that than anyone else. So I have to laugh at how stupid some of the interpretation of the research studies is (and really, even how dumb some of the population research is) or I'd cry instead.

    If only I'd known to keep my child away from the doctor and feed her more cat poop. Hmmm. Wonder if dog poop is okay instead... I wonder if there is a correct AMOUNT of poop...


  3. I don't want to hit on something too controversial as I just stumbled on this blog and really love it and don't want to offend anyone. Anyway, I have a baby now and am of course trying to avoid what happened to my firstborn son who has the milk, egg, nut, seed allergies. As I'm faced with choices on what to do, I can't help but wonder whether the HIb vaccination plays a role in sensitizing kids to the peanut allergy. There's a book that hypothesizes that the vaccine antigen cross-reacts with peanut and certain tree nuts because th

  4. (Cont) molecular weights are the same. By conjugating a toxin to the Hib shell, the infant's body is supposed to be "tricked" into forming an immune response. But, in genetically or otherwise environmentally susceptible infants, the body becomes allergic to the hib protein and to peanut. So, I know this is a divisive subject, but I'm really wondering what other allergy moms think of this. I would hate to think I protected my son from an infant disease in return for a lifelong threat.

  5. Sounds good, doesn't it? Sounds like something you would *want* to believe. That's the hell of how polarization works. We have an emotion that doesn't belong to a logical fear. So we look around until we find a thought that fits that emotion. Like vaccines cause food allergies.

    Obviously I'm not a fan of the theory, although I really can't evaluate it since I'm not a biochemist. However, I have friends who ARE biochemists and they say it's bunk. Therefore, my logical mind has to wrestle with my emotional mind. Even though it was hard for me, I gave my two children all their shots...because I trusted my friends and my pediatrician to know more than my gut did.

  6. Your post got me thinking about the vaccination angle because of the title, as in, what if pediatricians DO cause allergies? I would like to see this Hib vaccination hypothesis tested, because right now it is just a scary what if that makes it harder for me to feel good about the decisions I make as a mom.

    If the theory is true, then wouldn't a large number of peanut allergic kids have abnormal IgE and/or other immune responses to the Hib antigen? I'm not an immunologist of course, but this doesn't seem too hard to prove or disprove.

    By the way, I asked a doctor friend about this after she brought up a crazy friend who thought vaccinations were unsafe. A couple weeks later, she said that her mom, who is a "very conservative" pediatrician, researched the idea and found it plausible. So, really, who knows? And why can't we find out?

  7. There's no reason research can't go in any direction. However, there's an important distinction between suggesting a research study and choosing not to vaccinate a child on the basis of a possibility.

    Russell's teapot is the slippery slope of polarization. In the meantime, kids are dying because of vaccine deniers and misinformation.

    I know which side of that line I want to be on.


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