Tuesday, February 10, 2015

Headline hyperbole - probiotics cure peanut allergy?

Note about study discussed below – please do not try oral immunotherapy (OIT) or OIT with probiotic supplements on your own! This is an experimental food allergy treatment to be performed under strict medical supervision.

Sigh… We all want a cure, and many scientists/clinicians are working tirelessly toward that goal (including the research group that performed the original peer-reviewed study(1)), but please, oh please media, stop overselling the scientific findings! I’m quite literally tired of having to explain the same thing over and over again! Unfortunately, there is a reason why one of my blog labels is now “Misleading Science Headlines.” I don’t necessarily want to go into the details of why this is so detrimental to both the science and food allergy communities, but rather I’d like to take the rest of this two part post to explain why the headlines got it wrong, what can actually be concluded from the study, and where the science may go from here. Lianne Mandelbaum, who founded No Nut Traveler, authored an excellent piece at the Huff Post Blog explaining why misleading headlines are such a problem when it comes to food allergies. I encourage you to take a read.

Brief summary of the study:

Mimi Tang, et al., from the Royal Children’s Hospital in Melbourne, Australia tested if the combination of oral immunotherapy (OIT) and a probiotic supplement could lead to “sustained unresponsiveness” in peanut allergic children compared to a placebo group  (peanut allergic children who did not receive peanut OIT or probiotic). They found that after stopping treatment (ranging from 2-5 weeks) over 80% of children who received OIT + probiotic maintained a “sustained unresponsiveness” to peanut compared to only 3.6% of the placebo group (1).


Study design: Randomized, double-blind, placebo-controlled

Why the headlines got it wrong:

1.  “Fatal peanut allergies” can’t be cured. I admit this is a bit of a cheap shot, and perhaps being overly pedantic, but if an allergy is “fatal,” it means that a person doesn’t survive. Last I checked, curing something fatal is akin to walking on water. Perhaps they meant to say “potentially fatal peanut allergies….?”

2.  Cure vs. Treatment. Dear science/medical writers in the media, please understand this distinction. Either you and your editors are completely clueless, or you are knowingly using the word “C-word” where it should be a "T-word" to disingenuously drive more internet traffic to your site. In some cases, treatments may lead to a cure and in other cases, ongoing treatment may just keep the symptoms at bay. When it comes to food allergies, a “cure” would mean that after undergoing some kind of treatment, the food allergy is gone for good without further intervention. Hypothetically, a previously peanut allergic individual could go weeks, months or even years without eating peanuts and then safely consume peanuts with no fear of a reaction.

Oral immunotherapy (OIT) is not considered a “cure” at this point. It is a current, investigational “treatment” for food allergies whose outcome remains uncertain. And while I’m at it, OIT is far from “new,” as some headlines may suggest. What made this study novel from previous OIT studies is that it combined OIT with a probiotic supplement (more on that soon!). Scientists/clinicians consider OIT a “treatment” or “therapy” because we still do not know the long-term outcome.

For those of you unfamiliar with OIT, a person consumes their allergen in small, gradually increasing doses over a fairly long period of time (in this particular study, 18 months), until they reach some stable daily maintenance dose of their allergen. The idea is to “desensitize” or make the immune system unresponsive to the allergen. Very few studies have looked at long-term outcomes for individuals who have undergone OIT. A few that have looked, show that severe allergic reactions can come back full-force if a regular schedule of doses to the allergen is not maintained over time (i.e. continued treatment).(2)(3)(4)

I don’t mean to sound too glum, so I will point out that for many allergic individuals, OIT is a huge, liberating step forward in quality of life! But, please don’t call it “cure.” We honestly do not know.

3. Tolerance vs. desensitize vs. sustained unresponsiveness? All of these terms sound the same, right? They are certainly used interchangeably by the majority of headline writers. To an allergist/immunologist, however, they mean VERY different things and nothing likely makes them bristle more than hearing OIT study results reported as “kids tolerating” their allergen. Science is pedantic, what more can I say? Given that most of you reading this are dealing with allergies, please learn the distinction in the terminology and make your allergist proud at your next visit if you discuss OIT!

One of the aspects of this scientific paper that I really appreciate was a brief review of terminology surrounding OIT studies:

Tolerance = the sustained ability to consume a food without a reaction (i.e., a cure). Children who outgrow their allergy are said to tolerate a food.
Desensitization = the transient ability to consume a food without a reaction that is lost when OIT is stopped (i.e., long-term treatment to prevent reactions; not a cure)
Sustained unresponsiveness = the sustained ability to tolerate a food after OIT treatment is stopped whose long-term outcome remains unknown. This term conveys the uncertainty of whether this state is true tolerance or desensitization.

“Sustained unresponsiveness” was actually new terminology to me, but the rationale for using it makes complete sense. This terminology is proposed in lieu of “tolerance” when discussing follow-up of OIT studies.(3)  The reason being is that usually OIT studies will food challenge the allergen after some defined period of not consuming the allergen (e.g., 2 weeks, 4 weeks, etc., after stopping treatment). The fact is, someone could stop consuming their allergen for 2 weeks and be just fine, but what would happen after 4 weeks or more? We just don’t have the long-term data yet and allergists are not comfortable calling this “tolerance.” Ideally, what we need is a “biomarker” for tolerance - some test that could definitively indicate that the allergy is gone for good (i.e., tolerance) vs. desensitized. Until we have that biomarker, we must be comfortable with being uncomfortable – the uncertainty of “sustained unresponsiveness.” People who have undergone OIT will continue to carry epinephrine and be prepared to respond to allergic reactions for the foreseeable future.

4.  Eating yogurt is NOT going to cure a peanut allergy. Contrary to headlines such as “Yogurt could be key to potential peanut allergy cure,” the treatment is not as “easy” as headlines suggest. I know I speak for many food allergy affected when I say, please for the love, please stop making extrapolations of scientific data where they shouldn’t be made. I love my well-intentioned friends and family way too much. I’m tired of having to explain reality and raining on the parade of great intentions that somehow I missed a “simple” cure for food allergies!

Could probiotics,  i.e., good bacteria, help? Maybe, but it likely isn’t going to work in the absence of OIT, although this comparison has yet to be rigorously tested. Interestingly, within the text of the horribly titled article mentioned above, this little nugget emerges, “Half were also given a daily dose of a probiotic called Lactobacillus rhamnosus, which is found in yogurt (granted, the dosage was equal to more than 100 of those plastic kiddie containers of Yoplait), while the rest received a placebo.” That just straight up sounds like “kiddie” (and parent!) torture.

Stay tuned for Part 2.  I will be discussing what can actually be concluded from the study, and where the science may go from here! In the meantime, feel free to share the most egregious headlines and well-intentioned advice you have received in the comments section below!

References


1. Tang MLK, Ponsonby A, Orsini F, Tey D, Robinson M, Su L, et al. Administration of a probiotic with peanut oral immunotherapy : A randomized trial. J Allergy Clin Immunol [Internet]. Elsevier Ltd; Available from: http://dx.doi.org/10.1016/j.jaci.2014.11.034

2. Vickery BP, Scurlock AM, Kulis M, Steele PH, Kamilaris J, Berglund JP, et al. Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy. J Allergy Clin Immunol [Internet]. Elsevier Ltd; 2014;133(2):468–75.e6. Available from: http://dx.doi.org/10.1016/j.jaci.2013.11.007

3. Burks AW, Jones SM, Wood R a., Fleischer DM, Sicherer SH, Lindblad RW, et al. Oral Immunotherapy for Treatment of Egg Allergy in Children. N Engl J Med [Internet]. 2012;367:233–43. Available from: http://www.nejm.org/doi/full/10.1056/NEJMoa1200435

4. Keet C a., Seopaul S, Knorr S, Narisety S, Skripak J, Wood R a. Long-term follow-up of oral immunotherapy for cow’s milk allergy. J Allergy Clin Immunol [Internet]. American Academy of Allergy, Asthma & Immunology; 2013;132. Available from: http://dx.doi.org/10.1016/j.jaci.2013.05.006

7 comments:

  1. Thank you, thank you, thank you. Eagerly awaiting part deux.

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  2. Hi Jessica - Thanks for spelling this out for us so simply! Now I know what to say to all the folks who tell me they have found a cure. Can't wait to read part 2. Hope you and your family are well. Best - Justin

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    1. Thanks, Justin! I hope all is well for your family, too!

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  3. I have never heard of using probiotics to help cure peanut allergies. I have a nephew with nut allergies and it would be so helpful if a cure was found. We have to be so careful about what food we have around him. It would interesting to see the results of this study. http://www.allergypartners.com/fredericksburg/sitepages/Allergist.aspx

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    1. Thanks, Rachel. We all so much want a cure! Probiotics are definitely promising, but certainly we're only at just understanding if and how they may work. Part 2 is coming soon, I just really needed to comment on the LEAP study first. Cheers!

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