tag:theconversation.com,2011:/global/topics/peanut-butter-7473/articlesPeanut Butter – The Conversation2023-05-04T12:09:48Ztag:theconversation.com,2011:article/2037162023-05-04T12:09:48Z2023-05-04T12:09:48ZPeanut butter is a liquid – the physics of this and other unexpected fluids<figure><img src="https://images.theconversation.com/files/523912/original/file-20230502-24-94zt8j.jpg?ixlib=rb-1.1.0&rect=18%2C37%2C4174%2C2992&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The knife easily leaves swirls in the spread.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/peanut-butter-on-bread-royalty-free-image/525694555">rimglow/iStock via Getty Images Plus</a></span></figcaption></figure><p>Those Transportation Security Administration requirements are drilled into every frequent flyer’s head: You can carry on liquids that are only less than 3.4 ounces (100 milliliters) in volume each.</p>
<p>But when the TSA recently <a href="https://www.nytimes.com/2023/03/20/travel/tsa-peanut-butter-liquid-security.html">confiscated a jar of Jif</a> under this rule, peanut butter lovers were up in arms. Some skeptics of security may suspect hungry officers just wanted to make their own PB&Js. TSA, however, contends that peanut butter is a liquid – and a full-size jar of Jif is over the 3.4-ounce limit.</p>
<p>Just like Americans’ favorite <a href="https://www.britannica.com/plant/peanut">legume-based sandwich ingredient</a>, the story – and the outrage it inspired – began to spread. However, I’m a <a href="https://scholar.google.com/citations?user=a_wXzfUAAAAJ&hl=en&oi=ao">mechanical engineer who studies fluid flows</a>, and the TSA action made sense to me. By the scientific definition, peanut butter is indeed a liquid.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/Cp31MElLPb6","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>First consider fluids</h2>
<p>To define a liquid, we must first <a href="https://www.britannica.com/science/fluid-physics">define a fluid</a>. Any material that flows continuously when a shearing force is applied is a fluid. Think of a shearing force as a cutting action through a substance that causes it to flow continuously. For example, moving your arm causes the surrounding air to change shape – or deform, to use the physics term – and flow out of the way. The same thing happens to water when your arm takes a swim stroke.</p>
<p>There are many kinds of fluids. Some act very predictably and move smoothly, as air or water do. These are called <a href="https://www.sciencedirect.com/topics/engineering/newtonian-fluid">Newtonian fluids</a>, named after Sir Isaac Newton. Scientifically, a Newtonian fluid is one in which the shear force varies in direct proportion with the stress it puts on the material, known as the shearing strain. For a Newtonian fluid, the resistance to fluid flow – that is, its viscosity – is constant at a given temperature.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="boxes with arrows showing force pushing in opposite directions on top and bottom edge" src="https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=194&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=194&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=194&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=243&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=243&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524115/original/file-20230503-20-1s0oz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=243&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Shearing forces push a material in opposite directions, producing shearing strain.</span>
<span class="attribution"><a class="source" href="https://www.designingbuildings.co.uk/wiki/File:Shear.jpg">Designing Buildings</a></span>
</figcaption>
</figure>
<p>Other types of fluids do not move quite as smoothly and easily. For some, like peanut butter, a minimum shearing or cutting force may be needed to get it flowing, and it may vary nonlinearly with shearing strain. Imagine you’re stirring a jar of peanut butter. If you stir really fast, with more shearing force, the PB gets runnier, while if you stir slowly the PB remains stiff. These types of fluids are called non-Newtonian fluids. Peanut butter may stick more than flow – maybe you could consider this movement more chunky-style. </p>
<p>Peanut butter is actually a great example of a non-Newtonian fluid because it doesn’t flow as easily as air or water but will flow if sufficient force is applied, such as when a knife spreads it on bread. How easily it flows will also depend on temperature – you may have experienced peanut butter drips after slathering it on warm toast.</p>
<h2>Strange fluids are all around us</h2>
<p>Our everyday lives – but not our airplane carry-ons – are filled with substances that are unexpected fluids. In general, if it can flow, it’s a fluid. And it will eventually take the shape of its container.</p>
<p>Some surprising fluids are peanut butter’s kitchen neighbors, like whipped cream, mayonnaise and cookie batter. You’ll find others in the bathroom, like toothpaste. The natural world is home to other strange fluids, like <a href="https://theconversation.com/lava-ash-flows-mudslides-and-nasty-gases-good-reasons-to-respect-volcanoes-96260">lava</a>, <a href="https://theconversation.com/deadly-california-mudslides-show-the-need-for-maps-and-zoning-that-better-reflect-landslide-risk-90087">mudslides</a>, avalanches and quicksand.</p>
<p>Gravel can be considered fluidlike. The individual particles are solids, but a collection of gravel particles can be poured and fill a container – its what’s called a granular fluid, because it has fluidlike properties. The same can be said for cereal poured out of a box or sugar into a bowl.</p>
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<a href="https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="squirrel lying flat on a beam" src="https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=594&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=594&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=594&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=747&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=747&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523882/original/file-20230502-24-6afuch.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=747&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The body of a fully relaxed squirrel counts as a fluid, flowing to fill its container.</span>
<span class="attribution"><span class="source">Ted Heindel</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Traffic flows on a busy highway, and people flow out of a crowded sporting venue.</p>
<p>You could even consider a <a href="https://theconversation.com/answering-the-question-that-won-me-the-ig-nobel-prize-are-cats-liquid-86589">cat lying in the sun to be a fluid</a> when it has flattened out and fills its containerlike skin. Sleepy, relaxed dogs, squirrels and even zonked-out babies can meet the definition of a fluid.</p>
<h2>Liquids are one type of fluid</h2>
<p>Now, you might be objecting: But, the TSA didn’t call peanut butter a fluid, they said it’s a liquid!</p>
<p>Fluids are divided into two general categories: gases and liquids. Both gases and liquids can be deformed and poured into containers and will take the shape of their container. But gases can be compressed, while liquids cannot, at least not easily.</p>
<p>Peanut butter can be poured into its container and then it deforms, or takes the shape of that container. And every 5-year-old knows that peanut butter does not compress. When they squish their PB&J or peanut butter crackers together, the peanut butter does not smoosh into a smaller volume. No – it squirts out the sides and onto their hands.</p>
<p>So, the verdict on peanut butter: delicious liquid.</p>
<p>If you plan to make a PB&J sandwich midflight, count on bringing less than 3.4 ounces of liquid peanut butter. And the same goes for its liquid cousin, jelly.</p><img src="https://counter.theconversation.com/content/203716/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ted Heindel does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A mechanical engineer explains why you need to go with the flow. The TSA pronouncement that peanut butter is a liquid is scientifically sound.Ted Heindel, University Professor, Bergles Professor of Thermal Science, and Director of the Center for Multiphase Flow Research and Education, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1233332019-10-01T12:28:46Z2019-10-01T12:28:46ZA father-physician tests if a little peanut a day keeps allergy away<figure><img src="https://images.theconversation.com/files/293297/original/file-20190919-22450-18ijms5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Creamy and smooth peanut butter and peanuts can trigger deadly reactions in those with allergies.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/creamy-smooth-peanut-butter-jar-on-316086323">inewsfoto/Shutterstock.com</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>No one I knew had food allergy, let alone peanut allergy, when I was a child. I grew up at a time when peanuts were given freely on airplanes, and there was no such thing as a peanut-free table at school. Fast forward to today and the world has changed, with food allergies taking on almost <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=Food+Allergy%3A+An+Enigmatic+Epidemic">epidemic-like proportions</a>. </p>
<p>I am an allergist and became interested in food allergies in 2004 after spending a month working with Dr. Wesley Burks, one of the world’s leaders in food allergy research, at the Duke Allergy Clinic. I was fascinated that a simple peanut could cause the immune system to go haywire. That knowledge inspired me to spend the next six years of medical training learning as much as I could about what triggered food allergies and how to treat them. This paid off in 2011 when I was invited to join the allergy faculty at the University of North Carolina. Just as I was getting settled into my new life as a doctor and researcher for food allergy, my world changed again. </p>
<p>On a Monday morning in September 2013, I gave my nine-month-old son Elliott peanut butter on toast for the first time, and then it happened. He had a severe allergic reaction: head-to-toe rash, vomiting and coughing. Suddenly food allergy was real to me in a way I could not have ever imagined.</p>
<p>Like many other parents, my first emotion was denial. When I finally accepted that he was now one of the estimated <a href="http://doi.org/10.1542/peds.2018-1235">1.6 million kids in the U.S. who have peanut allergy</a>, I hoped he would just outgrow it. Unfortunately, for peanut allergy, almost 80% of peanut-allergic kids <a href="http://doi.org/10.1016/j.jaci.2015.01.002">hang on to it for life</a>. So just as I had advised many families at my allergy clinic, I went to the pharmacy to get our EpiPen and reentered the world hoping to never have to use it.</p>
<p>Professionally, things have changed for me as well. I’ve spent the last 10 years trying to develop a therapy that can protect kids with food allergies from having severe allergic reactions or even dying. Finally, after years of testing in clinical trials, I’m hopeful that small drops of a peanut solution may bring us one step closer to making this a reality.</p>
<h2>Trying to find a cure</h2>
<p>Immunotherapy for peanut allergy works by exposing the child to small, increasing amounts of peanut each day to retrain the immune system and make it less reactive. There are a few types of immunotherapy that differ based on how the child is exposed. Oral immunotherapy uses lightly roasted peanut flour that must be eaten. What’s called epicutaneous immunotherapy is administered using a “<a href="https://www.mdmag.com/conference-coverage/aaaai-2019/mixed-results-peanut-allergy-immunotherapy-patch-trial">peanut patch</a>” that is absorbed through the skin. Sublingual immunotherapy uses liquid peanut drops that are absorbed through the mouth.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293300/original/file-20190919-22429-fsm9f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mylan generic packaging of two EpiPen auto-injectors used for treatment of allergic reactions.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/saint-louis-united-states-october-18-739551895?src=NEntoTXnzVmnAzK0BOInaA-1-7">Amy Kerkemeyer</a></span>
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<p>Over the past 10 years, multiple studies have shown that oral immunotherapy using peanut flour can work. The Aimmune Therapeutics company completed the largest peanut <a href="http://doi.org/10.1056/NEJMoa1812856">oral immunotherapy study</a> in the world. Also during the last decade, DBV Technologies developed its unique peanut patch and completed a <a href="http://doi.org/10.1001/jama.2019.1113">multinational study of hundreds of peanut-allergic kids</a>. (Disclosure: I consult for both of the companies that sponsored the studies.)</p>
<p>The Aimmune Therapeutics study of the oral treatment showed that the peanut flour protected 67% of the allergic kids from having allergic reactions after eating up to three and a half peanuts. Before starting treatment, less than one-third of a peanut would have triggered a reaction. But actually taking the peanut flour treatment required special timing and preparation that made it hard for some of the families. In addition, side effects like rash, stomach aches and vomiting prevented 12% of the kids from completing the treatment. </p>
<p>In contrast, the DBV peanut patch study showed that sticking the patch to the skin once a day was simple, with over 98% of patches successfully applied. The patch caused some redness, but only 2% of the kids had to stop the treatment early. However, only 35% of the kids seemed to benefit from the patch, and they were able to tolerate only one and a half peanuts.</p>
<h2>A new option for peanut allergy</h2>
<p>At UNC, my colleagues and I have been developing an alternative treatment called sublingual immunotherapy, or SLIT for short, using liquid peanut drops that are taken under the tongue. <a href="http://doi.org/10.1016/j.jaci.2019.07.030">In our recently published long-term study of peanut SLIT</a>, kids put two milligrams of peanut solution – about 1/150th of a peanut – under their tongue for two minutes daily. They continued this therapy for between three and five years, and afterwards almost 70% of the kids were able to safely eat two and half peanuts without suffering an allergic reaction. These drops have been tested by a <a href="http://doi.org/10.1016/j.jaci.2014.12.1917">multi-center NIH group</a> – called CoFAR – and a study directly <a href="http://doi.org/10.1016/j.jaci.2014.11.005">comparing the drops with the peanut flour</a> was done at Johns Hopkins. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293962/original/file-20190925-51463-iuniq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Elliott embarks upon a safe and happy Halloween. He is not actually on any of the described treatments at this time.</span>
</figcaption>
</figure>
<p>This is at least 10 times the quantity it would take to trigger an allergic response to an accidental peanut. One-quarter of the kids in our trial finished the entire test, which involved consuming the equivalent of 17 peanuts, without any symptoms at all. About 5% of the more than 75,000 doses caused side effects, but most of them were just itching in the mouth that went away on its own. Thankfully, none of the kids needed epinephrine to treat any side effects. </p>
<p>Peanut allergy is not the end of the world, but it is life-changing. My son Elliott does not want to eat peanuts, but he does want to sit with his friends at lunch and eat that birthday cake at the party and go trick-or-treating with all the other kids. </p>
<p>It is exciting that after all this time, treatments are coming. Whether it’s peanut flour or the patch, or now possibly our liquid peanut SLIT drops, he may soon be able to do these things without worrying, just like all the other kids.</p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/123333/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edwin Kim receives research funding from NIH, FARE, and the Wallace Foundation. He consults for Aimmune Therapeutics, DBV Technologies, Allakos, AllerGenis, Ukko and Vibrant America.</span></em></p>There’s a new therapy for treating peanut allergy that is showing promise in phase 3 trials.Edwin Kim, Assistant Professor of Medicine and Pediatrics and Director of the UNC Food Allergy Initiative, University of North Carolina at Chapel HillLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/866492017-11-02T17:27:06Z2017-11-02T17:27:06ZIn America’s sandwiches, the story of a nation<figure><img src="https://images.theconversation.com/files/193075/original/file-20171102-26483-ais8mr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/roast-beef-sandwich-on-plate-pickles-675902929?src=dhOfZe0q8WbQgSGvfCnEXw-1-41">Anna_Pustynnikova</a></span></figcaption></figure><p><em>Everyone has a favorite sandwich, often prepared to an exacting degree of specification: Turkey or ham? Grilled or toasted? Mayo or mustard? White or whole wheat?</em> </p>
<p><em>We reached out to five food historians and asked them to tell the story of a sandwich of their choosing. The responses included staples like peanut butter and jelly, as well as regional fare like New England’s chow mein sandwich.</em> </p>
<p><em>Together, they show how the sandwiches we eat (or used to eat) do more than fill us up during our lunch breaks. In their stories are themes of immigration and globalization, of class and gender, and of resourcefulness and creativity.</em></p>
<hr>
<h2>A taste of home for working women</h2>
<p><strong>Megan Elias, Boston University</strong></p>
<p>The tuna salad sandwich originated from an impulse to conserve, only to become a symbol of excess. </p>
<p>In the 19th century – before the era of supermarkets and cheap groceries – most Americans avoided wasting food. Scraps of chicken, ham or fish from supper would be mixed with mayonnaise and served on lettuce for lunch. Leftovers of celery, pickles and olives – served as supper “relishes” – would also be folded into the mix. </p>
<p>The versions of these salads that incorporated fish tended to use salmon, white fish or trout. Most Americans didn’t cook (or even know of) tuna. </p>
<p>Around the end of the 19th century, middle-class women <a href="https://www.penguinrandomhouse.com/books/98859/land-of-desire-by-william-r-leach/9780679754114/">began to spend more time in public</a>, patronizing department stores, lectures and museums. Since social conventions kept these women out of the saloons where men ate, lunch restaurants opened up to cater to this new clientele. They offered women exactly the kind of foods they had served each other at home: salads. While salads made at home often were composed of leftovers, those at lunch restaurants were made from scratch. Fish and shellfish salads were typical fare. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=841&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=841&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=841&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1057&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1057&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193068/original/file-20171102-26483-15wim46.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1057&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A 1949 ad in Ladies’ Home Journal announces a ‘Revolution in Tuna.’</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/c/c0/The_Ladies%27_home_journal_%281948%29_%2814766583732%29.jpg">Internet Archive Book Images</a></span>
</figcaption>
</figure>
<p>When further social and economic changes <a href="https://global.oup.com/academic/product/out-to-work-9780195157093?cc=us&lang=en&">brought women into the public as office and department store workers</a>, they found fish salads waiting for them at the affordable lunch counters patronized by busy urban workers. Unlike the ladies’ lunch, the office lunch hour had time limits. So lunch counters came up with the idea of offering the salads between two pieces of bread, which sped up table turnover and encouraged patrons to get lunch to go. </p>
<p><a href="https://www.ucpress.edu/book.php?isbn=9780520261846">When canned tuna was introduced in the early 20th century</a>, lunch counters and home cooks could skip the step of cooking a fish and go straight to the salad. But there was downside: The immense popularity of canned tuna led to the growth of a global industry that has severely depleted stocks and led to the unintended <a href="https://swfsc.noaa.gov/textblock.aspx?Division=PRD&ParentMenuId=228&id=1408">slaughter of millions of dolphins</a>. A clever way to use dinner scraps has become a global crisis of conscience and capitalism. </p>
<p>I like mine on toasted rye.</p>
<hr>
<h2>East meets West in Fall River, Massachusetts</h2>
<p><strong>Imogene Lim, Vancouver Island University</strong></p>
<p>“Gonna get a big dish of beef chow mein,” Warren Zevon <a href="https://play.google.com/music/preview/Tzmgsphpess3y2zc3oglxr4aira?lyrics=1&utm_source=google&utm_medium=search&utm_campaign=lyrics&pcampaignid=kp-lyrics&u=0#">sings</a> in his 1978 hit “Werewolves of London,” a nod to the popular Chinese stir-fried noodle dish. </p>
<p>During that same decade, <a href="https://folklife.si.edu/talkstory/2015/songs-for-ourselves-an-asian-american-music-playlist">Alika and the Happy Samoans</a>, the house band for a Chinese restaurant in Fall River, Massachusetts, also paid tribute to chow mein with a song titled “<a href="https://soundcloud.com/moyamoya4201/alika-and-the-happy-samoans">Chow Mein Sandwich</a>.”</p>
<p>Chow mein in a sandwich? Is that a real thing?</p>
<p>I was first introduced to the chow mein sandwich while completing my doctorate at Brown University. Even as the child of a Chinatown restaurateur from Vancouver, I viewed the sandwich as something of a mystery. It led to a post-doctoral fellowship and <a href="http://wordpress.viu.ca/limi/files/2012/07/ChowMeinSandwiches1994o.pdf">a paper</a> about Chinese entrepreneurship in New England. </p>
<p>The chow mein sandwich is the quintessential “East meets West” food, and it’s largely associated with New England’s Chinese restaurants – specifically, those of Fall River, a city crowded with textile mills near the Rhode Island border. </p>
<p>The sandwich became popular in the 1920s because it was filling and cheap: Workers munched on them in factory canteens, while their kids ate them for lunch in the parish schools, especially on meatless Fridays. It would go on to be available at some “five and dime” lunch counters, like <a href="http://www.enterprisenews.com/news/20160407/lunch-counter-memories-at-kresges-department-store-in-brockton">Kresge’s</a> and <a href="http://www.nytimes.com/1997/07/18/business/woolworth-gives-up-on-the-five-and-dime.html">Woolworth</a> – and even at <a href="http://photobucket.com/gallery/http://s143.photobucket.com/user/genalof/media/BLOG/09BLOG-6.jpg.html">Nathan’s</a> in Coney Island.</p>
<p>It’s exactly what it sounds like: a sandwich filled with chow mein (deep-fried, flat noodles, topped with a ladle of brown gravy, onions, celery and bean sprouts). If you want to make your own authentic sandwich at home, I recommend using <a href="https://www.famousfoods.com/newengland-chow.html">Hoo Mee Chow Mein Mix</a>, which is still made in Fall River. It can be served in a bun (à la sloppy joe) or between sliced white bread, much like a hot turkey sandwich with gravy. The classic meal includes the sandwich, french fries and orange soda.</p>
<p>For those who grew up in the Fall River area, the chow mein sandwich is a reminder of home. Just ask famous chef (and Fall River native) Emeril Lagasse, who came up with his own “Fall River chow mein” <a href="https://www.splendidtable.org/recipes/fall-river-chow-mein">recipe</a>. </p>
<p>And at one time, Fall River expats living in Los Angeles would hold a “Fall River Day.” </p>
<p>On the menu? Chow mein sandwiches, of course. </p>
<hr>
<h2>A snack for the elites</h2>
<p><strong>Paul Freedman, Yale University</strong></p>
<p>Unlike many American food trends of the 1890s, such as the Waldorf salad and <a href="http://collections.vam.ac.uk/item/O93019/chafing-dish-cover-benson-william-arthur/">chafing dishes</a>, the club sandwich has endured, immune to obsolescence. </p>
<p>The sandwich originated in the country’s stuffy gentlemen’s clubs, which are known – to this day – for a conservatism that includes loyalty to outdated cuisine. (The Wilmington Club in Delaware continues to serve <a href="https://www.saveur.com/history-of-turtle-soup-hunting">terrapin</a>, while the Philadelphia Club’s specialties include veal and ham pie.) So the club sandwich’s spread to the rest of the population, along with its lasting popularity, is a testament to its inventiveness and appeal. </p>
<p>A two-layer affair, the club sandwich calls for three pieces of toasted bread spread with mayonnaise and filled with chicken or turkey, bacon, lettuce and tomato. Usually the sandwich is cut into two triangles and held together with a toothpick stuck in each half. </p>
<p>Some believe it should be eaten with a fork and knife, and its blend of elegance and blandness make the club sandwich a permanent feature of country and city club cuisine.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193071/original/file-20171102-26448-193bmll.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The club sandwich: A perfect blend of elegance and blandness.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/club-sandwich-on-rustic-wooden-background-188159096">Alena Haurylik</a></span>
</figcaption>
</figure>
<p><a href="http://www.theoldfoodie.com/2015/11/the-evolution-of-club-sandwich.html">As far back as 1889</a>, there are references to a Union Club sandwich of turkey or ham on toast. The Saratoga Club-House offered a club sandwich on its menu beginning in 1894. </p>
<p>Interestingly, until the 1920s, sandwiches were identified with ladies’ lunch places that served “dainty” food. The first club sandwich recipe comes from an 1899 book of “salads, sandwiches and chafing-dish dainties,” and <a href="http://www.cntraveller.com/news/2012/january/in-praise-of-the-club-sandwich">its most famous proponent</a> was Wallis Simpson, the American woman whom Edward VIII abdicated the throne of Great Britain <a href="https://www.vanityfair.com/style/2016/11/edward-viii-wallis-simpson-wedding-photos-auction">to marry</a>. </p>
<p>Nonetheless, an 1889 article from the New York Sun entitled “An Appetizing Sandwich: A Dainty Treat That Has Made a New York Chef Popular” describes the Union Club sandwich as appropriate for a post-theater supper, or something light to be eaten before a nightcap. This was one type of sandwich that men could indulge in, the article seemed to be saying – as long as it wasn’t eaten for lunch.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193059/original/file-20171102-26462-1mm46ms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">New York City’s Union Club served an early version of the club sandwich that was a hit.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/5/59/Union_Club_NYC_003.JPG">Gryffindor</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<h2>‘The combination is delicious and original’</h2>
<p><strong>Ken Albala, University of the Pacific</strong></p>
<p>While the peanut butter and jelly sandwich eventually became a staple of elementary school cafeterias, it actually has upper-crust origins.</p>
<p>In the late-19th century, at elegant ladies’ luncheons, a popular snack was small, crustless tea sandwiches with butter and cucumber, cold cuts or cheese. Around this time, health food advocates like John Harvey Kellogg <a href="https://books.google.com/books?id=4UkSAAAAYAAJ&pg=PA140&dq=peanut+butter+inauthor:John+inauthor:Harvey+inauthor:Kellogg&hl=en&sa=X&ved=0ahUKEwiiuKHl953XAhUT5GMKHQe7A3MQ6AEIMzAC#v=onepage&q=peanut%20butter%20inauthor%3AJohn%20inauthor%3AHarvey%20inauthor%3AKellogg&f=false">started promoting</a> peanut products as a replacement for animal-based foods (butter included). So for a vegetarian option at these luncheons, peanut butter simply replaced regular butter.</p>
<p>One of the earliest known recipes that suggested including jelly with peanut butter appeared in a 1901 issue of the Boston Cooking School Magazine. </p>
<p>“For variety,” author Julia Davis Chandler <a href="https://books.google.com/books?id=diUjAQAAIAAJ&dq=%22some%20day%20try%20making%20little%20sandwiches%2C%20or%20bread%20fingers%2C%20of%20three%20very%20thin%20layers%20of%20bread%20and%20two%20of%20filling%2C%20one%20of%20peanut%20paste&pg=RA1-PA188#v=onepage&q&f=false">wrote</a>, “some day try making little sandwiches, or bread fingers, of three very thin layers of bread and two of filling, one of peanut paste, whatever brand you prefer, and currant or crabapple jelly for the other. The combination is delicious, and so far as I know original.”</p>
<p>The sandwich moved from garden parties to lunchboxes in the 1920s, when peanut butter started to be mass produced with hydrogenated vegetable oil and sugar. Marketers of the Skippy brand targeted children as a potential new audience, and thus the association with school lunches was forged. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IPDH87kq-6M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A Skippy peanut butter television ad from 1986.</span></figcaption>
</figure>
<p>The classic version of the sandwich is made with soft, sliced white bread, creamy or chunky peanut butter and jelly. Outside of the United States, the peanut butter and jelly sandwich <a href="https://www.huffingtonpost.com/2014/04/09/peanut-butter_n_5105203.html">is rare </a> – much of the world views the combination as repulsive. </p>
<p>These days, many try to avoid <a href="https://www.salon.com/2012/03/03/the_rise_and_fall_of_white_bread/">white bread</a> and <a href="http://www.latimes.com/food/dailydish/la-dd-rise-and-fall-of-trans-fat-20131107-story.html">hydrogenated fats</a>. Nonetheless, the sandwich has a nostalgic appeal for many Americans, and recipes for <a href="https://www.vogue.com/article/food-sqirl-recipe-peanut-butter-and-jelly-sandwich-jam">high-end versions</a> – with freshly ground peanuts, artisanal bread or unusual jams – <a href="http://www.thecheapgourmet.com/2007/08/gourmet-peanut-.html">now circulate on the web</a>. </p>
<hr>
<h2>The Daughters of the Confederacy get creative</h2>
<p><strong>Andrew P. Haley, University of Southern Mississippi</strong></p>
<p>The <a href="https://en.wikipedia.org/wiki/Scotch_woodcock">Scotch woodcock</a> is probably not Scottish. It’s arguably not even a sandwich. A favorite of Oxford students and members of Parliament until the mid-20th century, the dish is generally prepared by layering anchovy paste and eggs on toast.</p>
<p>Like its cheesier cousin, the Welsh rabbit (better known as rarebit), its name is fanciful. Perhaps there was something about the name, if not the ingredients, that sparked the imagination of Miss Frances Lusk of Jackson, Mississippi.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=751&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=751&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=751&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193072/original/file-20171102-26448-lh4msg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The United Daughters of the Confederacy cookbook features a take on the Scotch woodcock.</span>
<span class="attribution"><a class="source" href="http://digilib.usm.edu/cdm/compoundobject/collection/missana/id/1279/show/1254">McCain Library and Archives, The University of Southern Mississippi</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Inspired to add a little British sophistication to her entertaining, she crafted <a href="http://digilib.usm.edu/cdm/ref/collection/missana/id/1268">her own version</a> of the Scotch woodcock for a 1911 United Daughters of the Confederacy fundraising cookbook. Miss Lusk’s woodcock sandwich mixed strained tomatoes and melted cheese, added raw eggs, and slathered the paste between layers of bread (or biscuits). </p>
<p>As food historian Bee Wilson argues in her <a href="https://books.google.com/books?id=ydR5na_9fnYC&lpg=PP1&dq=bee%20wilson%20sandwich&pg=PP1#v=onepage&q&f=false">history of the sandwich</a>, American sandwiches distinguished themselves from their British counterparts by the scale of their ambition. Imitating the rising skylines of American cities, many were towering affairs that celebrated abundance. </p>
<p>But those sandwiches were the sandwiches of <a href="https://restaurant-ingthroughhistory.com/2014/01/19/early-chains-baltimore-dairy-lunch/">urban lunchrooms</a> and, later, diners. In the homes of southern clubwomen, the sandwich was a way to marry British sophistication to American creativity.</p>
<p>For example, the United Daughters of the Confederacy cookbook included “sweetbread sandwiches,” made by heating canned <a href="https://www.merriam-webster.com/dictionary/offal">offal</a> (animal trimmings) and slathering the mashed mixture between two pieces of toast. There’s also a “green pepper sandwich,” crafted from “very thin” slices of bread and “very thin” slices of green pepper. </p>
<p>Such creative combinations weren’t limited to the elites of Mississippi’s capital city. In the plantation homes of the Mississippi Delta, members of the Coahoma Woman’s Club served sandwiches of English walnuts, black walnuts and stuffed olives ground into a colorful paste. They also assembled “Friendship Sandwiches” from grated cucumbers, onions, celery and green peppers mixed with cottage cheese and mayonnaise. Meanwhile, the industrial elite of Laurel, Mississippi, served <a href="http://digilib.usm.edu/cdm/ref/collection/missana/id/1351">mashed bacon and eggs sandwiches</a> and <a href="http://digilib.usm.edu/cdm/ref/collection/missana/id/1351">creamed sardine sandwiches</a>.</p>
<p>Not all of these amalgamations were capped by a slice of bread, so purists might balk at calling them sandwiches. But these ladies did – and they proudly tied up their original creations with ribbons.</p><img src="https://counter.theconversation.com/content/86649/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Five food experts peer under the bread to plumb the histories of the country’s unique sandwiches, from favorites like tuna fish to lesser-known fare like the woodcock.Paul Freedman, Chester D. Tripp Professor of History, Yale UniversityAndrew P. Haley, Associate Professor of American Cultural History, The University of Southern MississippiImogene L. Lim, Professor of Anthropology, Vancouver Island UniversityKen Albala, Professor of History, University of the PacificMegan Elias, Associate Professor of the Practice of Gastronomy, Boston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/369012015-02-18T03:32:22Z2015-02-18T03:32:22ZPeanut allergy treatment is on the horizon – but don’t drop the EpiPen yet<figure><img src="https://images.theconversation.com/files/71919/original/image-20150213-13206-vlgpy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Avoiding peanuts is currently the only way to prevent allergic reactions.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/sharynmorrow/3052699217/in/photolist-5DKT88-53Sm9N-oNomHQ-oNoo2w-93xAGy-62u7wG-bWEvKe-dVMqvf-2nqmq8-9rPN4e-79pjrS-ayw5N5-4E6e8S-niRBmL-4U4cfX-8gHzoq-7vRdJJ-ovW44e-oNonnL-5ihiFa-6AFQ19-niRAHm-7nhGAz-6YVE6n-9nn7Ax-8sQHCK-piZE4i-9VU913-5a4478-5V4V9Z-8JXJrn-NBgcU-5Ubhzm-4wcgcQ-6UC8Tv-4nx5uY-dUtSCJ-bGhKLH-PvRcS-eb9ZMt-b9fM8r-ecj1x-6p5Sor-biKrZ4-6oMbCY-7ADVx8-7mg64d-93uuMp-dYA1YH-AyLw7">sharyn morrow/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Rates of food allergies have increased over recent decades and are at an all-time high. While we don’t know the full extent of the allergy epidemic, the <a href="http://www.ncbi.nlm.nih.gov/pubmed/19217654">rate of hospitalisation</a> for food allergies has quadrupled since the mid-90s.</p>
<p>Peanuts are one of the most common causes of food allergies. The <a href="https://www.mcri.edu.au/research/projects/healthnuts">HealthNuts study</a> tested almost 3,000 Melbourne children born between 2006 and 2009 and found 3% of infants had a confirmed peanut allergy. Only one in five children had grown out of the allergy by four years of age. </p>
<p>Researchers have made some promising steps forward in developing a treatment for peanut allergies, but there is currently no cure. Avoiding the food is the only way to prevent allergic reactions.</p>
<h2>What is a peanut allergy?</h2>
<p>Peanut allergies occur when the body’s immune system develops antibodies – called immunoglobulin (Ig) E molecules – against parts of the “harmless” peanut protein. This is known as sensitisation.</p>
<p>Sensitisation can be easily detected by measuring peanut-specific immunoglobulin E either in the child’s blood or by means of a skin prick test.</p>
<p>Allergy as a disease is seen when IgE antibodies activate the immune system. This may lead to face, lip, eye swelling, welts and hives, breathing difficulties, vomiting, and even collapse of the body’s blood circulation. </p>
<p>The most severe form of reaction, anaphylaxis, can cause swelling of the tongue and throat. This is a potentially life-threatening condition that requires emergency treatment with adrenalin autoinjectors (also known by the brand name, EpiPen).</p>
<p>But not everybody who has IgE antibodies to “peanut” will experience an allergic reaction. </p>
<p>Sometimes peanut sensitisation is found in a child who has never been exposed to peanuts. This is more common in children with eczema or children who have other food allergies. </p>
<p>In other cases, the symptoms cannot be unequivocally attributed to allergy and/or exposure to peanut. In these situations, the question has to be resolved: is it “only” peanut sensitisation or is it a peanut allergy?</p>
<h2>Causes</h2>
<p>The causes of sensitisation are unknown but <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa013536">research suggests</a> it could occur through the skin in children with eczema. </p>
<p>Other factors affecting this meteoric rise <a href="http://fooddrugallergy.ucla.edu/body.cfm?id=40">could be</a> cleaner and more hygienic environments and the delayed introduction of allergenic foods.</p>
<h2>Diagnosis</h2>
<p>If a patient presents with symptoms of allergic reaction after eating peanuts, a positive skin prick test to peanuts or detecting the presence of specific IgE to peanuts by a blood test, will confirm the peanut allergy.</p>
<p>However, if the history is ambiguous or sensitisation is seen in the absence of a known exposure to peanut, the patient may need to undergo a food challenge to confirm the peanut allergy. As this could lead to an allergic reaction, food challenges need to be performed in a clinical setting, where treatment is readily available. </p>
<p>Our <a href="http://onlinelibrary.wiley.com/doi/10.1111/cea.12258/abstract">Newcastle Peanut Anaphylaxis Predictors study</a> showed that the combination of an antibody test and a breathing test that measures a molecule called nitric oxide in exhaled air can avoid the need for a food challenge test in half of the children suspected to have peanut allergy. </p>
<p>Building on this approach, we have developed a blood test to predict anaphylaxis, which is currently being validated in a large population of children with suspected peanut allergy. </p>
<h2>Treatment</h2>
<p>Most children with peanut allergy need to carry an adrenaline autoinjector because it provides immediate relief from severe allergic reactions. </p>
<p>The uncertainty of when a severe reaction will occur places immense psychological and social burdens on patients and families. As a consequence, a number of children with peanut allergy <a href="http://onlinelibrary.wiley.com/store/10.1111/j.1398-9995.2010.02342.x/asset/j.1398-9995.2010.02342.x.pdf;jsessionid=640A3E4F5E182E01F3BDCB58DAAF21A7.f02t04?v=1&t=i636xo7b&s=b60f3b06bed2c02a7304baf21005e2ac22f32ece">suffer from</a> anxiety-based disorders. </p>
<p>Encouragingly, researchers have recently made progress in optimising immunotherapy, also called peanut “desensitisation”. In this process small amounts of peanut protein is administered regularly to build up “tolerance” to the food.</p>
<p>British scientists Leonard Noon and John Freeman were the first to show in 1911 that desensitisation to pollen could be an effective treatment for hay fever. </p>
<p>A century later, a <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3060783/">study</a> with 28 children in Durham, North Carolina, showed that oral immunotherapy could reduce allergic reactions to peanut. </p>
<p>This study was subsequently confirmed by the <a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2813%2962301-6/abstract">STOP II trial</a> in Cambridge, UK where 62% of children with peanut allergy were able to eat five to ten peanuts without allergy symptoms six months after the initiation of treatment. </p>
<p>Recently, Professor Mimi Tang and co-workers from the Murdoch Childrens Research Institute, Melbourne, <a href="http://www.theatlantic.com/health/archive/2015/01/a-possible-treatment-for-peanut-allergies/385045/">studied</a> an oral probiotic peanut combination immunotherapy in 62 allergic children without previous anaphylaxis. Children enrolled in this study were regularly given small amounts of a peanut and probiotic combination so as to develop tolerance to peanut.</p>
<p>This treatment resulted in 82% of children being “tolerant” to peanuts, meaning they were able to eat roughly 20 to 40 peanuts without allergy symptoms, two to five weeks after the treatment stopped. This suggests that there may be a treatment in the future, which has a sustained effect. </p>
<p>However, treatment side-effects with oral peanut (and probiotic combination) immunotherapy are very common, with 45% to 93% of children affected. That’s why oral peanut immunotherapy can only be provided within high-level specialist care and at present is advisable to do only within research settings.</p>
<p>In future, we hope to be able to use bio-markers to predict whether children who come into contact with peanuts will have anaphylaxis and whether they’ll respond to different treatments.</p><img src="https://counter.theconversation.com/content/36901/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rani Bhatia has received funding from Hunter Children's Research Foundation. She is an inventor on a provisional patent that describes a marker for peanut allergy </span></em></p><p class="fine-print"><em><span>Adam Collison receives funding from Hunter Children's Research Foundation and the Thrasher Research Fund. He is an inventor on a provisional patent that describes a marker for peanut allergy.</span></em></p><p class="fine-print"><em><span>Joerg Mattes receives/has received funding from the NHMRC, Hunter Medical Research Institute, Asthma Australia and the CRC for Asthma. He is an inventor on a provisional patent that describes a marker for peanut allergy.</span></em></p>Rates of food allergies have increased over recent decades and are at an all-time high. While we don’t know the full extent of the allergy epidemic, the rate of hospitalisation for food allergies has quadrupled…Rani Bhatia, Senior Staff Specialist in Paediatric Allergy and Immunology at John Hunter Children's Hospital Newcastle NSW Conjoint Lecturer in Paediatrics, University of NewcastleAdam Collison, Post Doctoral researcher - Experimental and Translational Respiratory Medicine Research Group, University of NewcastleJoerg Mattes, Professor&Chair of Paediatrics | HMRI, University of Newcastle, Australia | Senior Staff Specialist Paediatric Respiratory&Sleep Medicine | John Hunter Children's Hospital, Australia, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.