[00:00] Would you like some good news about the  United States? Peanut allergies, which are   among the most dramatic and dangerous of all food  allergies — peanut allergies are plummeting. Like,  
[00:20] the rate of new peanut allergies among little kids  has dropped nearly in half over the last decade.   This is according to a big new study  from Children's Hospital of Philadelphia.
[00:34] Why? How? Well, apparently, because public  health awareness campaigns actually work.  
[00:47] Because the public health bureaucracy, which  the present U.S. administration has set on   fire — the public health bureaucracy  actually works, at least sometimes.
[01:04] Scientists found that feeding peanuts  to babies and toddlers makes them much   less likely to develop peanut allergy later in  life, and public health professionals worked to  
[01:19] inform people of this fact. Their efforts  are now bearing fruit. Or nuts. Or beans,   actually. Peanuts are technically beans.  Which are technically fruits. Actually  
[01:36] they're the seeds of fruits. Which  is also what nuts are, but anyway. We're gonna cover this new research and  the older research on which it is based.  
[01:48] And we'll try to answer some basic questions  about peanut allergies, including why they only   seem to be prevalent in rich countries. Also,  what even is an allergy? Let's start there.
[02:06] Actually let's start by thanking the sponsor  of this video, Create creatine gummies.   You know that I generally avoid advertising  health-related products in health-related videos,   but ethically, I feel fine doing it in  this case because I'm advertising creatine,  
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[04:10] including subscriptions. 30% off with my  link in the description. Thank you, Create. Anyway, peanut allergies. What even is an allergy?
[04:22] An allergy is your own immune system hurting you  because it mistakenly freaks out over a harmless   substance that you encounter. This is true of  all allergies, food allergies or otherwise.
[04:41] Like many people, I am allergic to some kinds of  pollen — the airborne, powdery sperm of flowers.  
[04:57] Technically it's a group of 2 to 5 cells that  produce the sperm. So let's compare it to semen,   which is the animal fluid that contains  sperm but is not exclusively sperm. Anyway.
[05:09] Like many of you, I am allergic  to certain kinds of flower semen,   and stupidly I moved to Knoxville, a warm,  humid city with abundant flowering plants,  
[05:23] situated in a valley that traps  air and keeps it from blowing away. Flower semen shoots up my nose where my immune  system mistakes it for a dangerous invader.  
[05:39] Pollen should be harmless at normal levels  of exposure, but for some reason my body   doesn't know that. So my body sends in its  Immunoglobulin E antibodies. IgE antibodies.
[06:00] A healthy person produces five basic kinds of  antibodies, and IgE is one we use to attack   tiny parasites that enter our bodies, including  the one that causes trichinosis — pork worm.
[06:17] My IgE antibodies bind with  otherwise harmless pollen grains,   which triggers the mast cells in my  connective tissues to release histamine,  
[06:30] which causes inflammation. Histamine kinda opens  up the capillaries, makes them more permeable to   white blood cells and proteins that flood  into my tissues to attack the invaders.
[06:46] The mucous membranes in my eyes,  my nose, my throat swells up,   they close off a little and they get itchy. My  eyes water and my nose runs as my body tries  
[07:01] to physically flush out the pollen that  it does not know is actually harmless. And I sneeze. As vomiting is to the digestive  system, sneezing is to the respiratory  
[07:17] system — an explosive ejection of whatever  outside substance I have recently taken in. Peanut allergy is another kind  of IgE-mediated allergy. It's  
[07:35] that same parasite-attacking antibody that's  involved. Among like 1 or 2% of Westerners,   their IgE antibodies bind to the particular  kind of storage proteins found in peanuts.
[07:56] Storage proteins are exactly what they sound  like. In animals, the equivalent would be the   casein in milk, or the albumin in egg white.  Gliadin in wheat, one of the gluten proteins,  
[08:11] that's a storage protein that seems to be  involved in people with gluten sensitivity. The storage proteins in peanuts are  called Arachin and Conarachin. When  
[08:24] people with the allergy eat these proteins,  or one of the other allergens in peanuts,   or when they breath in peanuts in the  form of dust, or get it in their eyes,  
[08:36] the IgE antibodies bind to those proteins,  which leads to the release of histamine   which causes inflammation that can be  dangerous or deadly. Like acutely deadly.
[08:54] Peanut allergy may not be THE most dangerous  food allergy. It depends how you define most   dangerous. It's certainly not the most  common food allergy. Among adults,  
[09:08] the most common food allergy is shellfish, among  kids it's either eggs or milk. But peanut allergy   is a particularly bad combination of severe  and common, which is why you've heard so much  
[09:27] about it. Also, kids tend to NOT outgrow  it. Most kids will outgrow their egg and   milk allergies. Most will not outgrow their  peanut allergies. About 80% do not outgrow it.
[09:45] Now, part of the peanut's bad  reputation as an allergen is,   no doubt, the result of media hype. But  it is absolutely NOT ALL media hype.  
[09:59] The reactions some people get really  are awful and sometimes deadly. Why? Several factors, including but not limited to...
[10:12] 1) Potency. Peanuts just have a lot  of allergens in a very compact form. 2) The effect of cooking. If you're interested  enough in cooking to be listening to me, I don't  
[10:31] need to tell you that heat changes proteins.  Some proteins become less dangerous to allergic   people when heated. The ones in peanuts become  more dangerous, specifically when dry roasted,  
[10:49] which is an extremely popular way to  prepare peanuts in the Western world. Globally, wet preparations are more  popular, and that may be one reason   that peanut allergies are rare beyond the  West. Roasting peanut proteins has been  
[11:07] shown to create more binding sites  for IgE antibodies. That's unusual. 3) How they're digested. One of our  biggest defenses against dangerous  
[11:24] food of all kinds is our digestive system.  The acid. The enzymes. These break down our   food into chunks that we can absorb through  our intestinal lining but they can also kill  
[11:36] some pathogenic microorganisms,  they denature some toxins, etc. Peanuts, along with some tree nut allergens,  can resist being broken down. And peanut  
[11:51] allergens have been shown to actually inhibit the  action of some digestive enzymes. What's more,   they have this unusual ability to cross the  gut lining and enter the bloodstream intact.  
[12:06] They literally change the bonds between  gut cells to squeeze themselves through. Thanks to the Australian molecular biologist  Dwan Price for posting a very readable list of  
[12:21] those factors with scholarly citations. Linked  in the description, along with other sources. So what does all this get us? A powerful allergic  reaction that is systemic rather than localized,  
[12:38] the way my little nasal allergies are. The  peanut allergens go all through your body. With a relatively minor reaction  you may feel itchy, get a rash.  
[12:52] Then there's gastrointestinal effects — cramps,  diarrhea. Respiratory effects — sneezing fit,   asthma attack. And the circulatory effects.  Histamine causes your blood vessels to open up,  
[13:10] to supply extra white blood cells to fight the  infection, which in the case of an allergy is   imaginary. When all your blood vessels open up  wide, when they dilate, your blood pressure drops,  
[13:25] because you have the same amount of fluid  passing though suddenly wider pipes. A really, really severe allergic reaction is  known as anaphylaxis. The Greek root phylaxsis  
[13:42] means protection. Ana means ... a bunch of  things depending on the context. In this   context it means "against" or "without." Without  protection. Or the inverse of protection. The  
[13:58] immune system is meant to protect you,  but anaphylaxis is when it goes nuts,   as it were, and does the opposite of  protecting you. As opposed to prophylaxis,   which means for protection. A prophylactic  drug is one that helps prevent a disease.
[14:16] For a mild allergic reaction  you can take an antihistamine,   like benadryl. For full-blown anaphylaxis,  basically the only treatment is epinephrine,  
[14:33] which is literally just another name for  adrenaline. You inject the hormone adrenaline   directly into your muscles, which has the effect  of rapidly constricting your blood vessels.  
[14:47] That's why people with severe allergies  carry epi-pens, for an emergency injection. Without the epi-pen, a person with anaphylaxis can   die from asphyxiation — the throat or the  tongue swell up so much they can't breath.
[15:06] They can die from their drop in  blood pressure — not enough blood,   not enough oxygen reaching the heart, heart  attack. This is called anaphylactic shock. The allergic reaction to peanuts  usually happens really quickly,  
[15:22] within minutes. Sometimes it's delayed a  couple hours, or there's a second phase of   the reaction a couple hours later, when  other biological pathways get involved.
[15:35] As always with this kind of content, I  am massively oversimplifying the science,   to the extent that I can  even comprehend the science.
[15:47] We don't know exactly how prevalent peanut  allergies are. Some studies come up with   1% of people in Western countries, some  come up with 2 or 3, or 4% among kids  
[16:00] specifically. Most studies have historically  shown the rate rising, rapidly, in the West. Then came a study in 2008. Lots of medical  research looks specifically at Ashkanazhi Jews,  
[16:23] for a number of reasons. Genetically, they're  relatively homogenous, and that can help you   learn certain things. And then there is the  existence of the modern state of Israel.
[16:35] Because Israel exists, you have large populations  of Ashkanazhi Jews living in the U.S. and Europe,   and then you have a large population living  in the Middle East, and these populations,  
[16:53] mostly, did not diverge until relatively  recent geopolitical events. So you have   lots of people with very similar genes  living in two very different places,  
[17:09] two very different environments,  different cultures, different food. In 2008, the British pediatric allergist  George Du Toi found that Jewish kids in  
[17:23] the UK were 10-times more likely to develop peanut  allergy compared to their counterparts in Israel.   The biggest difference, he determined,  is that Israeli kids eat this snack  
[17:40] brand called Bamba as their first solid  food. It's puffed corn, like a Cheeto,   but instead of being flavored with cheese  powder it's flavored with peanut powder.
[17:54] And like everybody eats Bamba  in Israel, so its always around,   and parents found it to be a good first  solid food for babies because they can   grab it easily and it kinda melts in your mouth  even if you don't have teeth to chew it yet.
[18:13] George Du Toi hypothesized that very  early peanut exposure might train kids'   immune systems to not freak out. Little  kids with eczema and egg allergies are  
[18:30] way more likely than most to develop  peanut allergy, so he looked at kids   with eczema and egg allergies. Some  got peanuts, some didn't. Overall,  
[18:43] early exposure to peanuts was shown to prevent  the allergy in like 80% of kids, with the effect   lasting as long as the observation continued,  into adolescence. That was published in 2015.
[19:02] So, public health officials all over  the Western world got the word out   to pediatricians and parents. They used  to tell the parents of high-risk kids to  
[19:16] avoid eating peanuts — kids  with eczema or egg allergy. Now they were saying, Sorry, we were wrong,  definitely give high-risk kids peanuts,  
[19:28] early and often, starting around 6 months  old, obviously under the observation of their   doctor. Give them peanut butter, peanut snacks,  whole peanuts when they're old enough to chew.
[19:42] More recently, in 2021, the advice  was updated to cover all kids,   with or without particular risk  factors. Peanuts. Early and often.
[19:58] Did this new advice have any effect? Yeah,  according to this new study out of Children's   Hospital of Philadelphia. The older study we  were just talking about was a clinical trial,  
[20:16] which is kinda the gold standard for health  research. This new one is an observational   study where they're just analyzing the electronic  health records of free-living humans. That allows  
[20:30] you to study WAY more people in more realistic  circumstances, but the evidence probably isn't   as good. You can learn what is happening, but  it's hard to nail down WHY it's happening. So,  
[20:47] take this with the appropriate grain of salt.  We'll learn more as other studies come out. What they were able to show in this new  study is that among little kids in the U.S.,  
[21:03] since the introduction of these new public  health guidelines encouraging people to feed   babies and toddlers peanuts, the rate of kids  developing new peanut allergies has dropped  
[21:18] almost in half. And you know what dropped by a  third? IgE-mediated food allergies generally,   not just peanut allergy, which is not all  the food allergies but it's a lot of them.
[21:37] In this last decade, peanut allergies have  ceased to be the most common food allergies   among Western kids. It's now egg allergies,  which they are far more likely to outgrow.
[21:52] Were the new guidelines the cause of this drop?  Can't say for sure, but there's no other obvious   explanation. We'll know more as more work is done,  in more places. Peanut allergy is rare outside  
[22:16] the West, but it is rising in Africa, in Asia,  seemingly hand-in-hand with economic development.  
[22:29] Japan has some peanut allergies, and  Japan is rich. Has been for a while. Peanut allergy may be yet another disease  of affluence, which we here on the Ragusea  
[22:44] channel classify as "good problems to have."  They still suck, they're still problems,   but it's better to have these problems than it is  to lack the money that leads to these problems.
[23:00] Why don't the poor kids of the world get  peanut allergy as much as the rich kids?   Nobody knows. I've read through a  bunch of literature examining this  
[23:13] phenomenon. Whatever the cause, it's probably  multi-factorial. It's not just one thing. Kids in poor countries may be less likely to  be diagnosed because they get worse healthcare,  
[23:27] that's probably a factor. There might be  a little survivorship bias — poor kids   with food allergies are more likely to die  before they even get a chance to be studied.
[23:41] That's an extremely sad way  to put it. Appropriately sad. There's the thing about dry-heat peanut  preparations being more popular in the West,   whereas peanuts are often boiled in Africa, for  example. Dry heat makes the allergen more potent.
[24:00] There's gotta be big environmental factors at  play. One study found that ethnic-Asian kids born   in the West are 5-times more likely to develop a  nut allergy than their counterparts back in Asia,  
[24:15] whereas White kids born in Asia had a much lower  risk than their counterparts back in the West. And when I say the West, I'm talking about Europe,  the U.S., Canada, Australia — geographically  
[24:33] far-flunch places, so it's probably not so  much about the place, but rather the lifestyle. Actually, I take that back. There is  some research looking at the place,  
[24:46] in particular the distance from the  equator. How much sunshine you get   and therefore how much vitamin D  you synthesize could be a factor.
[24:58] Per capita epipen prescriptions  are 4-times more prevalent in the   Northern U.S. than in the Southern  U.S. Could it be the sunshine? Kids born in the winter when the days are  shorter have more T-cells in their cord  
[25:16] blood compared to kids born in the summer  when it's sunny — that could be relevant.   And the reason you still see differences  between ethnic groups even in the same place,   the same latitude, same sunshine, could be  the result of genetic differences arising  
[25:33] from their ancestors having  gotten more or less sunshine. But the lifestyle has also gotta be relevant.  It IS relevant. We know that diet plays a role.  
[25:46] We've been talking about that this whole  time. Parents in rich countries have the   privilege to fuss over their baby's diets  a little more, to feed only breastmilk  
[26:00] or formula for longer before introducing  other foods. It's possible that may be a   net benefit for health but higher risk of food  allergy comes along with it. We don't know.
[26:17] You must always be wary of explanations  that seem particularly attractive to you,   because you'll generally find a way to  substantiate them, whether they're true or not.
[26:33] So I probably shouldn't say this, I probably  shouldn't even think this, but I am attracted to   the hygiene hypothesis, which is basically that a  richer life is a cleaner life, it's a more indoor  
[26:50] life, it's a life where you have the privilege  of being a picky eater without starving to death,   and you just get exposed to less stuff in  your developmental years, which could lead  
[27:04] to allergies, could lead to type-1 diabetes and  all kinds of other immune-system related diseases. I suppose all diseases are immune-system  related, but you know what I mean.
[27:20] The hygiene hypothesis is also something  that researchers in this area talk about,   it's not just me bringing it up, though I  do find it to be a really compelling idea.
[27:32] But let's finish by reminding ourselves once more  about good problems to have — they are problems,   but they're generally better than the alternative.  
[27:46] Still, I think I need to kick my kids  outside more often. And get them to eat   more kinds of stuff. Thank god they've  always eaten peanut butter, at least.
[28:02] Make good choices. Talk to you next time.