Peanut allergies have plummeted in children

The kids I see that have peanut allergies lived in bubbles. It seems like it is self-inflicted but I have no scientific evidence.

There are a ton of studies that indicate that early exposure to peanuts reduces incidence of peanut allergies. I'm not sure about other allergens.

https://publications.aap.org/pediatrics/search-results?page=...

And yet peanut allergy is rare in Europe. Pretty strange.

> I don't think there are any physics reasons why it'd be impossible

There is extensive evidence that the incidence of severe peanut allergies is significantly increased by the practice of avoiding early exposure in the absence of particular risk indicators, which is why that practice is now advised against.(IIRC, some of the first targeted studies were motivated by observed differences in incidence between the US where early avoidance had become common and Israel where peanut-based puff snacks were a common thing to give to babies not long after starting solid food.)

My brother was/is allergic to peanuts, and it was first noticed in ... 1978 I think, when he was 2. Horrible reaction, nearly died. I'm older, don't have it. A brother younger than both of us also has no allergy to peanuts. We were all raised in the same house, same foods, no bubble environment (the 70s were pretty unbubbled for most kids).

He also had a grape allergy, and reaction was quite severe, but he seemed to outgrow that by his 40s.

My first is allergic to peanuts and I don't think she lived in a bubble but she was born in late 2020 so probably a relative bubble compared to normal times. She was 8mo when she first had a lick of peanut butter, no other allergies and we quickly followed up with tree nut butter to head off anything else.

That reminds me of my parents who most often use peanut oil for cooking. I was eating food cooked in peanut oil every day. I was astounded when I heard in elementary school that people could be allergic to peanuts.

Right, allergies are likely a real thing, but I think there's many things nowadays where as soon as we hear of chances of something we go on this hyper vigilant avoidant mode, and that often makes the chances even greater, counterintuitively.

At some points, some things are bad luck, at least until we truly understand the mechanisms and causations.

I thought peanut allergies were roughly as common in Europe as the US, and a quick web search seems to back this up: https://pmc.ncbi.nlm.nih.gov/articles/PMC6021584/

My oldest is allergic and spent plenty of time in the sand and dirt. They were exposed to nuts pretty regularly, and fed small amounts from basically as soon as they were taking solid foods.

The hygiene hypothesis is widely accepted, including by allergists, and there's definitely data supporting it, but we don't understand the mechanism, so it's hard to say that it's about any one specific thing vs. many contributing causes that correlate with hygiene and other aspects of the environment around the kid.

The advice about early exposure clearly works though, and there's data to support that early exposure even after confirming the allergy can increase the chances of outgrowing the allergy.

My kid showed an allergic reaction the third time he had peanuts, at 6-7 months old. We hadn't lived in much of a bubble up to that point.

You say they live in bubbles, but is that before or after discovering the allergy? After the allergy is discovered, some amount of bubble-ing is necessary due to how difficult it is to be certain than something is peanut-free.

I think peanuts are eaten less commonly in Europe? Maybe it just doesn’t come up as much?

There is no allergenic proteins left in peanut oil or it would burn and be rancid at room temperature. Your anecdata is not relevant here.

Should clarify that the "hygiene hypothesis" has data supporting it for bacteria and allergens but not viruses.

I haven't searched through the literature, but these days pediatrician advice is to try to do early and regular exposure to all of the common food allergens as soon as they are ready to start solid foods (~6 month mark), if not even a little earlier in their milk/formula.

Europe is as much a location as the US. Eating habits in Finland are very different than in Spain. So any generalisation here will have people disagreeing. That said, I are lots of peanut butter sandwiches for lunch. It was normal.

Now we do understand why allergies appear, or at least we have theories that are being tested with studies such as this one. It's all about chance, very literally.

As lymphocytes are formed, they randomly rearrange their T-cell receptor / immunoglobulin genes, creating a random antigen specificity for each cell. [1]

Then, they get selectively killed if they react to self-antigens. [2]

Those that survive, if they ever meet their specific antigen, will selectively multiply [3] and do random mutations again [4].

  [1] https://en.wikipedia.org/wiki/V(D)J_recombination
  [2] https://en.wikipedia.org/wiki/Clonal_deletion
  [3] https://en.wikipedia.org/wiki/Clonal_selection
  [4] https://en.wikipedia.org/wiki/Somatic_hypermutation

The current theory is that allergies appear if: (1) some random lymphocyte rearrangement created affinity for that allergen and (2) the allergen was not "known to be safe" by the selection mechanisms of the body and that lymphocyte was allowed to survive.

Fortunately for food allergies, oral immunotherapy seems to be very effective if you can catch the allergy early (before 2 years old). We did for our oldest and the results are miraculous. It's a ton of work though, and I had more than a few near crash-outs from trying to get an 18 month old who doesn't really like the taste of peanut to eat a teaspoon of peanut every single day. That said, I don't regret it.

Even though we keep an epipen around and we make sure they're not eating peanuts, we don't practice strict avoidance anymore, we don't have to worry about the "processed on shared equipment" warnings, and there's no problem if he touches/inhales/eats peanut, meaning we can eat peanuts around him.

There are proteins left in raw pressed peanut oil (used for lower heat cooking and as a finishing oil, somewhat similar to EVOO), but not in highly-refined peanut oil (typically used for high-heat cooking/deep frying.)

Both will eventually go rancid at room temperature , though highly refined oil has a longer shelf life (both sealed and, even moreso, after the seal is broken.)

Always a good reminder that absolutism is dangerous. The medical field especially seems subject to this. It took me an insane number of years and multiple doctors and nearly being disabled from it to discover my thyroid condition in large part because "statistically it's mostly women who have thyroid issues" and the monstrously large range of "normal levels of TSH"

> Then, they get selectively killed if they react to self-antigens. [2]

There's also the ones that react weakly to self antigens and are kept around to put a check on everything else.

https://en.wikipedia.org/wiki/Regulatory_T_cell

The thymus is just insane.

Well, Mother Nature doesn't have to make any sense, so that's an advantage to her. This does make our nature - to try to understand - extremely difficult but makes no difference to her either way.

Huh. I'm male, my Thyroid is shot, and they weren't even surprised. They ran tests, they saw TSH is high and there's barely enough Thyroxine produced, and they went OK, you need Thyroxine, here's infinite auto-renewals, take as directed, and please get re-tested once a year to see if the dose needs changing.

They are. But everybody does occasionally run into peanuts or peanut dust so peanut allergies are extremely unlikely to go undetected.

Why would that be strange? Allergies seem to have a lot to do with ethnic background, family history, and environment. For instance, shellfish allergies are more common in Asia.

With tobacco you've got to start young if you want kids to be able to handle a pack a day by the time they are teenagers ;)