Althouse: "For the past decade, studies have shown that introducing allergenic foods in infancy, as the immune system is developing, can help the body recognize food proteins as harmless...."

October 20, 2025

"For the past decade, studies have shown that introducing allergenic foods in infancy, as the immune system is developing, can help the body recognize food proteins as harmless...."

From "Peanut Allergies Have Plummeted in Children, Study Shows/Doctors have long recommended that infants avoid peanuts. But in 2017, experts officially reversed that guidance, and food allergies decreased sharply" (NYT).

60 comments:

The Vault Dweller said...: I've frequently heard that allergies are a First world problem with the theory being that living in a hyper-sterile environment primes the immune system to respond to many otherwise benign things, as if they were a threat. Take your kids outside and let them play in some dirt.; 10/20/25, 10:52 AM
rhhardin said...: You introduce puppies to peanut butter to get pills down.; 10/20/25, 10:52 AM
Lem Vibe Bandit said...: Science is not settled?; 10/20/25, 10:52 AM
n.n said...: Traditional wisdom.; 10/20/25, 10:54 AM
The Vault Dweller said...: This feels like a metaphor for how the Left-wing safe spaces, and anti-hate-speech practices ironically wind up making people more fragile and less resilient.; 10/20/25, 10:54 AM
Aggie said...: Precisely. Instead of 'trust the science' and 'the science is settled', we should be making a mantra out of 'trust the scientific method, science is never settled'.; 10/20/25, 10:54 AM
Oh Yea said...: What doesn't kill you makes you stronger; 10/20/25, 10:55 AM
Mike (MJB Wolf) said...: Yes. I suddenly developed a peanut and soybean allergy at age 40 and the "cure" is to reintroduce the allergen in tiny doses, working up to a total acceptance by the body after a month or so. It was a strange episode. Came out of the blue. But in the end I have almost no day-to-day allergies to deal with, after a lifetime of a barely functioning nose and lots of sneezing. The human body has six ways from Sunday (as they say) of attacking itself, just like our own political system. Autoimmune issues can be truly frightening in their sudden life-threatening way.; 10/20/25, 10:57 AM
Howard said...: I'm just glad that I have my peanut butter addiction under control now.; 10/20/25, 10:59 AM
Mike (MJB Wolf) said...: Best advice our pediatrician ever gave my wife was "let them eat dirt." People can't develop defenses to biological threats without exposure to them.; 10/20/25, 10:59 AM
Wince said...: rhhardin said...
You introduce puppies to peanut butter to get pills down.

And, ahem, other things.; 10/20/25, 11:03 AM
Jim Gust said...: No baby foods for my grandkids, much to my surprise. They are trying everything before they are 2.; 10/20/25, 11:03 AM
Achilles said...: We are allergic to most of the crap in the Standard American Diet.

People underestimate the amount of effort plants put into not being eaten.; 10/20/25, 11:09 AM
Achilles said...: There were also other factors in causing peanut allergies to trigger.

I am pretty sure that most peanut allergies were caused by a particular mold that grew on peanuts and they found a way to treat that mold.; 10/20/25, 11:13 AM
Wa St Blogger said...: Our immune system is a well trained army. If it doesn't have an enemy to fight, it will find one. All that hand sanitizer was not in our best interest.; 10/20/25, 11:14 AM
bagoh20 said...: Last to know? The experts.; 10/20/25, 11:16 AM
Wince said...: Achilles said...
People underestimate the amount of effort plants put into not being eaten.; 10/20/25, 11:18 AM
Original Mike said...: Aggie said..."Precisely. Instead of 'trust the science' and 'the science is settled', we should be making a mantra out of 'trust the scientific method, science is never settled'."

Well, I would say 'never say never', but in general I am in 100% agreement.

The food issue I am most intimately familiar with is eggs. Having a family history of atherosclerotic disease and lipid issues of my own, I was well aware as a young adult of the expert consensus that I should avoid eggs, because of the high level of cholesterol in the yolk. However, professionally ensconced in a cardiology department I was well placed to examine the research on the question and know that it has been apparent for decades that the cholesterol levels in the foods we eat have a very weak influence on our personal lipid levels. The cholesterol in our blood comes from that our body manufactures itself from the fats we eat, not the cholesterol we eat. And what I found so disturbing about the expert consensus was its stubbornness, bordering on absolute refusal, to acknowledge new data as it came out. It took decades for the paradigm shift to occur. As a scientist, I find this proclivity to hold onto old ideas embarrassing. And I find the yard signs proclaiming 'We believe in Science', displayed by people who couldn't differentiate y = x, both amusing and disturbing.; 10/20/25, 11:23 AM
R C Belaire said...: My daughter's 4 kids played in the dirt and mud along with a flock of chickens, amongst 5 acres of woods in which all of them roamed. My son says those kids will probably live until age 100.; 10/20/25, 11:24 AM
Rocco said...: Achilles said...
“People underestimate the amount of effort plants put into not being eaten.”

I’ve seen The Happening and know what they’re capable of.; 10/20/25, 11:26 AM
Peachy+2 said...: the science is settled - they tell us all the time. And then it isn't.
'Trust the experts' - the left demand.; 10/20/25, 11:26 AM
Original Mike said...: Althouse, if you're reading, I just had a non-controversial comment I put a lot of effort into spam-foldered. If you see this, please release it.; 10/20/25, 11:28 AM
Aggie said...: SIde note, off topic: Is anybody else noticing weird behavior on the internet today, particularly to do with search functions in various platforms? It's as if the search has been narrowed to ignore a wide variety of the usual data to query, limiting the scope of the search such that nothing is 'found'? This includes, of all places, Amazon, where products bought in the past, on that platform, are not found when searched for. No response at all.; 10/20/25, 11:35 AM
Tom T. said...: We were not told to introduce peanut powder early for our first, and he is apparently allergic. We were told to do so for our second, and she is not allergic.; 10/20/25, 11:42 AM
Aggie said...: @Wince, Jonathan Harris, who played Dr. Jonathan Smith , the villain in that series Lost in Space, was also Chuck Norris' vocal coach.; 10/20/25, 11:44 AM
n.n said...: This comment has been removed by the author.; 10/20/25, 11:46 AM
Sean said...: Things we know that aren't quite so.; 10/20/25, 11:47 AM
Achilles said...: I haven’t been on the internet much today but I will say you cannot be paranoid enough going forward.

Filters are going to become much more prevalent and pervasive in policing content with the improvement in llms.; 10/20/25, 11:47 AM
n.n said...: The goal of plantifa is to either migrate and infest, or toxic progression through planned personhood without a viable posterity aborted as fertilizer. All's fair in lettuce and avocados.; 10/20/25, 11:48 AM
John henry said...: I've always wondered about the nut and esp peanut allergy. I think I went 40 years or more before I heard of it for the first time. It seems pretty serious and I am not belittling it but why was it not a thing before?

And now it may not be a thing anymore?

Seems odd.

I am not allergic to peanut butter but I am seriously at risk for gout attacks. Even small amounts like a Reese's Cup or a CFA sandwhich (fried in peanut oil) could trigger a horrible attack.

4-5 years ago the VA got me on Allopurinol and now I can eat peanut butter out of the jar with a spoon.

Howard, you didn't lose your addiction, you simply passed it to me!

John Henry; 10/20/25, 11:52 AM
Enigma said...: Allergies pertain to an immune system response, and it's great that early exposure limits these reactions. STILL, be aware that some foods involve dietary sensitivities other than allergies.

Peanuts are particularly TERRIBLE because they contain lectins, and lectins that cannot be destroyed through cooking. If you are sensitive, lectins tear your digestive tract open and cause heartburn, leaky gut, inflammation, etc.

Peanuts are a dietary evil because cooking doesn't destroy their lectins. Also see sunflower seeds, beans, potatoes, tomatoes, peppers, and more. Most get destroyed with cooking, but not peanut lectins.

So, even without allergies...be careful...

Next, consider the literal toxins in cashews, mangoes, and poison oak/ivy...; 10/20/25, 11:58 AM
Howard said...: I'm down to a 1-pound jar per week 😜; 10/20/25, 12:02 PM
Howard said...: I saw a recent paper that there is a amino acid contained in fatty fish and grass-fed beef that is linked to increase incidence of Alzheimer's disease and dementia. This is another example of scaremongering headlines that result from the reductionist theory of nutrition:

Reductionist Theory of Nutrition
The reductionist theory of nutrition is a scientific approach that focuses on breaking down complex nutritional factors into their individual components to understand their effects on health. It assumes that the health effects of food can be explained by the sum of its individual nutrients, such as vitamins, minerals, antioxidants, and macronutrients (carbohydrates, protein, and fat).
Key Principles:
Isolation of nutrients: The theory isolates individual nutrients from their food matrix and studies their effects in isolation.
Linear relationships: It assumes that there are linear relationships between nutrient intake and health outcomes. For example, consuming more vitamin C reduces the risk of scurvy.
Neglect of interactions: It often ignores the interactions between nutrients, as well as the influence of other factors such as food processing, cooking methods, and overall dietary patterns.
Criticisms:
Oversimplification: The theory can oversimplify the complex interactions that occur in the body when consuming food.
Lack of holistic perspective: It fails to consider the whole food matrix and the synergistic effects of multiple nutrients and bioactive compounds.
Ignoring cultural and social factors: It does not take into account the influence of cultural and social factors on diet and health.; 10/20/25, 12:08 PM
tommyesq said...: Aggie, there was a major internet outage that affected Amazon Web Services and is believed to have shut down access to about 50% of the web. Has been/is being resolved.; 10/20/25, 12:14 PM
wild chicken said...: When I was 3 my parent abused me by making me swim in the Los Angeles River. Which was mostly sewage at the time.

I look back and wonder how she could ever do that but come to think of it I have been remarkably healthy considering the way I treated myself later.; 10/20/25, 12:20 PM
Jamie said...: Re: Howard @12:08, what you're quoting is exactly the issue the now-infamous acetaminophen's (not circumcision, for God's sake) meta study was saying about most of the studies it analyzed: they were reductionist, and often - because they weren't "about" acetaminophen but rather were "about" the MMR vaccine or whatever, they considered administration of acetaminophen to be a confounding factor rather than a possible contributor to an effect.

As to this turnabout on medical advice: I wonder if anyone is keeping count of how many times in our lifetime Scientists™ have done a 180. It's been a lot.

I mean, I want to hear their recommendations. But I also want to hear their caveats, and I certainly hope the Public Health Scientists™ have developed a little humility after the fiasco that was COVID.; 10/20/25, 12:21 PM
Jamie said...: Though I doubt it.; 10/20/25, 12:21 PM
wild chicken said...: Actually I think my parent was just assuming it was like the 1930s when she and her siblings used to picnic at the Los Angeles River. Which was mostly sewage at the time.; 10/20/25, 12:21 PM
Eva Marie said...: Does this mean we’re days away from handing out bags of peanuts on airplanes again? I thank you and the descendants of Jimmy Carter thank you.; 10/20/25, 12:26 PM
Aggie said...: @tommyesq, ah-ha, thank you very much. That probably explains why my daily 'Worldle' hasn't come up yet, as well.; 10/20/25, 12:42 PM
Gemna said...: Don't give the experts credit here. They made the recommendation to delay allergenic foods without any evidence. This shows the importance of getting actual evidence before making recommendations.; 10/20/25, 12:54 PM
boatbuilder said...: There are allergens like poison ivy (urushiol) and epoxy resin for which the allergic effect is cumulative. You are immune until all of a sudden you aren't. People employed in the boat and similar trades working with fiberglass and resin have been completely disabled by this effect.; 10/20/25, 12:57 PM
D.D. Driver said...: "I've frequently heard that allergies are a First world problem with the theory being that living in a hyper-sterile environment primes the immune system to respond to many otherwise benign things, as if they were a threat. Take your kids outside and let them play in some dirt."

There is the story of this researcher who gave himself hookworms to test that hypothesis. His allergies went away.; 10/20/25, 12:58 PM
Fred Drinkwater said...: "Science is the belief in the fallibility of experts."
- some goof named Richard Feynman; 10/20/25, 1:12 PM
Jaq said...: George Carlin for the win.; 10/20/25, 1:19 PM
Jamie said...: I'll give researchers (at least) this much grace: it is VERY hard to study development, and studying child development is also fraught with ethical concerns that dwarf those in any study of adults. Plus there's the deep desire to Do Something when there's something that negatively affects children.

And, I guess, now we also have falling birthrates that make the few children we do have that much more precious, and falling infant/child mortality that make us expect every child to live to old age.

So... I guess it's not surprising that sometimes medical researchers advise in advance of data.; 10/20/25, 1:28 PM
n.n said...: Diet is processed through acclimation. Liberal consumption is fraught with risk of progressive conditions.; 10/20/25, 1:55 PM
Enigma said...: @boatbuilder on the sudden development of epoxy allergies:

Also consider that a notable percentage of medical professionals become allergic to latex over time per their "rubber gloves." A latex allergy can also involve foods high in latex such as a bananas, avocados, chestnuts, etc.; 10/20/25, 2:00 PM
JAORE said...: Our son was allergic to everything. Fortunately be did not have strong reactions. The SOP treatment was injections that slowly introduced the allergens. Soon enough he was "cured". If the docs can figure THAT out, why couldn't the nutritionists have done the same?; 10/20/25, 2:01 PM
Immanuel Rant said...: Re: Trust the Science

From Johnny Carson in the 80s - NEWS OF THE FUTURE
"Today's top story - OAT BRAN, THE SILENT KILLER. But first . . . "; 10/20/25, 2:51 PM
MadisonMan said...: Experts. Top. Men.; 10/20/25, 2:59 PM
MadisonMan said...: Also, @Fred, my preferred quote from him is "there is a considerable amount of intellectual tyranny in the name of science."; 10/20/25, 3:02 PM
Tina Trent said...: Ah, those intemperate scientists.

It's like watching Jane Austin characters choose their men.; 10/20/25, 4:15 PM
Tina Trent said...: Boatbuilder: it's not an allergy: it's the start of a disease process. I know a dozen furniture restorers, plexi cutters (like me), boat repairers, and finishers requiring solvents who died of brain cancer.

Take care of yourself. Wear your damn cannister mask. I know it sucks. It sucks less than brain cancer.; 10/20/25, 4:21 PM
Greg The Class Traitor said...: Doctors have long recommended that infants avoid peanuts.
Only the complete morons

But in 2017, experts officially reversed that guidance, and food allergies decreased sharply" (NYT).

Yeah, no shit, Sherlock. Your immune system has to be trained as to what's "normal" and what's "foreign". The idea "keep babies from being exposed to X, so they will only encounter it when their bodies have already defined what's 'normal'" was always world class stupid; 10/20/25, 4:25 PM
Tina Trent said...: One left an unborn son and a two-year old. No other medical problems. Died at 25. Worked in his dad's shop for a decade.; 10/20/25, 4:27 PM
Hassayamper said...: This phenomenon was noticed a lot longer than a decade ago, but ignored by all the good and the great of the medical and nutritional establishment.

Doubtless some of them were the same "experts" who recommended nine servings of carbohydrates daily, and thought that blood cholesterol varied in direct proportion to dietary cholesterol.; 10/20/25, 5:10 PM
Hassayamper said...: studying child development is also fraught with ethical concerns that dwarf those in any study of adults

Unless a little boy's mentally-ill mother becomes convinced he is actually a girl. Then medical ethics can get fucked, and the poor little chap will be subjected to life-altering tortures and mutilations that would make Dr. Mengele wince.; 10/20/25, 5:13 PM
Josephbleau said...: “ What doesn't kill you makes you stronger”

And by the contrapositive, what makes you weaker, kills you.; 10/20/25, 6:23 PM
Mason G said...: "Plus there's the deep desire to Do Something when there's something that negatively affects children."

Assuming they've managed to not be aborted. Prior to that decision, "Do something" could go either way.; 10/20/25, 6:56 PM