Pass the nuts. Please.

When I was a young-un no one ever heard about food allergies. Of course there were food allergies. We just never heard much about them. But now we not only hear about them, we hear about people, often children, who die from food allergy. Often peanut allergy. What's really weird about this is that in my day kids lived on peanut butter. Now some of them die with the slightest whiff of peanut antigen. And there seems to be peanut antigen in a lot of things, either by design or by cross contamination of equipment. Peanut antigen, you might think, is one of the most potent food allergy proteins around. It turns out there are even more potent nut allergens. Cashews:

The allergic reaction to cashew nuts is more severe than peanuts, says a new study that deepens our understanding of food allergies and highlights the need for clear labelling.

"Cashew nuts present a considerable hazard, being hidden in a wide variety of commonly ingested foods, such as Asian meals, sweets, ice cream, cakes, chocolates and they are increasingly used in commercially prepared pesto sauce instead of pine nuts," wrote lead author Andrew Clark in the journal Allergy.


The researchers, from Addenbrookes Hospital (Cambridge University Hospitals) and Queen Elizabeth Hospital, Kings Lynn, matched children whose worst ever reaction was to cashew nut (cashew group, 47 children) with children whose worst ever reaction was to peanut (peanut group, 94 children). The comparison matched the children according to sex, age of reaction and presentation, amount ingested, and asthma.


The researchers note that wheezing and cardiovascular symptoms were reported more often during reactions in the cashew than compared to the peanut group, while those allergic to cashews also received intramuscular adrenaline more frequently.

"A recent study showed that 10/37 (27 per cent) of nut-allergic children were unable to correctly identify the type of nut to which they were allergic," wrote the researchers. (Food Navigator-USA News)

The point of this medial article (A. T. Clark, K. Anagnostou, P. W. EwanAllergy, "Cashew nut causes more severe reactions than peanut: case-matched comparison in 141 children," 62(8):913-916, 2007) is that peanuts shouldn't get all the glory. When you think nut allergy, you might think not just of peanuts but also cashews.

And hazelnuts. And Brazil nuts. Ahh, the good old days. No thinking required.

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A modest academic point. Potency is a dose concept: how much stuff (mg/kg, for example) is associated with a particular effect (50% of population with wheezing). Potency should not include the severity of the effect or effects. More potency means lower dose to produce an effect, not necessarily a more severe effect. Potency is an elusive idea with an allergic (immune mediated) response vs. a direct toxic response of the organism.

While we are at it, peanuts aren't nuts, and I'm not sure whether cashews are either, or whether there is any mechanistic aspect of "nutness."

By Frank Mirer (not verified) on 21 Jul 2007 #permalink

Peanuts aren't a nut allergy because peanuts aren't peanuts; they're legumes. Not knowing anything about the physiology et al of the allergy, I'd hypothesize that the allergens in peanuts are different than those of nuts.

Frank, RPM: Peanuts aren't "nuts." This is partially true. I teach my students that, because, well, I'm a professor. But peanuts, as a food category to most people, are indeed nuts and if you ask someone if they have an allergy to "nuts" and they do to peanuts, they will say, "yes." Foods, whether classified as nuts or not, have many potential allergens and people allergic to peanuts are often allergic to other foods that are also called nuts (and are). Anyway, whether a "food" is a nut is not exactly the same thing as whether a specific botanical species or genus is classified as a nut. That's my pedantic response.

Regarding Frank's point about "potency", he is perfectly correct about this. So the fact that both have allergens and one may cause more severe a response doesn't speak to potency. I would actually go farther and say that for allergic responses the value of potency is probably less than for other adverse responses as the original signal (the biological dose) is being amplified by an immune system whose gain settings are very different for people with different histories.

If anyone wants to get nitpicky about it, neither the peanut or the cashew are technically nuts. The peanut is a legume, as mentioned above, but it is also a seed. The cashew is also a seed. True nuts are the whole fruit of the plant, containing the seed.

Sb-ers' seem united on one thing: Creationists are nuts. But sometimes a tomato is just a tomato, even though sometimes the cigar you insert in your tomato is more than a cigar and the tomato is more than a tomato.

And then you have my DD who is allergic to peanuts but loves cashews (and almonds, but not brazil nuts...).

Or my other half, who has anaphylactic reactions after eating peanuts, soy, wheat, celery, rice, lupins and probably a few other things, but only if he exercises after he eats them (exercise induced anaphylaxis). After the first six, we gave up trying to identify triggers and now just carry an epipen everywhere, and don't go out dancing after dinner.

By attack rate (not verified) on 21 Jul 2007 #permalink

AR: Wow. Shows what I know. I hadn't heard of EIA so I googled it. Not recognized until 1980 and of unknown prevalence but expected to become more common or more commonly recognized. Interesting (unless you suffer from it).

But peanuts, as a food category to most people, are indeed nuts and if you ask someone if they have an allergy to "nuts" and they do to peanuts, they will say, "yes."

Yeah, I find I have to qualify my allergy to nuts as being to "Tree nuts", since I have no trouble with peanuts, which confuses the heck out of most people.

Fortunately, it's a pretty mild allergy, so I don't have to worry about "traces of nuts"

So with EIA you can't go dancing after dinner. . . I am going to goggle that too.


I'm glad I don't have that problem, nuts, tree nuts, assorted legumes, whatever. I have a pretty severe dairy allergy that only seems to be getting worse with time (yes, allergy; lovely histamine-reaction symptoms and Uncle Tom Cobbley and all), and I don't want to be the second person in Ontario (that I know of) to die of a dairy allergy...

So what's going on here, Revere? Is this some kind of systemic-environmental synergy effect, or is it a case of better diagnosis, or has the cultural shift from ignorance of food allergies (and/or outright denial) to awareness allowed some of these people to actually live beyond infancy? (Me, I wouldn't be surprised if severe food allergies actually accounted for a lot of the "crib deaths" of yesteryear.)

By Interrobang (not verified) on 21 Jul 2007 #permalink

Hot damn. This has nothing to do with your post today Revere but did anyone else notice the Dow 'human element' add with the black guys back, at the top of the page?

I guess they expect sex to sell chemicals, yowza he's hot!

By Lisa the GP (not verified) on 21 Jul 2007 #permalink

Interro: There are a variety of theories but I don't know anyone who really knows what's happening or if something new is happening at all. Very, very curious, though.

Thanks very much. I am kind of wondering, in part because I'm working on a long-term research project on systemic illness. My "crib death" hunch stems from knowing someone who is one-third of a set of triplets, born in 1943. She says her parents told her that her two sisters were weak, so the doctor gave them a "stimulant shot" containing alcohol, whereupon they stopped breathing and died. At the time, they dismissed the phenomenon as being what happens with weak, sickly multiples. However, my friend has an anaphalactic reaction to alcohol, diagnosed in adulthood.

(On topic to much of the rest of the blog, that same friend went from being one of five children to being an only child, as her two older brothers died in the influenza epidemic that hit southern Ontario in the summer of 1950. She had a strange upbringing, for perfectly understandable reasons...)

By Interrobang (not verified) on 21 Jul 2007 #permalink

Damm...I've been eating peanuts for years thinking that they were nuts and therefore good for me.That's it! I've finished with the "expert food health Nazis".Moreover,I observe that many, if not most of the food "worriers" who abound today, are simply neurotic.
Yes I can spell anaphylactic reaction and have seen the consequences that sometimes occur.I still maintain that the West has become so risk averse that we are in danger of disappearing up our own backsides.If the health Nazis proclaimed that allergies were fictional,I guarantee that the rate of public anxiety and morbidity would halve within the week.

The point about "nuts" is whether there is a chemical composition which follows from the biological function. However, if both cashews and peanuts are seeds, the distinction goes away.

By Frank Mirer (not verified) on 22 Jul 2007 #permalink

Frank: I wouldn't get too hung up on the botanical defintion of a "nut." It is a definition designed for their purposes, not epidemiology, immunology or public health. There is another "definition" of a nut that must people use but it includes a variety of botanical categories (involving seeds, drupes and all sorts of other distinctions botanists are interested in but the rest of us aren't). Their categories were certainly not meant with allergy in mind.

Sometimes you feel like a nut, sometimes you die of anaphylactic shock.

By wenchacha (not verified) on 22 Jul 2007 #permalink

I've wondered about the apparently increasing number and severity of peanut allergies myself.

Given the relatively few types of peanuts in production farming at any given time, I've wondered if there is something in the varieties of peanuts that have proven more resistant to disease/fungi that might also be triggering agents for these allergies.

I'd be in trouble for lunch at school today - peanut butter and jelly was my lunch for 12 years.

Perhaps it was all the cigarettes, martinis and sun-drenched afternoons by the pool, slathered only in baby oil our mothers indulged in while we were in untero that enabled our bodies to be impervious to insignifant annoyances like peanuts.

When I was a kid, the only time I ate nuts(notnuts) was when I ate peanut butter and jelly sandwiches. Today I'm exposed when I eat cereal, pasta, etc.. Now I can't avoid HFCS. So, how long till children start dying from corn allergies?

It's weird that the food allergies that are on the top of the lists like peanuts, corn, and tomato are also new to non Native Americans, these foods were only found in the Americas. The rest of the world wasn't introduced to these foods until after 1500 or so.

By Rapid Heartbeat (not verified) on 22 Jul 2007 #permalink

So tell me the prevalence of food allergies in Native Americans.

By JohnnieCanuck, FCD (not verified) on 22 Jul 2007 #permalink

Tomatoes are fruity, some nuts are veggie.

(= fruity tomatoes, veggie spell it out)

Bees aren/t dying because of an allergy to flowers.

Have to dash - Indonesian on the stove - coconut milk, peanut sauce, crab omelette and more - the only allergic guest has an allergy to eggs but I/ve tested him out before with chocolat mousse (yellow plus whipped white) and it went down smiley smooth with no after effects. One person did notice, Why are you peering at Hugo?

Light! Sorry. Still. Points. Who knows. Life.

Huge literature. No time.

A very minor nitpick: "Youngin'" should be "young-un." It's short for "young one."

By Georgia Sam (not verified) on 23 Jul 2007 #permalink

Georgia: LOL. That's what happens when the young'un gets to be a geezer. I will fix.

Ana: Some things people call allergies for simplicity's sake are really food sensitivities, which can cause things like headache, fatigue, or GI problems, but not rash or difficulty breathing. The symptoms don't necessarily show up right away. Somebody not keeling over at the dinner table doesn't mean they don't have a real food sensitivity... or worse.

One member of my family has celiac disease. If she eats something containing gluten (from wheat, barley, possibly oats, the evidence is unclear), she'll feel yucky, but only three weeks later, after the cilia in her stomach have withered and she's no longer able to absorb nourishment properly. It was very low levels of B12, IIRC, that pointed them towards celiac after years of having no explanation for her symptoms.

I'm sure some people believe they have allergies or sensitivities that they don't, but experimenting with exposing people to their stated allergens on a hunch is irresponsible. You, after all, are not the one who will suffer the consequences if you are wrong, and they (and you) may never know you're the one who made them not feel well.

Oops... I said cilia in the stomach, I believe they're in the intestines. My mistake.

Yeah, I often wonder about why when I was a kid there were no food allegies. I mean, I didn't know of one single instance of this in the whole time I was in school. Now, you can't get within 100 yards of my kid's school with peanuts, dairy, etc. Is it possible that most of this is just BS? I don't want to seem insensitive but it just seems odd that this many allergies could crop up in such a short time span.

I'd guess it's the centralized processing of food --- whatever sensitizer exists (whether it's food, cleaning chemicals, something on the paint ....) is going to be passed out to just about everyone in the country, since so few plants process so much food nowadays. So if one janitor spills one chemical in one machine -- it's everywhere. In homeopathic amounts, perhaps, but sensitizers are one thing that does seem to work that way.

By Hank Roberts (not verified) on 25 Jul 2007 #permalink

Stu IMO, there may partly be an increase in the detection of food sensitivities. I know one child whose physical health and behavior improved markedly when his parents stopped feeding him wheat, although he had never had a violent allergic reaction to it. This sensitivity turned out to be transient, it passed after a couple years when he was very young. I suppose you could argue placebo effect, but what does a three-year-old know about why his breakfast cereal has changed?

However, with nut allergies, it seems, it's not something ambiguous or arguable. I have a toddler relative with a newly discovered nut allergy, and while she hasn't yet had trouble breathing, a bite of pilaf with nuts in it brought her out in an immediate rash. She even got a contact rash when she got PB on her face, and it's possible further exposures could increase her reaction, as happens with allergens. And as Revere's article indicates, nut allergies can be extremely serious, and even kill.

So there may be more detection, and there may be some small percentage of alleged allergies that are BS, but many are dramatic enough that there is no question. I suspect there is something environmental at work look at the burgeoning number of people with multiple chemical sensitivity, some of whom also have severe, unambiguous reactions. Or perhaps there's contamination, as Stu says. (Although, peanut butter does inherently come with a mold, I believe, that doesn't trouble most adults at all.)