In case anyone landed here after listening to this week's Savage Lovecast, I wanted to point you in the right direction. Please be gentle - that was my first time being interviewed for anything like that, so I was a bit of a nervous wreck.
For the uninitiated - a couple of weeks ago on his podcast, Dan Savage fielded a question from a woman that thought a chunk of mushroom managed to make it through her boyfriend's digestive tract untouched and end up in his ejaculate. Dan rightly dismissed this notion, saying that things don't go "from guts to nuts." This is certainly true for solid pieces of undigested food, but as I wrote about earlier this year, allergens actually can go from guts to nuts.
If one partner ingests something that the other is allergic too, small molecules from the digested food will be absorbed into the bloodstream and make their way into secretions, including sweat and semen. This can then cause an allergic reaction in the other partner.
I also mentioned that women can develop allergies to semen itself, or more specifically, seminal plasma.
In this case, the immune response isn't directed at some foreign molecule that makes its way into semen, it's directed at a protein that's part of the semen itself.
If you're interested in what allergies are (other than a huge pain in the ass), I recently wrote a series of posts explaining what exactly is going on, to the extent that we know. If you have any other questions or you want to leave feedback, feel free to leave a comment or send me an e-mail.
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As the resident go-to guy on the science of allergies perhaps you could answer a couple of questions related to my allergies to grass and other pollens:
1) Why is it that I can take something like Loratadine and still have attacks?
2) Why is it that one of the oldest antihistamines Diphenhydramine, Bendryl, works when other antihistamines fail?
3) Humans have been around pollen and grass since there were humans. I would think that long term allergies to these materials would be effectively deselected through evolution. Nothing sexy about a person with swollen red eyes and nose who sneezes a lot and leaves a snail trail. When I am in the middle of an attack sex is pretty much the last thing on my mind.
Rumination) Diphenhydramine is really neat stuff We once, lacking any other options, saved a guy who was deathly allergic to bee stings by stuffing him full of Benedryl and strong coffee. Held him for the hours it took to carry him out.
I've long used it as a sleeping pill. A couple years back I stitched myself up in the deep woods and used the powder from a Benedryl capsule to dull the pain. The cut healed quite well and, other than those alien critters that burst out of my chest every so often, there were no side effects. Is there anything Diphenhydramine can't help out with?
@ Art - I'm not a medical doctor, so unfortunately I can't really comment on why specific medications work or don't. Histamine isn't the only problem in an allergic reaction, and Benadryl has other effects as well that may play a role (like the neurologic effects you mentioned).
As to the evolution of allergies, yes, we've been around pollen and grass forever, but we were also around parasitic helminths. It seems to be that these worms can play a role in regulating our immune systems, and for reasons that we still don't understand, removing them from our society has increased our susceptibility to allergies, autoimmunity and other hyperinflammatory disorders. In fact, in the regions of the world that parasitic worms are still endemic, there's almost no allergy, and almost no autoimmunity.
"It seems to be that these worms can play a role in regulating our immune systems, and for reasons that we still don't understand, removing them from our society has increased our susceptibility to allergies, autoimmunity and other hyperinflammatory disorders."
Perhaps I should 'take two tapeworms and call you in the morning'. LOL.
Has anyone studied the effects upon nasal allergies a few resident worm might have? I've read that a few worms have been suggested for inflammatory bowel disease.
Please don't. :-)
There are animal studies or ongoing human clinical trials for just about every autoimmune disorder from brain to bowel. I don't know if there are clinical trials looking at helminth therapy for treatment, but there are definitely promising animal studies. It's amazing that a worm (or parts of a worm) in your gut can affect the immune system in your brain, but that's what the data seem to be telling us.
Hey Kevin you didn't sound too nervous on the podcast but any way I am looking forward to reading the links your provided above :)
You didn't seem nervous. Looking forward to following the blog.
@ Hugo and Aaron - That's nice of you guys to say. I think the tech savy at risk youth managed to edit out a lot of "um" and "ah" and do some other magic. Or maybe I was just being hard on myself - listening to it wasn't nearly as bad as I expected.
Thanks for dropping by!
There are 3 things you need to know:
1) WNYC's Radiolab has a program titled "Parasites" that touches on the intestinal worm/immunology relationship - it may be more entertaining than academic but it's a good listen.
2)As a student working toward his doctorate in pharmacy I can tell you there are some things Benadryl can't do: help the Cowboys into the playoffs, and solve the payroll tax holiday standoff (sedation and CSPAN do not make good bedfellows). @Art, Diphenhydramine is rapibly metabolized by the liver giving it more potent albeit shorter lived activity than Loratadine, which takes multiple days to build up metabolite serum levels for efficacy. Diphenhydramine also competitively inhibits acetylcholine in the body, suppressing the parasympathetic nervous system, making it a very useful systemic agent. You're right about it dulling pain, too. When applied topically it blocks sodium channels of the nerves, prolonging the refractory period, and decreasing pain signal frequency. However, Benadryl unlike Loratadine crosses the blood-brain barrier and is not recommended for prolonged usage.
3) @Kevin, you didn't sound nervous at all on Savage Love, and in fact I may have developed a small voice crush on you. Also, I received my undergraduate in Chemistry and, not to embarrass you but, if any of my classmates were as cute as your picture is I wouldn't have gotten nearly as much work done.
Kevin, you're too modest! You did a great job on the lovecast: very articulate and charming (I think Dan thought so too!). Also, nice blog. I have yet to figure out how to channel my own PhD learnin' into a forum with an actual audience :)
Hi Kevin,
Re your response to Art: Just read a piece on CD and what regions of the world are affected by it. While European countries and places colonized by Europe have the most documented cases, other less developed countries do not seem to fall too short. The obvious connection to CD (besides genetic) is wheat consumption, but of course there are other autoimmunities affiliated with it.
One thing I have noticed is a concurrent move away from tradition foods with an increase in immune imbalance. Since GALT sits right beneath the gut, the connection seems plain to me. Perhaps oversimplifying?
Do you think that the modernization of wheat grain itself, the prolific use of wheat (and other grains with their own prolamins), and the modern foods that the world eats at large could play a role in the increasing wackiness of the immune system (autoimmunity, allergies, and the like)??
@ Katie - Thanks for the encouragement!
The trick is writing for a while with no audience. I don't even think my parents were reading me when I started. Put links on facebook, put links on twitter, and if people like what they read, they'll keep reading. It's disheartening to have like 5 pageviews on something you spent an hour or two writing, but that's the price you pay.
@ Megan - CD is tricky. It's not exactly an allergy, and it's not exactly autoimmunity, so it doesn't fit nicely into any of the models we have for describing those disorders. To be honest, I don't know a lot about it (maybe I'll do some research and write a post about it soon). GALT is a strange and wondrous secondary lymphoid structure, and most of what we know about it we infer based on the similarity with lymph nodes, but since they aren't rigidly defined structures, they're very difficult to study. It's clear that Tregs in the gut can have systemic effects (hence the effect of intestinal worms on brain autoimmunity), but how and why these things are happening I think is still unclear.
I think we need to be careful with some of these correlations. Moving away from traditional foods is also correlated with moving to cities and better hygiene, the later having a definitive link with the increase in hyperinflammatory disorders. And as far as I know, people living in places like japan where rice is still the staple grain have similar levels of autoimmunity/allergy but presumably no CD.
@ Jayme - Sorry, your comment got trapped by the spam filter and I only noticed it because mine just did to :-/
1) I love raidiolab, and I heard that podcast. It bugs me a little because what that guy was doing (I think) is quite irresponsible, and I don't think they balanced his miracle cure quite enough with the good science (and it's out there!). In general though, it's awesome.
2) Thanks for the info! Stick around - I'll be expecting you to field any drug-related questions that pop up in the future.
3) Awe shucks :-)
Great point. Thanks Kevin!
Would love to see a post on CD!
I'm just swinging by to whip up some margaritas. Don't mind me.
@ Justicar - What does that even mean? If I had tequila, I think I'd know.
I've said too much. Here, have a pretty miniature umbrella. This one's blue for no particular reason. <):o)~