From a very early age, maybe 10-12 years old, I can remember making several repeated observations about how I differed from people around me. One, and I have no idea how this conversation came up, was that I could smell the sulfurous compounds in my urine after eating asparagus while other people could not. While the asparagus urine odor has been observed for centuries it was an interesting observation for me as a pre-teen. Later in life, once the Internet became available I was able to look up more technical information about that and add it to my arsenal of useless party trivia facts. I can also taste and smell the difference between cilantro and parsley and I like the taste while others I know can’t tell the difference or dislike it because it tastes “soapy” to them. Two other pieces of insight I’ve picked up over the years and the two most relevant to this post are that, mainly during outdoors camping with my family it was observed, by me and others, that mosquitos focused their attentions noticeably less on me than on others in the group and that I was immune to poison oak.
A couple of years ago, during the COVID-19 emergency I decided to get my genome tested (I chose 23andme) and the results reminded me of some of those early observations and how they were related to my genome.
For the asparagus urine smell I got the technical results and this simplification:
My cilantro results:
And the relevant Mosquito bite results:
I still can and do get bitten but it is infrequent. Since I am not a fan of spraying or rubbing mosquito repellents made from pesticides (nasty long-chain, multi-syllabic substances like ethyl butylacetylaminopropionate or N,N-diethyl-meta-toluamide – A.K.A. DEET) on my skin I instead dress accordingly with long sleeves, long pants, hat or beanie and often wear a hoodie to help protect my neck and ears.
Many insect repellents (or ingredients in them) are also known to cause damage to certain gear and materials which is another reason I would prefer to not use them.
Many bug sprays, lotions or wipes also just stink both from the active ingredients and inert fillers as well as added substances that mask those smells and make the spray or lotion smell “good.” As a human with a dog I can only imagine what something that smells strong and “bad” to me smells like to her with that amazing canine sense of smell. She might actually like it since she’s a dork but I also have no need for her to lick those nasty chemicals off me…either because she likes them or because she is “cleaning me.”
Urushiol is the component of poison oak that causes an itchy, red rash and possibly blisters to appear. Just like my lessened desirability by mosquitos, my love of cilantro and being able to smell the after effects of enjoying asparagus I expect there is a genetic component to my immunity from what is normally an 80% reaction via allergic contact dermatitis (ACD) and specifically Urushiol-induced contact dermatitis in the general population. As far as I can find though I see nothing relevant to that hypothesis in my 23andme results but they do keep adding new or expanded results on a seemingly monthly basis and I expect and am looking forward to see if my historical observations end up having some basis in medical fact. I did recently get the chance to retest the mosquito and poison oak observations when we camped at Horse Linto Creek. I am happy to report that it still seems to be true that mosquitos don’t prefer me and I am still immune to poison oak.
Since those first, early observations of differences between myself and others it has been a running joke among friends and family that “Mosquitos don’t prefer Eric” and “Why did we all get poison oak and Eric didn’t”… which are both great… for me. By not needing to use bug spray I am spared from the greasiness on my skin, the stink in my nostrils and the damage to my gear. By not worrying about Poison Oak reactions I can have physical contact with my dog even after she has been cavorting continuously through thick Poison Oak bushes. Those are small but welcome advantages when out on our adventures. Two less things to worry about or deal with. Now with these DNA results I mostly know why.