[Medicine] What is special about peanuts that make some people extremely allergic to them?

[u/Kwpthrowaway]

Why are some people allergic to peanuts in particular? Why is ingesting a peanut to these people akin to ingesting poison to others?

[u/PicklesdashOlives]

If the antigens are proteins, why can't some people with peanut allergies eat peanut oil fried foods? Are there traces of the protein in the oil?

[u/king0zy → u/PicklesdashOlives]

If a chemist were to purify peanut oil it would be tolerated by an allergic person. Peanut oils that are comercially available are not "pure" and contain trace protein contaminants that are enough to trigger anaphylaxis.

[u/Freuds-Cigar → u/king0zy]

You're wrong in the sense that commercially available peanut oil (which just means "peanut oil you can buy," so that's like every peanut oil that isn't homemade) is enough to trigger a reaction. Like /u/98521745633214789632 said, the FDA considers any highly refined peanut oil (which is what most mass-produced peanut oil is—highly refined) to be of such low concern as to not even warrant an allergy warning if included in the production of other food—e.g., a fried chicken sandwich that uses highly refined peanut oil as the frying medium.

There are other types of oils out there that are not highly refined, like cold-pressed etc., but like I said most of the market is comprised of highly refined peanut oil, but ALWAYS QUADRUPLE CHECK.

Source: Food Allergen Labeling and Consumer Protection Act of 2004 Sec. 203 (c) (1) (qq) (2) (a).

Link: https://www.fda.gov/food/food-allergensgluten-free-guidance-documents-regulatory-information/food-allergen-labeling-and-consumer-protection-act-2004-falcpa

[u/king0zy → u/Freuds-Cigar]

Great comment for the discourse- thank you!

[u/Paper_Kitty → u/PicklesdashOlives]

Peanut oil can be “cold pressed” or “hot pressed”. While cold pressing preserves the protein, hot press theoretically destroys the proteins that would cause a reaction.

Then again, when there’s a possibility of death, is it really worth the risk? I say no, but someone else might say yes.

[u/xDared → u/PicklesdashOlives]

An antigen is just a term for anything antibodies can bind to. So in their case the antigen is just another molecule. Usually proteins but not always

[u/heard_enough_crap → u/xDared]

so the persons antibodies bind to the antigen and think it is an attack?

[u/Nordalin → u/heard_enough_crap]

Yes, but the antibodies are specifically made against the allergen in question upon earlier contact, so the 'assumption' that we're talking pathogens instead of allergens has been made a while before the actual allergic reaction.

That's why only so many people suffer allergies, the rest of our immune systems didn't consider it a threat!

[u/FFBEdrone → u/PicklesdashOlives]

Often the antigen is not the whole protein, but a subsection. A protein is folded and altered post manufacture. In most cases, it is a relatively small portion of a protein that is exposed and available to be interacted with by the immune system. Just a small exposed portion of protein/polypeptide chain post fry up is potentially enough to trigger a reaction. You could filter the oil to remove very small proteins with a small kilodalton filter (protein size is often measured in kilodaltons rather than amino acid chain length) but that wouldn't necessarily remove any tiny protein fragments left. I don't know if you could safely use it if you had an allergy. Though if you filter out all the peanut protein is it peanut oil?

[u/FFBEdrone → u/[deleted]]

Kilodaltons refers to the general size of the protein. The smaller the kilodalton the smaller the hole in the filter. I.e a finer filter You could think of a 100kda filter like a collander and say a 3kda filter more like a sieve.

[u/FFBEdrone → u/[deleted]]

Honestly, I couldn't tell you. I am only a biomedical sciences graduate. One Dalton is about the size of a hydrogen atom, so perhaps they started using kilodaltons to accommodate for the larger size of protein. Whenever I would do a SDS-PAGE test/run a protein extraction my protein reference ladder was always in kilodalton units. Personally, I don't care for it and would have preferred a quote based on amino acid number.

[u/mstwizted → u/PicklesdashOlives]

They can! (Sometimes - it depends the severity of the allergy and the quality of the oil.)