I got crop dusted on my flight the other day and I thought I was gonna get diabetes from one person running to the bathroom. And then a couple weeks ago it smelled like death walking.
After that I realized that I’ve noticed most everyone that is fairly old (70+) is similar. So what causes that compared to the normal methane composition of adults?
The “Death” smell is normally associated with an inefficient digestion, which causes amino acids to break down - relevant ist especially cysteine, which contains Sulfur and therefore smells intensive. Can also happen if you overload on proteins without any pancreas issues.
The “sweeter” smell can have multiple reasons, but having an disturbed gut microbiome is the most likely cause. Gut infections in general can cause both.
Some people are also very bad at digesting specific foods. I cannot eat oats, at least if I want to have social contacts the next 2 days.