On the off chance that a reader misunderstands, lecithin isn't just a naturally occurring emulsifier. It's a particularly good source of phosphatidylcholine. Choline, a methyl donor, is important for people who have methylation issues - and there's some evidence that the other option, choline bitartrate, is associated with TMAO. Personally, I suspect that this is due to the bitartrate being less bioavailable, so more of it in the gut leading to bacterial production - but I've seen no studies. (bio-trivia: the gut makes TMA from choline and/or carnitine; the liver then converts it to TMAO)

Also, the liver uses choline as part of the process of exporting fat - a low choline diet can result in a fatty liver. There's been a good bit of lab work on this (mice). Not sure about humans. I don't expect anything randomized due to ethical issues.

Just a thought...