Note: I am the author of "It's Probably Not Lithium."
That SMTM post only addresses 5 of the ~17 studies about food lithium concentration that I mentioned in my post. It ignores several studies that did not use ICP-MS to measure lithium and found very low concentrations of it in food.
Moreover, as samatman mentioned, the post doesn't seem to understand that wet and dry weights are substantively different measures, and cites Magalhães et al. (1990) and Hullin, Kapel, and Drinkall (1969) as if they were reporting wet weight measurements of lithium, when they're reporting dry weight measurements. This makes a huge difference, because watercress (measured in Magalhães et al. (1990)) and lettuce (measured in Hullin, Kapel, and Drinkall (1969)) are both over 90% water by weight.
So that post is largely just based on cherry-picking and misrepresentation of studies.
Moreover, as far as I could tell, only *two* of their sources *actually attempt to estimate dietary lithium intake*, whereas almost all of my ~17 sources do. This is important because the SMTM post references a lot of studies that are not available on the internet, so we don't know whether they reported lithium concentration in dry or wet weight of food. Moreover, one of those sources based its estimation on hair lithium concentration rather than actual food measurements, using a regression model whose accuracy at low levels of dietary intake is unknown.
The vast majority of studies that actually attempt to estimate dietary lithium intake based on lithium concentration in food estimate it to be lower than 100 mcg/day, regardless of methodology. The only exceptions I am aware of are two studies from Manfred Anke.