Sauropus androgynus (L.) Merr. Induced Bronchiolitis Obliterans: From Botanical Studies to Toxicology (Katuk)
Martin Price :
"I periodically check for updates on katuk safety. This 2015 article is the most thorough literature review of positive benefits and negative toxicity that I've seen. (I learned that "katuk" is the/an Indonesian name.) A lot more research has been done since the big publicity from Taiwan around 1997 from lung damage caused by a bizarre diet craze. Leaves were run through a juice expeller and the pure juice was mixed with fruit juice and drunk. Amazingly I've never seen in any report how much concentrated juice and from how much weight of leaves was being recommended daily. I also never read other details of the diet, like whether this was the main thing they ate/drank or if it was a small amount taken more like medicine. That is an obvious detail that should have been in every article about the subject. It might be possible to eat enough katuk leaves (or a lot of anything) to eventually cause some kind of health issue.
My one big concern is that not until the final paragraph do they mention that the lung damage in Taiwan was from drinking katuk juice, not whole leaves That makes a world of difference. The most important nutritional advice I give anyone regarding (especially) perennial vegetables is to eat like the goat (a browser that won't eat too much of anything) and not like the cow (a grazer that will happily keep eating the same thing.) I would not consider drinking katuk juice nor eating katuk every day or in unusually large quantities. The same would go for any leafy perennial vegetable. A plant only becomes a perennial if it has an arsenal of substances that would be toxic to a bug or fungus eating nothing but the leaves of that plant. "