So Martha Stewart is making rhubarb desserts today – a fool (for April Fool’s Day, hah) and a grunt. But she said one thing that caught my attention:
The leaves are deadly poisonous … They are toxic, oxalic acid and you can really die from it. And you notice in the fields, at the farm, the horses never go near, the chickens, nobody goes near the rhubarb.
While it’s true that rhubarb leaves are poisonous the cause isn’t oxalic acid, which is found in many foods, including cocoa, spinach, carrots, and berries. Spinach contains enough to all but wipe out the calcium found in the vegetable, because oxalic acid combines with the calcium to form calcium oxalate, an insoluble compound that can build up and form stones in the kidney or gallbladder. If oxalic acid was the only toxin at work in rhubarb leaves, it would take several pounds to kill you.
It is possible, however, that there’s a second compound at work in rhubarb leaves that works with the oxalic acid to make them toxic. One suspect is a form of anthraquinone glycoside, which is present in rhubarb roots and has been used in traditional medicine as a laxative. The anthraquinone glycoside(s) in rhubarb leaves may work in tandem with the oxalic acid to have a toxic effect, although there doesn’t seem to be any hard evidence to back that up.
I have no idea why I posted this other than that I like rhubarb.