Turmeric certainly stains your kitchen too, at least that's what it's done to mine. Dietary absorption of curcumin is abysmally low however it is improved somewhat by including piperin in the dish. Piperin coincidentally enough is what gives black pepper it's taste and so is commonly found in curry mixes!
"You can demonstrate the purpose and limits of human digestion with a simple experiment: eat a steak with some whole corn kernels, and see what comes out the other end. It won’t be the steak."