It's the fat that is needed to assimilate the beta carotene.... A is a fat soluble vitamin.... I'm not clear on the calcium requirement here. I know that oxalic acid in spinach binds calcium and I believe it is the acid that gives the strange feeling on the teeth..... Oliva ----- Original Message ----- From: "Alex Shvartsman" <[log in to unmask]> my teeth always fee fuzzy when eating spinach. Why is that? Also can some one elaborate on why calcium is needed when eating Spinach?