I've been learning a little more about cultivating white asparagus. While it is growing, dirt gets heaped over it, limiting the sunlight it receives. It does not develop chlorophyll, and so it never turns green. Strangely enough, the white asparagus stalks I've seen are really thick, at least twice as thick as those of green asparagus. This is interesting, because if they grow without sunlight, I would expect them to be weak and spindly, not thick and strong.
I also learned that asparagus has a large amount of purines, and purines are metabolized into uric acid, so people who have gout (uric acid crystals built up in the tissues, especially the joints) may experience an attack of gout after eating it. But on the other hand, purine-rich plant foods are less likely to cause gout than meats that contain high levels of purines. So unless you already have gouty arthritis, the extra purines are no reason to avoid asparagus! I hope this springtime brings you plenty of asparagus, whether green or white, or even purple!