The latest dizzy-sounding Hollywood craze has new mothers gobbling their baby’s placenta after giving birth. And now RadarOnline.com can reveal the celebs who’ve done it include Kim Kardashian, Alicia Silverstone, and Chrissy Teigen, according to sources. While star moms swear it helps prevent horrific postpartum depression and speed postnatal recovery, the medical community has delivered its diagnosis: it’s not necessarily a good idea — and can even be dangerous! Actresses Nikki Reed, Mandy Moore, January Jones, and Silverstone, and sisters Kim and Kourtney Kardashian had their placentas drie…