title_body: Is coffee blocking the body from absorbing nutrients?
upvoted_answer: In a collaborative study at Creighton University in Nebraska and the University of Miami, Florida, researchers showed that caffeine may interfere with vitamin D absorption. The results, published in the "Journal of Steroid Biochemistry and Molecular Biology," demonstrated that the higher the level of caffeine, the more it interfered with vitamin D absorption. The study suggested that caffeine did this by reducing the expression of vitamin D receptors on osteoblasts in the body -- the cells responsible for producing bone.
  
  http://www.direct-ms.org/pdf/VitDGenScience/Caffeine%20Vit%20D%20receptor%2007.pdf