The Mormon Lord is Wrong About Coffee

Mormons believe that it is wrong to drink coffee. This doctrine is stated in Doctrine and Covenants 89 in a section called the Word of Wisdom. The Word of Wisdom is described by the LDS organization as:

A law of health revealed by the Lord for our physical and spiritual benefit. In this revelation the Lord commands us not to use alcohol, tea, coffee, tobacco, and harmful or habit-forming substances, and promises blessings for obeying this commandment.Defintion from mormon.org

Why, in obedience to what the Mormon Lord has given as "a law of health" intended to yield "physical benefits", have Mormons been drinking Postum instead of coffee (which has been shown to be more beneficial than harmful)? According to the Salt Lake Tribune, Postum is on the way out, and it turns out is actually bad for you anyway:

Recent government health studies have listed Postum as having high levels of acrylamide, a substance that can cause cancer and reproductive problems in animals and act as a neurotoxin in humans. But even such findings have not deterred fans.Salt Lake Tribune, "Mormons mourn Postum's passing -- Props on the alliteration, guys.