The zinc helped with adhesion and was probably safe so long as people used moderate amounts of cream. Indeed, the human body needs small amounts of zinc to function. But some people ended up using much larger amounts, and they began to develop the kind of nerve damage associated with excess zinc.
Johnny Howell of Winston-Salem, N.C., who was using a tube of Poligrip a week, had to quit his job as a car mechanic and now needs a walker to get around his house. He is 53 years old. Rodney Urbanek, another Poligrip customer, began using a walker in 2007, at age 63. He died a year later, apparently a result of a copper deficiency from "zinc overload," according to his autopsy.
Now, the science here still is not completely clear. One researcher I interviewed said he wanted to see more evidence before being confident that Poligrip was the problem. Other researchers said they thought the causal chain was clear. Poligrip has a lot of zinc. Too much zinc causes copper deficiency. A lack of copper causes nerve damage.
Either way, the evidence has become strong enough that last month GlaxoSmithKline -- which also makes Tums, Nicorette and the country's top-selling asthma drug -- stopped making the version of Poligrip with zinc, after having previously resisted just such a move. In Japan, responding to regulators' concerns, the company has also recalled from stores any remaining zinc-infused cream.
All of which makes you wonder: did it have to come this?
Every society needs to make a choice about how to prioritize consumer safety. If you try too hard to avoid problems, you can end up stifling daily life. Outlawing gasoline, for instance, would doubtless reduce pollution and respiratory disease, but no one is suggesting such a step. Europe, with its hostility to genetically modified foods, arguably errs on the side of being too cautious about chemicals and other such substances.
But the United States clearly seems to be on the other side of the line. We are not taking toxic risks seriously enough.
Several common diseases, like certain cancers and developmental disorders, have been rising in recent decades, and scientists are not sure why. In some cases, evidence suggests chemicals may be the reason.