The July 2008 Ensign has an article titled “Cancer, Nutrition, and the Word of Wisdom.” I think it is ill-advised for several reasons.
We should not be following the Word of Wisdom because scientists have identified pragmatic benefits from it. We should be following it out of obedience to the word of God and the doctrines of the Church. A little thought experiment might illustrate why this is so: imagine the following headlines in the newspaper tomorrow:
Scientists Prove Cigarettes Lengthen Life
Leading Nutritionist: Meth Users Don’t Get Cancer
AMA Endorses Beer to Prevent Birth Defects 
If your testimony of the WoW had been based on Ensign articles explaining its scientific benefits, I think you might be tempted to jump ship when faced with contradictory evidence. If your testimony of the WoW was based on a spiritual witness that it is a commandment for modern saints, you’d see those headlines and then turn to the funnies with a shrug.
I think the “science shows our faith is right” approach is dangerous primarily for a more insidious reason, however: it encourages us to expect scientific backing for the tenets of our faith. And so when the sociologists can’t show that day care is harmful and the archaeologists can’t find any Nephites and the family scientists discover that children raised by same-sex parents turn out just fine, thank you very much, confusion is sown in people who were raised on a steady diet of the scientific “evidence” for our beliefs and practices. This may not seem terribly important to those of you with strong, well-founded testimonies, but as a convert, I can see the danger in encouraging people to think that science has (or soon will) prove the veracity of all of our doctrines and practices. It isn’t going to (in our lifetimes) and expecting it to is to build on the sandiest of foundations.
That’s my objection to the approach of the article, but I had problems with some of the specifics as well. At one point the author writes, “From the perspective of medical science, most investigators who have examined the effects of caffeine suggest that caffeinated beverages should not be consumed in large quantities.” Of course, he has to say “large quantities” because most investigators would not agree that very small quantities would have harmful effects. As we all know from the overblown “rat studies” large enough quantities of pretty much any innocuous thing will do you in. But what does this have to do with the WoW, which prohibits all hot drinks? (And I won’t even get into the hot drink/caffeine issue here.) In this case, the scientific evidence most definitely does not support the WoW’s complete prohibition on hot drinks, so why even mention it?
Even worse is the section on alcohol. The author notes that alcohol is implicated in an increased risk of some cancers. OK, fine. But google “health benefits of red wine” and then tell me if you think that his brief paragraph can be called representative of the current state of the research on health consequences of alcohol consumption. (Short answer: no.) It is unethical to cherry-pick a few studies that suggest a link between alcohol consumption (in general) and (a few types of) cancer while ignoring the much larger body of evidence that suggests that not only is red wine not harmful, but that it has enough health-promoting benefits that many of his colleagues recommend daily consumption of red wine in order to ward off cancer and other health problems.
The only thing worse than linking gospel principles to science is linking them to bad science.
And I can’t resist ending on a flippant note: Why on earth would an LDS person trot out studies showing that faithful Saints live longer than average? I thought our goal was to return to God’s presence. Are you telling me that following the commandments delays that? Problematical, I say.
 When my mother was pregnant with me in 1974, her OB/GYN told her to drink beer. I can’t remember what reason was given, but it was all very scientific.