As the iconic Tim "The Tool Man" Taylor would say, "[guttural grunt], more power."
If I'm properly remembering Home Improvement, things rarely went awry for Taylor and his wife Jill. His North Star was the simple, relentless pursuit of the twentieth-century American "more is more" ethos. Taylor owned a multi-story house, had three stylish boys, a happy marriage, and a career that afforded him both celebrity and pursuit of his passion. Meanwhile the family's painfully levelheaded neighbor, Wilson, squandered most of his time clinging to eccentric cultural anachronisms alone in his backyard. It was strongly implied that he had lost the bottom half of his face in some sort of terrible accident.
The moderate Al Borland was also perpetually drab, surpassed by Taylor in every quantifiable metric of success.
Taylor is not America's Doctor today, though. (America's Doctor is of course Dr. Mehmet "A Revolutionary New Way to Live Years Longer: It's Red Palm Oil" Oz.) On the whole, twenty-first century medicine is ushering in a revival of moderation. This weekend, Dr. Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia, wrote a fact-heavy piece in the Opinion section of The New York Times, "Don't Take Your Vitamins." It was the most popular article on the Times' site.
I know what it's like to be reduced to a headline. People sometimes put articles on their Facebook walls without reading past the headlines, I hear. Offit's actual point is more nuanced, if no less reactionary: Multivitamins are not a panacea; more is not always better; more is sometimes quite bad. Some of the anti-supplement data he cites is compelling:
In a study published in The New England Journal of Medicine in 1994, 29,000 Finnish men, all smokers, had been given daily vitamin E, beta-carotene, both or a placebo. The study found that those who had taken beta-carotene for five to eight years were more likely to die from lung cancer or heart disease.
Two years later the same journal published another study on vitamin supplements. In it, 18,000 people who were at an increased risk of lung cancer because of asbestos exposure or smoking received a combination of vitamin A and beta-carotene, or a placebo. Investigators stopped the study when they found that the risk of death from lung cancer for those who took the vitamins was 46 percent higher.
Then, in 2004, a review of 14 randomized trials for the Cochrane Database found that the supplemental vitamins A, C, E and beta-carotene, and a mineral, selenium, taken to prevent intestinal cancers, actually increased mortality.
Another review, published in 2005 in the Annals of Internal Medicine, found that in 19 trials of nearly 136,000 people, supplemental vitamin E increased mortality. Also that year, a study of people with vascular disease or diabetes found that vitamin E increased the risk of heart failure. And in 2011, a study published in the Journal of the American Medical Association tied vitamin E supplements to an increased risk of prostate cancer.
Finally, last year, a Cochrane review found that "beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A."
When you put it that way, vitamins look bad. Beta-carotene, very bad. The fat soluble vitamins (A, D, E, K), as a rule of thumb, are the easiest to get too much of. Still reductive notions swaying perception too far against nebulous notions of vitamins is also bad. Everything we knew is not wrong.
First, talking in aggregate about all vitamins (which is like lumping "medications" as one thing) in binary good-or-bad terms misses all the points. We still don't know the exact ideal amounts of many vitamins, though we know more about some than others. For example, just three months ago, the U.S. Preventive Services Task Force reversed its position on vitamin D and calcium supplements for postmenopausal women. Michael LeFevre, chair of the task force that made the statement, said, "What we're saying is that a practice that we have commonly used for years -- literally, years -- routinely in postmenopausal women just doesn't work."
Likewise, as Offit says, presently "respected organizations" do not recommend multivitamin supplements for "otherwise healthy" people. The official position of the National Institutes of Health is, "The present  evidence is insufficient to recommend either for or against the use of multivitamins by the American public to prevent chronic disease." Still many people do benefit from multivitamins. "Otherwise healthy" in this case does not include, for example, those on limited diets, some elderly adults, people who've had gastric bypass, or people who drink a lot; all of whom are relatively prone to vitamin deficiencies.
Similarly while vitamin A supplementation is not recommended in industrialized countries -- and can be outright dangerous to pregnant women -- the World Health Organization does recommend it in resource-poor places. Vegans may need to be on B12, but it is not recommended for most people. Vitamin C supplements, too, which are commonly taken in hopes of warding off impending colds, are not recommended as they have not actually been shown to work.
There is also the concern that deficiencies don't just manifest as overt syndromes like scurvy, but sometimes as more insidious pathologies. They have been tied in limited research to cancers, high blood pressure, and atherosclerosis. (Likewise vitamin excess has been tied to many of the same things.) Still the USPTF maintains that there's "not enough evidence" to blanket-recommend that we take (or that we do not take) vitamins A, C, E, or multivitamins, folic acid, or antioxidant supplements for purposes of preventing cancer or heart disease. Expect more research on all of that, particularly in high-risk patients.
One of the most important points to note where supplementation is very recommended is folic acid in pregnancy, which is necessary for normal cell division, as a supplement to all women trying to conceive -- sometimes to all women of childbearing age. (True you can get pregnant at 60 now with IVF, but the point is to address cases of unplanned pregnancy, where neural tube defects like spina bifida can result from insufficient folate before the woman even knows she's pregnant and thinks to start taking prenatal vitamins).
Bottom line, we understand the majority of people to be best off without any vitamin supplements. Just because they are non-prescription and still live inside a "health halo," vitamins are not harmless. They could shorten or extend your life; at this point, taking vitamins randomly is metabolic roulette. So, not to sound like the caveat at the end of a pill commercial, talk to your doctor about vitamins -- just like you would about prescription medications -- before waving any sort of pro or anti-vitamin flag. Not everyone needs the same things, and more doesn't mean better. Be the Al Borland of nutritional supplements.