The Good News About Multivitamins
There was good news about nutritional supplements recently. Very good news. A good study–a very good study–showed remarkable benefit associated with the use of multivitamin supplements. In short, this new study indicates that men who took a modest potency multivitamin multimineral supplement reduced their risk of cancer, overall, by eight percent.
An overall eight percent reduction in cancer is not something to take lightly. Especially when it merely involves taking a basic multivitamin supplement. What a large benefit from so small an effort. Why wouldn’t everybody support the idea of taking, at least, a basic multivitamin multimineral supplement every day?
You would think that common sense alone would support the idea. We know how important vitamins and minerals are to our health. We know that a deficiency of one or more of these vital nutrients can lead to life-threatening illness. We know that, for many reasons, many of us do not eat as nutritious a diet as we should. So why would anybody argue against a daily multivitamin multimineral supplement? Why would we even need to “prove” the value of daily supplementation?
That’s a good question. But it seems that “proof” is necessary, but elusive. There is something about ascribing significant health benefits to nutritional supplements that irritates certain people to no end. Health problems, according to these folks, should only be treatable and preventable by a balanced diet, exercise, and medications. Any implication that nutritional supplements belong in that list is met with consistent resistance and scepticism.
A good example of this was the way this recent study was reported in The New York Times. When a negative study comes out pertaining to nutritional supplements, it is given headline status. When a positive study, such as this one, is published, however, it does not receive similar treatment. Instead, it’s importance is minimized. In this case, the positive study about multivitamins reducing the risk of cancer by 8% was covered in an article by Roni Caryn Rabin, titled “Curbing the Enthusiasm on Daily Multivitamins.” The first sentence of the article poses the question “can you reduce your risk of cancer by taking a multivitamin every day?
The article continues “Last week, Boston researchers announced that one of the largest long term clinical trials of multivitamins in the United States–encompassing 14,000 male physicians 50 and older, and lasting over a decade–found that taking a common combination of essential vitamins and minerals every day decreased the incidence of cancer by 8 percent, compared with a placebo pill.”
The article continues with more positive news: “. . . The researchers also looked for side effects and found that daily vitamins caused only minor problems, like occasional skin rashes.
“Even though an 8 percent reduction in the overall cancer rate is fairly modest, Dr. Demetrius Albanes, senior investigator at the National Cancer Institute, said the potential public health implications were vast. “If you think of the hundreds of thousands of new cases of cancer every year, 8 percent can add up quite a bit,” he said.”
Then, however, the author launches a detailed explanation as to why we should not let this positive study lead us to make the mistake of thinking this justifies taking multivitamin supplements. She points out that “previous studies have yielded decidedly mixed results.” She points out that “Current federal dietary guidelines and American Cancer Society recommendations encourage people to eat a balanced diet rich in fruits and vegetables.”
“Until now,” she states, “the consensus has been that there is insufficient scientific evidence to justify taking a multivitamin to prevent cancer or other chronic diseases.” Note that she used the term “until now.” Interesting choice of words.
She continues with a listing of additional cautionary references. She reminds us of the review by the National Institutes of Health in 2006 which “concluded that evidence was ‘insufficient to prove the presence or absence of benefits from use of multivitamin and mineral supplements.’ Again, note the actual terminology: “presence or absence.” Then she reminds of the recent studies that cast doubt on vitamin D and Calcium supplements. She neglects to mention, of course, that these studies have been met with strong criticism and are considered very controversial. She also, it seems, has found it necessary to support her argument by departing from what was initially a critique of daily multivitamin supplements to studies dealing with individual nutrients, at higher dosages.
Thank goodness we have people like Ms. Rabin, and publications like The New York Times out there to protect us from making mistakes such as this.
One of the interesting comments in her article was “Generally speaking, people who take vitamins are a relatively healthy bunch to begin with, experts say. They tend to eat a varied and healthful diet, watch their weight and be physically active. It’s not always clear that the benefits they attribute to vitamins actually result from the pills.” This is very true. But why doesn’t it work both ways. It may not always be clear that the benefits attributed to vitamins actually result from the “pills,” but it is also true that it may not always be clear that negative findings are directly related to the “pills” as well.
The next paragraph in her article confirms this. “There’s a mystique about vitamins, that vitamins are some type of magical ingredient,” said David G. Schardt, senior nutritionist for the Center for Science in the Public Interest, an advocacy group in Washington. “There is a kernel of truth in that, because vitamins are essential to life. But that people will live longer or healthier lives if they take vitamins or eat foods fortified with vitamins–that’s difficult to prove.”
Yes, it’s difficult to prove, and difficult to disprove.
This is not to say we should ignore negative studies. We can learn from negative studies as well as from positive studies. The finding that smokers given high dosages of synthetic beta carotene seemed to experience greater incidence of lung cancer rather than lower incidence, as expected, is not something to be dismissed. There are lessons to be learned from negative findings like this. But we need to look at the full picture. And we need to factor in a large dose of common sense.
Yes, there is the danger that some people might make the “if a little is good, a lot has to be better” mistake. And yes, the benefit of certain nutrients in multivitamin supplements may be more significant, even therapeutic, for those deficient in that nutrient. But we don’t know if we are deficient in one nutrient or another. We don’t know if we are subclinically deficient, i.e. not sufficiently deficient to cause disease, but at levels less than optimal. As they say in the study, a daily multivitamin appears to be safe. The upside is great, and the downside is minimal. Why is taking a multivitamin supplement such a threat?
Those who are so concerned that we might rely on nutritional supplements, rather than a healthy diet rich in fruits and vegetables, act as if the role of diet is somehow “proven” and the role of supplements is not. Is this true? Perhaps not. Here is an excerpt from the actual study, Multivitamins in the Prevention of Cancer in Men: The Physicians’ Health Study II Randomized Controlled Trial, JAMA. 2012;():1-10. doi:10.1001/jama.2012.14641.
“Multivitamins are the most common dietary supplement, regularly taken by at least one-third of US adults. The traditional role of a daily multivitamin is to prevent nutritional deficiency. The combination of essential vitamins and minerals contained in multivitamins may mirror healthier dietary patterns such as fruit and vegetable intake, which have been modestly and inversely associated with cancer risk in some,3 but not all, 4,5 epidemiologic studies.” [emphasis is mine]
Clearly, it seems, the evidence for fruit and vegetable intake is not “proven” either. There are those two references: 4. Löf M, Sandin S, Lagiou P, Trichopoulos D, Adami HO, Weiderpass E. Fruit and vegetable intake and risk of cancer in the Swedish women’s lifestyle and health cohort. Cancer Causes Control. 2011;22(2):283-289. 5. Hung HC, Joshipura KJ, Jiang R, et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst. 2004;96(21):1577-1584
Getting back to the study, “The Physicians’ Health Study II is the first clinical trial to test the affects of multivitamins on a major disease such as cancer,” said lead author J. Michael Gaziano, MD, chief of the Division of Aging at Brigham and Women’s Hospital and an investigator at VA Boston. “Despite the fact that more than one-third of Americans take multivitamins, their long-term effects were unknown until now.”
“Researchers had nearly 15,000 men over the age of 50 take either a multivitamin or a placebo every day for more than 10 years. The men self-reported a cancer diagnosis, and researchers confirmed the diagnosis through medical records. Researchers found the group taking a daily multivitamin had an 8 percent reduction in total cancer compared with the group taking the placebo. They also found a multivitamin was associated with an apparent reduction in cancer deaths.
“Study co-author Howard D. Sesso, ScD, an associate epidemiologist in the Division of Preventive Medicine at Brigham and Women’s Hospital said, “Many studies have suggested that eating a nutritious diet may reduce a man’s risk of developing cancer. Now we know that taking a daily multivitamin, in addition to addressing vitamin and mineral deficiencies, may also be considered in the prevention of cancer in middle-aged and older men.”
“Researchers point out that it is not clear which specific vitamins or minerals in a multivitamin may be responsible for the reduction in cancer risk. Also, it is not known if the results can extend to women or to men younger than the age of 50. Researchers plan to follow up with study participants to determine the affect of a daily multivitamin on cancer over an even longer period of time.
“A similar study is examining the affect of daily multivitamin use on cardiovascular disease risk. Results of that study will be announced at the American Heart Association Scientific Sessions in early November.” (As reported in ScienceDaily, Oct. 17, 2012)