Bummer about them vitamins…again

ResearchBlogging.orgI have to say, this is getting monotonous.

Let me back up a minute. One of the most common beliefs among users and advocates of “complementary and alternative” medicine (CAM) is that supplementation with vitamins will have all sorts of beneficial health effects. True, this belief is also pervasive among people who wouldn’t go to an acupuncturist if you held a gun to their head, but it has become most associated with CAM. That this is so can actually be viewed as evidence of just how successful CAM activists have been in completely yoking all manner of lifestyle interventions to prevent or treat disease as somehow being “alternative” rather than, as they really are, science- and evidence-based. Of course, diet and exercise are the Trojan horse that CAM advocates hope to get the guardians of scientific medicine to bring into the fortress. When that happens (actually it is happening), diet and supplement warriors will leap out and open the gate of the castle to let in all the woo whose practitioners have coopted potentially science-based lifestyle interventions. One thing that should be noted is that in CAM world, diet and exercise are often not considered enough. No, it’s not considered adequate to eat enough fruit and vegetables and to avoid fatty foods. Oh, no. You also have to swallow all manner of vitamin supplements, because, or so we are told, they will prevent all manner of disease.

The concept that vitamin supplementation might prevent cancer is not in and of itself an unlikely idea. Diet has a powerful effect on health, and it is not unreasonable to hypothesize that supplementation with certain vitamins might have beneficial health effects. For example, although I used to be very skeptical about it, I’m starting to think that there might just be something to the hypothesis that vitamin D supplementation can decrease the risk of colon and breast cancer if the appropriate amount is taken to raise the blood level to a certain range. (Perhaps that will be the topic for another post, but in the meantime Dr. Len and Ed Yong have written good primers on the suggestive but muddled state of the evidence with regard to whether vitamin D prevents breast cancer.) While I haven’t gone whole hog and started advocating that my patients take vitamin D supplementation, given that it’s pretty clear that a certain target blood level must be not only reached, but verified, or started taking it myself, I certainly will if more evidence clarifies the picture better. In fact, from my perspective, the case for vitamin D is actually harmed by idiots like Mike Adams routinely bringing home the crazy by painting it as some sort of miracle vitamin that prevents and cures all manner of cancer, because his infectious idiocy is tainting what may well be a science-based preventative measure.

Other studies of vitamins and cancer have been a lot more disappointing. One recent study examining the effects of selenium and vitamin E on preventing prostate cancer had to be stopped early because there was no benefit and a hint that there were more cancers in those taking vitamin E and more diabetes in those taking selenium. And just this week, a new study has been published that has also found no benefit in preventing cancer or heart disease due to routine vitamin supplementation. The study, using data from the Women’s Health Initiative and entitled Multivitamin Use and Risk of Cancer and Cardiovascular Disease also found no benefit from multivitamin supplementation in overall survival.

The first thing you need to know is that the Women’s Health Initiative is a massive–and I do mean massive–ongoing study of women’s health. Begun in 1991, it is one of the largest prevention trials ever undertaken and addresses the most common causes of death and impaired quality of life in postmenopausal women. The WHI consists of randomized trials and an observational trial, and its three components include:

  • a randomized controlled clinical trial of promising but unproven approaches to prevention;
  • an observational study to identify predictors of disease;
  • a study of community approaches to developing healthful behaviors.

Indeed, my medical center is one of the WHI centers, and I happen to know the WHI coordinator for our site. Numerous publications have resulted from the WHI, spanning areas of estrogen supplementation, the effect of diet on the risk of cancer, and even the development of methodologies for studying such questions. The current study was part of the WHI in the following manner:

The WHI is a study of postmenopausal women’s health and risk factors for cancer, heart disease, and skeletal health.It was designed as a set of randomized controlled CTs and an OS. Women were eligible for participation if they were 50 to 79 years of age at screening, postmenopausal, and likely to live in close geographic proximity to 1 of 40 WHI clinical centers for at least 3 years. Women were excluded for medical conditions with a predicted survival of 3 years of less, for conditions limiting adherence or retention (eg, alcohol or drug dependency and dementia), or for active participation in any other intervention trial in which participants were individually randomized to a control or intervention group. The CTs (N = 68,132) included 3 overlapping components: the hormone therapy trials (N = 27,347), the dietary modification trial (N = 48,835), and the calcium and vitamin D trial (N = 36,282). Eligible women could be randomized into 1, 2, or all 3 of the CTs. Trial arm assignment was randomly designated (1:1 for the hormone therapy and calcium and vitamin D trials; 40% were assigned to low-fat intervention and 60% to usual diet for the dietary modification trial). Women who were ineligible or unwilling to join the CTs were invited to join the OS, as were those who were specifically recruited for the OS (N = 93,676). The CT women attended baseline and annual clinic visits. The OS women attended baseline and 3-year clinic visits and completed all other annual study activities by mail (eg, medical history and lifestyle-exposure updates). The women were followed up for a median of 8.0 years in the CTs and 7.9 years in the OS. All WHI participants provided written informed consent, and institutional review board approval was obtained at each of the 40 WHI clinical centers and at the Clinical Coordinating Center at the Fred Hutchinson Cancer Research Center, Washington. This report is based on data from 161,808 women in both the OS and the CTs; 2 women were excluded because of incomplete dietary supplement information.

The first thing that needs to be understood is that this “sub-study” of the WHI is not a randomized, controlled trial. Rather, it is an observational study using the 161,808 women in the WHI. However, it is a very, very good observational study. One aspect of it that should tell you just how good the data collection is in this trial was the fact that data from only 2/161,810 women had to be excluded from the final analysis due to incomplete recording of dietary information. That is truly an astounding feat. The way this was accomplished was that, during the followup, detailed information was routinely collected about vitamin and supplement use. Also, the women in the study were asked to bring their bottles with them so that their doctors could record exactly what they were taking, at least as closely as is possible in a study of this type. Combine such a large number of women with such detailed record-keeping, and you have about as powerful an observational study as is possible.

What the investigators found, unfortunately (and I do mean unfortunately because I would actually like to see some sound evidence that taking a multivitamin could prevent heart disease and cancer), was nothing. Nada. Zip. Zero. There was no association between cancer and vitamin or multivitamin supplementation, no association between heart disease and supplementation, and no association between overall survival time and supplementation. It was about as resoundingly negative a study as there is. Even subgroup analysis, looking at different ages, other risk factors (such as smoking) and duration of supplementation, couldn’t tease out a positive result. There were suggestions that older women taking multivitamins may have had a slightly lower risk of endometrial cancer and that obese women taking vitamins might have slightly lowered their risk of breast cancer, but younger women taking vitamins actually appeared to be at a slightly higher risk of death.

Of course, this study was not without limitations. As strong as its numbers and rigorous data collection made it, it is still an observational study. There could be confounding factors; for example, often women who take supplements engage in other behaviors, such as exercism that could improve their health. This study tried to control for such potentially confounding factors, but in observational studies investigators can never completely rule out the possibility of residual confounders. Perhaps the most relevant potential weakness of the study is that its duration was only 8 years. However, for many of these measures, such as heart disease and cancer, in women over 50 eight years should be enough to detect significant differences. Be that as it may, these women will continue to be observed, and, I’m sure, there will be more reports after several more years; if a later difference in these diseases or in overall survival exists, it is likely that the WHI will eventually detect it.

The authors conclude:

In conclusion, the WHI CT and OS cohorts provide convincing evidence that multivitamin use has little or no influence on the risk of cancer or CVD in postmenopausal women. Nutritional efforts should remain a principal focus of chronic disease prevention, but without definitive results from a randomized controlled trial, multivitamin supplements will not likely play a major role in such prevention efforts.

And, in a news interview, the study’s lead author states:

The study’s lead author, researcher Marian Neuhouser of the Fred Hutchinson Cancer Research Center in Seattle, offered this advice: “Get nutrients from food. Whole foods are better than dietary supplements,” Neuhouser said.

What this study shows is that routine vitamin supplementation is probably not necessary for most people. Eating a decent diet generally will provide the vitamins and nutrients needed. That is not to say that science does not support vitamin supplementation in specific, targeted cases, for example, in recommending that pregnant women take folate supplementation. It is possible that vitamin D supplementation (or at least increading the RDA for vitamin D) may be recommended in the future, especially for people living in northern climates with little sun, based on science.

However, reasonable, minimal, targeted vitamin supplementation in people who have adequate diets is not what CAM is all about. It’s about taking megadoses of various vitamins and supplements. It’s about taking what is characterized as “natural” supplements as opposed to big pharma-produced “artificial” vitamins. it never seems to enter the minds of such people that there is no more natural way to get the vitamins you need than through their food, but logic and science were never the strong suit of many CAM advocates.

Speaking of someone for whom logic and science are not strong suits, predictably that king of paranoid conspiracy mongering woo, Mike Adams at NaturalNews.com, has already fired off a counterattack. True to form, it is full of idiotic sound and fury, signifying nothing. Also true to form, it has labeled the WHI study a “big pharma attack” on “natural remedies.” I will, however, express amazement (and relief) that Adams actually managed to restrain himself from making any references to Hitler, Nazis, or the Third Reich in attacking this study. I can picture him there in front of his keyboard, his right forefinger twitching over the letter “H” alternating with twitching over the letter “N” because he so wanted to type either “Hitler” or “Nazi,” but with an iron will he restrained the stupid crazy just that much. Bravo!

Even so, this bit broke my irony meter:

There was no quality control in the study. Since no multivitamins were given to women, there was no quality control at all. Did these women take cheap, synthetic vitamins bought at Costco? Or did they take quality supplements from better sources? Nobody knows because it wasn’t tracked!

The reason my irony meter has once again been reduced to a blazing, molten, sputtering pile of metal and plastic is that supplementation, at least as it is advocated by Adams and his ilk, is inherently unnatural. There is no more natural way to receive one’s nutrients than through food. It is not “natural” to desiccate plants and pack them into capsules. It is not “natural” to isolate the chemicals that are vitamins and pack them into capsules. Adams is one to talk about “cheap, synthetic” anything, especially since there is no evidence that those “cheap, synthetic” vitamins are any different from the over-priced ripoffs that so many health food stores sell. It is not “natural” to desiccate and grind up animal glands to make supplements as advocates of the “alternative” medical modality known as “live cell therapy” do.

It’s also amusing how Adams froths at the mouth because he thinks the study so incompetently designed that it didn’t bother to actually record what patients took. In fact, the bottle labels were examined, and the ingredients of each multivitamin supplement painstakingly recorded by WHI research staff:

Dietary supplement data were collected during in-person clinic visits. Women brought supplement bottles to the baseline clinic visit and to annual visits thereafter in the CTs and to the baseline and 3-year visits in the OS. A standardized interviewer-administered 4-page form was used to collect information on multivitamins, other mixtures, and single supplements. For the multivitamins, separate sections were provided on the form to designate multivitamins, multivitamins with minerals, or stress supplements. Staff members directly transcribed the ingredients for each supplement.

But Adams also seems to think that the WHI investigators are even more incompetent than that:

  • Most people SAY they take multivitamins, but don’t. If you ask most people, they will TELL you they eat healthy, and that they take multivitamins. But in reality they don’t. Most people greatly exaggerate the description of their own health habits.
  • Multivitamin consumption FREQUENCY was not accurately measured. There was no ability of this study to reliably measure how often consumers actually took their multivitamins. Did they take them once a week? Once a month? Once a year? Even taking them once a year would have counted in this study as “taking multivitamins.” Gee, no wonder the results showed no improvement…

In effect, this study did not measure the effects of multivitamins on cancer and heart disease. What it really measured was the degree to which people exaggerate their own claims of health habits, and the degree to which the mainstream media so easily falls for junk science.

Mike must really think that the WHI investigators are a bunch of incompetent boobs, drooling as they interviewed patients and recorded data, or he’s lying because he wants to smear them so that his readers think they are incompetent boobs. Adams is also just plain lying when he says that taking a supplement “once a year” or even “once” counts. Does he really think there were no measures, no validation, no attempts to verify that self-reported supplement intake actually corresponded to what participants actually did take? In fact, the WHI has methodology in place to estimate the accuracy of participant-reported dietary habits, and these have even been validated and published:

Staff members directly transcribed the ingredients for each supplement. They also asked participants about frequency (pills per week) and duration (months and years) of use for each supplement. Only supplements used at least once a week were recorded, but there was no limit on the total number of supplements allowed. A validity study of these procedures demonstrated that correlations of interviewer-transcribed doses with data from photocopied labels ranged from 0.8 to 1.0.

In other words, the methodology in this study had been tested before and been found to be at least 80% reliable. Take that, Mike! Also, the investigators looked for correlations between duration of supplement use and health benefits. If there were a true effect, one would expect that longer supplement usage would result in a greater effect. No effect was found.

Of course, to Mike, it’s all a big pharma conspiracy:

The very idea that nutrition is bad for you but Big Pharma’s chemicals are good for you is insane to begin with. But that’s what they want you to believe: Nutrition isn’t required in the human body, they claim. But pharmaceutical chemicals are essential!

What they want you to do is shut up, eat your (processed) food, take your (chemical) medications, get your (fraudulent) disease screening, pay your taxes, watch television ads, make more (sheeple) babies and stop questioning the status quo. And multivitamins? Stop wasting your money on them. You’ll need that money to buy more monopoly-priced pharmaceuticals, after all.

The stupid, it burns with the heat of a billion flaming supplements!

In actuality, it is Mike Adams and his minions who want you to shut up, eat your (organic) food, take your (chemical) supplements, get your (fraudulent) quack “screenings,” pay big bucks for your woo, watch infomercials about woo, make more babies, and stop questioning the status quo, which in woo-land is that “supplements = nutrition.” You won’t have any money left after paying all that money for those expensive supplements that aren’t any better than the vitamins made by the evil big pharma.

The bottom line is that there is science-based vitamin supplementation, and there is woo. Studies like some of the vitamin D studies, the study examining vitamin E and selenium, and this WHI study. From these studies, we can craft science- and evidence-based guidelines for when and in what people supplementation has benefits, with a full understanding that, like any other intervention, there may also be risks, which such studies can quantify. Woo constitutes magical thinking of the kind exhibited by Mike Adams in which supplements are a magic bullet that will prevent virtually all chronic diseases, “synthetic” vitamins are the work of Satan, and big pharma is suppressing the “truth.”

I’ll go with science-based supplementation, for all its shortcomings.

REFERENCE:

Marian L. Neuhouser, Sylvia Wassertheil-Smoller, Cynthia Thomson, Aaron Aragaki, Garnet L. Anderson, JoAnn E. Manson, Ruth E. Patterson, Thomas E. Rohan, Linda van Horn, James M. Shikany, Asha Thomas, Andrea LaCroix, Ross L. Prentice (2009). Multivitamin Use and Risk of Cancer and Cardiovascular Disease in the Women’s Health Initiative Cohorts Arch Intern Med, 169 (3), 294-304