Vitamins and Faulty Studies


| 6 Comments
As someone who has taken a vitamin every morning for as long as I can remember, I never thought to question if anything bad could come out of it. I never thought to, that is, until I stumbled upon this article quoting a recent study in the Archives of Internal Medicine saying that "taking multivitamins and other supplements may actually shorten your life."

Naturally, further investigation was necessary, so I continued reading the article and found out more about the study. The amount of scientific problems that it faces makes it impossible to convince myself and many others of this finding, but I will let you make that decision for yourselves based on the information.

vitamin1.jpgInformation was collected from about 40,000 women several times over 22 years. Stop right there. This study claims that the findings apply to men as well, when they were not even part of it. Interesting. Okay, moving on. The information gathered was regarding health issues and vitamin/supplement use. Researchers then used this information and looked into health and death records and found seven supplements that showed a pattern in hastening death. Those supplements were:

1. Vitamin B6vitamin2.jpg
2. Folic Acid
3. Iron
4. Magnesium
5. Zinc
6. Copper
7. Multivitamin

According to this research study, mortality rate increased anywhere from 2.2% (multivitamin users) to 18% (copper users).

Normally, this finding would turn heads and make people extremely worried that something they thought they were doing to help their bodies was actually killing them faster. However, the article I found carefully pointed out the flaws in the study, and why this study is not one to take advice from.

1. The study was observational. Without an experimental design, there is no way that these findings can lead to causation. While there were control factors (age, diabetes, physical activity, high blood pressure, a few dietary habits), there was no placebo group, and therefore there could be confounding or third variables involved.

2. The study was limited to a group of older women. The average age was 62, which is clearly not representative of the population of people who take vitamins (babies take vitamins, I take vitamins, my parents take vitamins). Also, there has already been proof that iron increases risk of heart disease in post-menopausal women, so any finding regarding iron being dangerous has already been established, but does not apply to every age group. The probable reason that iron is included in the list of harmful supplements in the first place is because of the very restricted age group included in the study.

3. According to a study in Psychological Science, people who take vitamins generally use that as an excuse to "cheat" in their diets and make poorer health choices. Therefore, Psychological Science is simply condoning that the health choices people are making BECAUSE they take vitamins is what is leading them to a hastier death- NOT the vitamins themselves. The first study looks past this and has the Texas Sharp Shooter Problem of piecing together unrelated material just to make it look true.

4. It is inarguable that certain vitamins have extremely important benefits. According to the American Heart Association, three servings of omega 3-rich fish per week help prevent heart disease. This is an extremely hard goal to meet, so there are supplements that people take to help make this intake possible. Studies have shown that men with highest omega-3 levels (both from natural sources and supplements) have the lowest risk of dying of heart disease. The researches gave "2,800 heart-attack survivors 1 gram of fish oil per day [in Italy], and the supplement reduced the risk of dying of heart disease by 30% and of sudden cardiac death by 45% compared to those who did not supplement their diets."

So, we have seen several problems with the first study by breaking it down and looking past the one statistic they provided. It is important that with findings such as this, which could change the lifestyle of millions of people, we take the time to see if the finding was sincere and completely accurate.

Oddly enough, Chuck Norris blogged about this study and said, "it was based upon inadequate research, faulty statistics and no clinical verification or medical investigation". In his blog, he speaks about how in 2002, the Journal of the American Medical Association published a study that all adults should take a multivitamin to prevent chronic diseases. Dr. Jaakko Mursu, the leader of this new negative vitamin study has "confessed to Reuters that the three surveys don't prove vitamins and supplements are harmful -- just that they may not be so helpful as we assumed or they are marketed to be" This, however, is NOT a health revelation. We already knew this. So before publishing a huge result that vitamins are killing people, Mursu should have clarified that this finding is not a health scare.

What do you guys think? Would the study make you stop taking vitamins?


6 Comments

Your excellent post made me wonder two things.

First, what data would cause people to stop taking vitamins?

Second, how does this study - and indeed the excellent criticisms you make about it - differ from those three papers in 1950 that first argued that smoking causes cancer?

Honestly, nothing would make me stop taking vitamins unless there was 100% positive evidence that vitamins are bad for you. My blood work has always come back perfect (with the exception of anemia a few years ago which was remedied by iron supplements), so why compromise my current health just because of a few studies? There are negative effects of taking virtually any kind of supplements that are foreign to the human body, but if it has not yet gotten to the point where there is no doubt that it is life threatening, I have no intention of stopping, and I don't think other logical people would either.

With regards to the three papers, the vitamin study concluded that vitamins lead to earlier death while the papers about smoking said that while there is a statistical association, lung cancer may still be due to confounding variables and may not be the direct result of smoking. These papers were proving their case, but still left it open for other possible reasons, while the vitamin study made one conclusion and left the logical people to do the rest of the work in determining that this is in fact not the only possible cause.

You are making such good points, I thought I'd see what Mursu actually said in the scientific paper itself (the link may work only from within the PSU network).

It seems pretty carefully worded to me. From the abstract of the paper

"Although dietary supplements are commonly taken to prevent chronic disease, the long-term health consequences of many compounds are unknown.....

....In older women, several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk; this association is strongest with supplemental iron. In contrast to the findings of many studies, calcium is associated with decreased risk."

So no one is saying anything about causality, at least in the paper. In fact they are really cautious in the main text:

"It is not advisable to make a causal statement of excess risk based on these observational data; however, it is noteworthy that dietary supplements, unlike drugs, do not require rigorous RCT testing, and observational studies are often the best-available method for assessing the safety of long-term use. Based on existing evidence, we see little justification for the general and widespread use of dietary supplements. We recommend that they be used with strong medically based cause, such as symptomatic nutrient deficiency disease."

Seems like pretty sensible cautionary concerns being raised here, nothing more. So where did the hype come from? Media reporting of the story, or did the authors do an over hyped press release?

Lucky you on your good blood work.

Do you reckon it's good because you are young, have a good genome and live well, or because of your vitamins?

Wow, the actual paper was very eye opening. It could very well be that, like we learned in class today with Faye Flam, the media blew this out of proportion and just wanted to write an exciting story. The particular article that I found, which is linked on my original blog post, is not an actual article saying that vitamins are killing people faster. The article I found was one very much against this finding. It is very possible that this article was blowing the study out of proportion, but it did take a direct quote from the Archives of Internal Medicine saying "taking multivitamins and other supplements may actually shorten your life." Seeing what the actual report said, however, does make me question the initial article that I read. While it has extremely good arguments against why the study (that it portrayed) is not accurate, I wonder if in fact the media made something out of nothing.

With regards to my personal health, I have always been a dancer, so I get a lot of exercise, and none of my family members really get very sick. However, we all take vitamins. Like the initial post said, there can easily be confounding variables with results concerning vitamins. I could have great health because of my genes and my daily habits, because I take vitamins, or a mixture of both.

The study would NOT make me stop taking multivitamins. As you pointed out there were many flaws to this study. First was the chosen group of candidates for the study(of women close to their 70s). Not very representative of an enitre population, plus the large fact that the study used the Texas Sharp Shooter approach and only published what it wanted to without understanding both spectrums of the story.

I do beleive however about one point that you made in your post, that people assume that if they are supplementing a daily vitamnin into their diet that they are NOW allowed to upset their diet and exercsie program because the vitamins "make-up" for it.Even the best supplement is no substitute for good nutrition. In many Western countries, people tend to consume foods that are high in calories, but lack nutrients that are vital for good health. I believe that people need to asses that it may not be the vitamin that is causing poor health but other third variables, as you mentioned.

Heres an article that pertains to the group of elderly persons studied in your entry. It explains what types of supplementation are healthy for "them." (taking into consideration their diet and wellness needs,which is purely reprsentative of that population).

National Institute in Aging

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