Should you take a multivitamin?: A HealthCentral Explainer

SSuchy Editor December 04, 2012
  • (flickr, jypsygen)

    About one third of Americans take a daily multivitamin. The reasons vary. Some people want to supplement their already healthy diet. Pregnant women are often advised to take them, as are vegetarians.  Some people have chronic illnesses that require them.  But no matter the reason, most people take multivitamins as a quick way to supplement vitamins and minerals that they may not get from their daily diet. 

     

    According to a report from the University of California-Berkeley School of Public Health’s 2013 Wellness Report on Dietary Supplements, Americans spend about $28 billion per year on supplements, such as multivitamins and herbal supplements, and the industry continues to grow.

     

    What are supplements?

     

    A dietary supplement is a substance taken by mouth, most often in pill form.  It usually contains a concentrated dose of a vitamin, mineral, herb, amino acid, plant extract, or hormone. 

     

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    The main purpose of supplements, of course, is to fill in your diet with concentrated doses of a substance you need – usually essential vitamins or minerals – that for whatever reason, you’re not getting in your diet. 

     

    What do the studies say?

     

    As supplements have come into popular use, they’ve been subjected to scientific study, though perhaps not as systematically as they should be.  A growing body of research, and some recent studies in particular, seem to paint a mixed picture of the benefits of supplements, specifically multivitamins.

     

     In October 2012, the Journal of the American Medical Association (JAMA) found that the use of a daily multivitamin in men was associated with about an 8 percent reduction in cancer cases over 10 years. 

     

    A couple of weeks later, JAMA came out with another study that found that the use of a daily multivitamin in men has no impact on their cardiovascular health. 

     

    Both of these findings came from an analysis of one big study called the Physicians’ Health Study II.  This is a database of 14,641 male U.S. physicians, aged 50 or older.  The study has tracked the men throughout their lives, taking note of lifestyle habits, any diseases they may develop, and cause of death once it occurs.

     

    For this particular study on multivitamins, half of the men were given a daily multivitamin and the other half were given a placebo.  This is significant because most studies on multivitamins have been purely observational--meaning that the study participants are not asked to change anything about their lifestyle, and no control group is used to test the causality of a result.

     

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    These JAMA studies were large-scale, randomized, double blind and placebo-controlled, which allowed researchers to say with some certainty that the multivitamins were the cause of the results.  In this case, the results were a modest reduction in cancer, but no discernible difference in cardiovascular health.

     

    Conclusions, if there are any

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    What can we draw from research like this?  One answer is that there is still a great deal to learn about supplements and multivitamins.

     

    UC Berkeley’s 2013 Wellness Report on supplements makes it very clear that while many Americans take a daily supplement and assume that it is both safe and effective, regulations within the industry don’t align with that assumption.  

     

    Supplements are regulated by the Food and Drug Administration (FDA), but since the 1994 Dietary Supplement Health and Education Act (DSHEA), they are regulated as a food and not a drug.  This means that a supplement does not have to go through the same rigorous tests and trials required of over-the-counter and prescription drugs before they appear on pharmacy shelves that. 

     

    Supplement manufacturers only have to send the FDA a copy of the label they plan before their products are distributed to the public.  This regulation is in place to keep the manufacturers from making any unfounded health claims. But once the supplement is on the market, it has a kind of ‘innocent until proven guilty’ stature, meaning that it will be able to stay on the market unless someone can prove they were harmed by it.

     

    Regulated as a food

     

    Because they are regulated as food, supplements and multivitamins are subject to what are known as ‘good manufacturing practices” (GMP).  These regulations focus on the identity, purity, strength and composition of the supplements.

     

    They’re meant to ensure that the supplement will not harm you, but offer no guarantee that the desired effect of the supplement will actually happen. 

     

    Putting supplements in their place

     

    What sometimes happens is that people who take supplements become less vigilant about consuming as much of their daily nutrients from their diet as possible.  They tend to rely on the supplements.  

     

    It is important to remember that the best source of any nutrient is usually the natural one.  While they have their place, supplements should always be treated as supplemental to a diet, rather than the main source of nutrients.  This means, for example, that you’re better off eating more citrus fruits than taking a vitamin C tablet, or adding more spinach to your diet instead of popping an iron pill. 

     

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    So, do I need one?

     

    There are certain situations where supplements and multivitamins can be very helpful to the body.  For example, a person who suffers from Crohn’s disease has a hard time absorbing nutrients from food.  In this case, supplements are very helpful in ensuring that his or her body gets the nutrients it needs. 

     

    Women need more nutrients than they can eat while they are pregnant or breast feeding, and the human body slowly becomes less efficient in absorbing nutrients as it ages.  In these cases, a multivitamin or supplement can be very beneficial.

     

    Your doctor will always be the best resource in helping you decide if you need a supplement or daily multivitamin.

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    Sources:

     

    Swartzberg, John E, University of California Berkeley, Dietary Supplements (2013).

     

    JAMA and Archives Journals (2012, November 5). Daily multivitamin use among men does not reduce risk of major cardiovascular events, study suggests. Science Daily. Retrieved from: http://www.sciencedaily.com/releases/2012/11/121105130405.htm

     

    JAMA and Archives Journal (2012, October 17). Multivitamin use among middle-aged, older men results in modest reduction in cancer, study finds.  Science Daily. Retrieved from: http://www.sciencedaily.com/releases/2012/10/121017123914.htm

     

     

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