ScienceSkepticism

Seeing through the Supplement Hype

Will evening primrose oil help with PMS symptoms? How about lavender for depression? If you have ADD/ADHD, should you take omega-3? Will vitamin C help prevent a cold or lessen the symptoms? Can you enhance your budding superpowers with a regular dose of fish oil? In general, do you need to take supplemental vitamins and minerals to be physically and mentally healthy and feel good?

And perhaps most important, how do you find out the truth for yourself about health claims like this without spending days wading through PubMed? Especially if you’re anything like me and find medical research to be as easy to decipher as a calculus word problem written in Latin. On Post-it notes. Out of order.

To start with, Information Is Beautiful has a really cool interactive chart (Snake Oil? Scientific evidence for popular health supplements) that illustrates which supplements have evidence to support which uses. The chart ranks the supplement for a particular use based on large, human, blind, placebo-controlled trials only. Resources like this are a great starting point. You can see, for example, that the answers to all the questions in my first paragraph are No (well, except the superpowers one, which requires further testing).

(Continued after the jump.)

You can even look at the studies themselves by clicking on the document that is the basis for the chart. If you are seriously considering taking something, don’t rely solely on what this chart tells you. Check out the evidence further, particularly to look for research that is not only blind, but double-blind. A blind trial (in which the participants don’t know, for example, whether they are taking the supplement or the placebo) is not as rigorous as a double-blind trial (in which neither the participant nor the researchers know this information).

Why is this important? All humans have bias, even scientists. No matter how hard they try not to let this affect their work, if they believe that a particular supplement has a particular effect (or doesn’t have that effect), they are more likely to view the study from that perspective, ignoring or discounting (even unintentionally) the results that don’t support their viewpoint and giving greater weight to those that do.

Also, a single study showing an effect is not conclusive. Only after independent researchers have repeatedly duplicated the study methodology and achieved the same results can you have any idea whether the effect is real. Actually, even then, with health studies, it’s very difficult to control all the variables that might affect a person’s health, and it’s possible that the effect being attributed to the supplement is actually related to some other factor the test group has in common (related to what they eat, their environment, their health history, etc.)

Bottom line: Most people do not require supplements. You get plenty of vitamins and minerals from the food you eat (and that’s always the best source). Even if you don’t eat enough of a particular vitamin according to the Recommended Daily Allowance, odds are, you don’t actually have a deficiency, which would have serious enough effects on you that you would already be seeing a doctor or even be in the hospital, not musing over whether to self-medicate with Flinstones chewables.

But don’t just take my word for it. Do your own homework, and always check with your doctor before taking anything, even over-the-counter vitamins. If something has an effect, it has potential side effects and interactions. Fat-soluble vitamins (A, D, E, and K), for example, can build up to toxic levels in the body. This is a good example of why more of a good thing is not necessarily a good thing.

And if you’re even considering homeopathy, you might want to check out this list of scientifically controlled double-blind studies that have conclusively demonstrated its efficacy. (Actually, even if you’re not. Check this out. It’s hilarious. And true. And also hilarious.)

Image credit: Carlos Porto / FreeDigitalPhotos.net

Tip o’ the childproof cap to Diana Hagan for the Snake Oil chart link.

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Melanie Mallon

Melanie Mallon

Melanie is a freelance editor and writer who just moved to a small town outside Minneapolis with her husband and two young kids. When not counting how often the words "pride," "liberty," and "freedom" are used in local business, road, and pet names, she spends her time wrangling commas, making colon jokes, and raising her two kids to be critical thinkers. She is the managing editor of Skepchick Events, a Grounded Parents admin, and a Skepchick contributor. You can find her on Twitter as @MelMall, on Facebook, and on Google+

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