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- Alex Hutchinson (@sweatscience)
Just when I thought I’d extricated myself from the great “bike helmets and risk homeostasis” debate, along comes a study suggesting that taking multivitamin pills causes people to behave in less healthy ways for the rest of the day. Even worse, the title of the paper in Psychological Science (“Ironic Effects of Dietary Supplementation: Illusory Invulnerability Created by Taking Dietary Supplements Licenses Health-risk Behaviors”) is likely to start an even fiercer debate about the correct use of the word “irony.” (Maybe it’s just a pun, since some multivitamins contain iron.)
But seriously, folks… The researchers gave a bunch of volunteers a harmless placebo pill; half of them were told it was a placebo, while the other half were told it was a multivitamin. Then they did some experiments and found that those who thought they’d taken a multivitamin “expressed less desire to engage in exercise and more desire to engage in hedonic activities, preferred a buffet over an organic meal, and walked less to benefit their health than the control group.”
It would be silly to take this study as evidence that multivitamins are “bad.” Still, I can’t help feeling that it does point toward a trade-off that people may unconsciously make when they look for “exercise pills” and other shortcuts. Most of the athletes I know take multivitamins as a way of “covering their bases” in case their diet falls short — as, in the real world, it occasionally will. But are there times when it only falls short because they feel that it’s okay to cut corners because they’ve got the pills as back-up? That’s what this study suggests. Maybe it’s better to take away the safety net, so you have more motivation to stay on top of your diet.