Christopher Labos: Myths about vitamins are hard to dislodge

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Many people see vitamins as an inexpensive and safe way to prevent disease. But just as the Holy Roman Empire wasn’t holy, or Roman, or an empire, vitamins aren’t cheap or risk-free, and they don’t actually prevent disease. In fact, they can make things worse.

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Last week, the US Preventive Services Task Force released its recommendations about whether to take vitamins, minerals, and nutritional supplements to prevent cardiovascular disease and cancer. As he did in 2014 when he last reviewed the evidence, he explicitly recommends against taking beta-carotene or vitamin E, and says there isn’t enough evidence to support the use of other vitamins.

In short, vitamins do not work. In fact, beta-carotene increases the risk of cancer and vitamin E the risk of hemorrhagic strokes.

So why do people keep taking them?

Surprisingly, the negative vitamin studies don’t seem to make a dent in sales, which equate to billions of dollars worldwide. When asked, most people say that they take vitamins to improve their health, but paradoxically, when you look at the data from the National Health Survey and Nutrition Screening For starters, people who take vitamins are more likely to be in good health. They smoke less, exercise more and have lower rates of obesity. Also, when you poll people about their use of vitamins, you reveal surprisingly contradictory beliefs. Nearly 90 percent of people surveyed agree or strongly agree that vitamins can help people meet their nutritional requirements. But 80 percent of them also agree or strongly agree that vitamins should not be used as a substitute for an unhealthy diet, and 75 percent agree or strongly agree that vitamins are not intended to Cure diseases.

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When you dig into people’s perceptions, they simultaneously recognize that vitamins don’t cure disease and at the same time see them as health enhancers.

Some people have valid medical reasons for taking vitamins; vitamin deficiencies do occur. But vitamin deficiencies are extremely rare.

That leaves many people taking vitamins for reasons that are not medically justifiable. A poll of Italian students found that those taking supplements didn’t take them because they were worried they weren’t getting enough vitamin D, iron, or omega-3s. The most common reason given was to improve athletic performance, even though there are little evidence to support this idea.

This belief system is incredibly difficult to dislodge. the editorial accompanying the USPSTF recommendations explains why this may be the case. Fairly successful marketing continues to convince the public that vitamin supplements have value, when they largely do not. Vitamins are considered natural, and people who abhor “big pharma” and take medications happily take a vitamin supplement without knowing that prescription drugs and vitamins are often made by the same company. Furthermore, people often prefer to do “something” even when that something is contrary to their own interests. Statistically, a soccer goalkeeper best strategy is to stay in the center of the net during a penalty kick. And yet goalkeepers feel compelled to dive in one way or another because in that environment inaction is unacceptable. The term has a name: action bias. It’s what compels some of us to honk our car horns in traffic when we know it will have little effect.

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Humorous examples aside, the problem with our fascination with vitamins is that only a quarter of people who take vitamins would stop taking them if advised to do so by public health. While it’s understandable to want to take care of your health, there are better and cheaper things you can do. Quit smoking, exercise regularly, eat plenty of fruits and vegetables, avoid junk food, and you will dramatically reduce your risk of cancer and heart disease. Just take vitamins, and you will not.

Christopher Labos is a Montreal physician and co-host of the Body of Evidence podcast.