It has been estimated that over half of all Americans take some kind of vitamin or supplement. For older Americans, that number climbs to 70 percent. It is, inarguably, a massive industry; A market research analysis predicted it will have a global worth of almost $300 billion by 2024.

Whatever deficiency you are looking to correct, the vitamin industry has you covered. There is an ever-growing list of vitamin-infused products (vitamin coffee, vitamin beer, vitamin vodka and even vitamin e-cigarettes) and novel ways in which to cram vitamins into our body (vitamin mists, vitamin nasal sprays, vitamin skin patches, vitamin injections, vitamin underwear and vitamin rectal infusions). There are supplements that promise to boost your energy, like Goop’s aptly named product “Why Am I So Effing Tired,” to help you sleep and to improve your skin — just name a few.

But why do so many people take so many different kinds of vitamins and supplements? A 2018 survey of university students found that consumption was driven by a desire to enhance performance, cognitive function and overall wellbeing (79 percent). Interestingly, very few took supplements for the purpose of addressing perceived dietary deficiencies (2.9 percent). Research has also found that people who take supplements are more likely to adopt other healthy habits. It seems that often, supplements are simply viewed as part of a healthy lifestyle.

In reality, there is very little evidence to support the consumption of vitamins and supplements.

Studies have also found that people who take supplements are confident in their beliefs about both efficacy and safety of these products. A 2015 industry survey, for instance, concluded that 84 percent of Americans expressed confidence in the overall safety, quality and effectiveness of supplements.

In reality, there is very little evidence to support the consumption of vitamins and supplements. Studies have consistently found, for example, that multivitamins provide no clear health benefit. There is little evidence to support the use of most supplements in the context of sports, even for high-performance athletes. A 2018 systematic review from Canada found that “conclusive evidence for the benefit of any supplement across all dietary backgrounds… was not demonstrated” and that, for some supplements, there were real risks that should be considered.

Vitamins also do not work as an insurance policy against a poor diet. As nicely summarized in an editorial in the Annals of Internal Medicine — aptly titled “Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements” — “most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.”

The bottom line: Unless you have a clinically identified deficiency, the available science tells us there is little reason to consume supplements, at least in the manner pushed by the supplement industry. Your physician may recommend a supplement — folic acid during pregnancy, for example — but the science isn’t on the side of our current embrace of the more-is-better ethos.

To make matters worse, the supplement industry has little regulatory oversight, meaning that consumers have reason to question the quality of the science-free products they are buying. One study found that almost 70 percent of supplements tested had some degree of substitution (i.e., the product didn’t contain what was on the label) and one third contained contaminants or filler. And this isn’t benign stuff. The lead author of the study noted "some of the contaminants we found to pose serious health risks to consumers."

How risky can supplements be? Very. We know that high doses of some vitamins — such as vitamin E and A — can be harmful, including increasing the risk of cancer. And supplements can also lead to more acute problems. A 2017 study, for example, noted that 20 percent of all cases of liver toxicity are caused by herbal and dietary supplements. Another study found that 23,000 emergency department visits a year are the result of adverse reactions to supplements.

This puts us in a truly bizarre situation. Despite evidence that, in general, there are no clear health benefits, people take supplements — products that are lightly regulated, potentially harmful and are frequently contaminated or mislabelled — because they believe they work, are safe and are part of a healthy lifestyle. How can there be such a massive disconnect between the scientific reality and public perception?

While the social forces that brought us to this odd, pill-popping place are undoubtedly complex — see, for example, Catherine Price’s terrific "Vitamania" — part of the problem is the degree to which media representations are absent critical analysis. Unchallenged claims of benefit are absolutely everywhere, often riffing on the idea that supplements are a natural way to promote health. (How or why taking a pill or getting an injection or a rectal infusion is “natural” has never been clear to me.)

Alternative practitioners, such as naturopaths and “holistic” nutritionists (whatever that is), push supplements precisely because they fit the general natural-is-good gestalt of their practice (and, of course, because they can charge for them). Is it a surprise that the vitamin industry has helped to fund the lobbying of governments by naturopaths’ for regulatory recognition and funding by Medicare?

And, of course, celebrities also help keep the supplement and vitamin craze alive. For example, many have vocally embraced the idea that we should get hooked up to an IV vitamin drip. Indeed, without endorsements by people like Rihanna, Madonna, Gwyneth Paltrow and Simon Cowell, it seems unlikely that this science-free and potentially harmful health trend would have taken off.

To be clear, I’m not saying vitamins and supplements are always useless. For some populations, they are clearly beneficial (e.g., pregnant women). And interesting research and public health debates continue on the value of things like vitamin D supplementation. My point is that the existing evidence simply does not support our current love affair with supplements.

Ignore the supplement noise. More is not always better. Get the nutrients you need from the food that you eat. So, in summary: Apple, yes. Rectal vitamin infusion, no.

Timothy Caulfield is a Canada Research Chair in Health Law and Policy at the University of Alberta and host of “A User’s Guide to Cheating Death” (soon on Netflix).