Writing in Slate last week, freelance reporter Christie Aschwanden wonders why athletes continue to take dietary supplements.

For, as she rightly points out, supplements are “expensive, they don’t improve performance, and they might make you test positive for dope.”

A case in point, says Aschwanden, is American swimmer Jessica Hardy, who was suspended for a year (and thus missed the 2008 Beijing Olympics) after she tested positive for clenbuterol, a drug used in asthma medication to increase airflow to the lungs. It also stimulates muscle growth.

Hardy claims she didn’t know clenbuteral was in the nutritional supplement she was taking at the time, Arginine Extreme. “For once," writes Aschwanden, “this doesn’t appear to be an outright fib.” Not only was clenbuteral not listed on the supplement’s label, but its manufacturer, AdvocCare, apparently didn’t mention it to Hardy, either — despite the fact that Hardy was being sponsored by the company.

AdvoCare, in fact, disputes the evidence provided by Hardy’s attorneys that Arginine Extreme contains clenbuteral. But, as Aschwanden points out, tainted supplements are nothing new, for supplement manufacturers have a long history of not being upfront about what goes into their products:

Supplements are risky thanks in part to a piece of legislation passed in 1994 called the Dietary Supplements and Health Education Act. The DSHEA essentially deregulated dietary supplements, including vitamins, herbs, protein shake mixes, nutritional supplements, and other powders and pills that millions of people of all levels of athletic ability might take to improve their health. Most people assume that if a product is available on store shelves, it must be OK. But supplements are not required to be evaluated or proven safe or effective before they’re sold. New rules finalized in 2007 gave the FDA power to regulate the manufacturing and packaging of supplements, but the agency’s ability to police supplement companies remains limited by DSHEA. Its chief author and most powerful advocate is Sen. Orrin Hatch, whose home state of Utah is home to much of the U.S. supplement industry. Hatch, who attributes his good health to the supplements he takes each day, fought a recent amendment to increase the FDA's ability to regulate the industry.

FDA investigations have repeatedly found safety problems with supplements, including dangerous ingredients — everything from diet pills containing a drug previously pulled from the market due to safety concerns to body-building supplements packed with anabolic steroids. These are hardly isolated cases. A 2004 study found that 18 percent of nutritional supplements purchased in the United States contained undeclared anabolic androgenic steroids. The FDA has also warned consumers about supplements laced with dangerous levels of selenium and chromium. In 2009, college baseball player Jareem Gunter told a Senate hearing that he'd ended up in the hospital with liver failure after taking a body-building supplement, and late last year, the Army set up a probe to investigate whether body-building supplements containing dimethylamylamine, or DMAA, a stimulant that can narrow blood vessels and arteries, were involved in the deaths of two soldiers and liver and kidney damage in others.

Buying the hype

Which brings us back, says Aschwanden, to asking "Why on earth would athletes take supplements?"

Or anyone else, for that matter.

“There’s no reason to think athletes benefit from supplementing their diets with these things,” writes Aschwanden. “Elite athletes spend hours each day training and must consume thousands of calories. It’s hard to become nutrient-deficient when you’re eating that much. The American College of Sports Medicine’s position statement says, ‘vitamin and mineral supplements are not needed if adequate energy to maintain body weight is consumed from a variety of food.’”

Yet, adds Aschwanden, “there’s plenty of incentive [for athletes] to believe the [supplement industry’s] hype. Endorsement deals from supplement companies provide a major source of income for many teams, coaches, and athletes, and trainers or coaches sometimes get paid to peddle supplements to their athletes.”

And when we hear that top athletes are using supplements, the rest of us think we need them as well. But, as I’ve reported in Second Opinion many times before, studies have shown that not only are dietary supplements unnecessary for most individuals, they may actually increase the risk of illness and death. Last fall, for example, a University of Minnesota study that evaluated 19 years of data found that women who took supplements were more likely to die than those who did not take supplements. And earlier this year, a group of scientists warned that high doses of dietary supplements (vitamins, minerals, herbs, amino acids, and botanicals) may actually increase the risk of cancer.

Yet Americans continue to spend $25 billion each year on these products.

You can read Aschwanden’s article on the Slate website.