Short answers, pulled from the story.
A dietary supplement is a manufactured product intended to supplement a person's diet, sold as a pill, capsule, tablet, powder, or liquid. Its ingredients can include vitamins, minerals, fiber, fatty acids, and amino acids, and it may also contain plant pigments or polyphenols that are not nutrients.
In the United States, the supplement industry was estimated to be worth $151.9 billion in 2021. More than 95,000 dietary supplement products are marketed in the country, and about 60% of American adults take them, rising to 74% among people over the age of 60.
No, in the United States it is against federal regulations for supplement makers to claim their products prevent or treat any disease, since only a medication may legally make that claim. Companies may use Structure/Function wording such as helps maintain healthy joints, but the label must state that the FDA has not evaluated the claim.
The U.S. Food and Drug Administration regulates dietary supplements as a subset of food under good manufacturing practices established in 2007. No government approval is required before a supplement is made or sold, and the FDA can review a product for safety and effectiveness only after it reaches the market.
Testing has found widespread problems. From 2008 to 2011 the Government Accountability Office found 92% of tested herbal supplements contained lead and 80% contained other chemical contaminants, and a study of products sold between 2007 and 2016 identified 776 that contained unlisted pharmaceutical drugs. Fewer than half of those adulterated supplements were recalled.
There is little evidence of benefit when healthy people with a nutritionally adequate diet take dietary supplements. As of 2016, robust clinical data was lacking that any supplementation does more good than harm for healthy people, while strong data supports a plant-based diet of whole foods and daily exercise instead.