(CN) – The U.S. Food and Drug Administration said Monday it is tightening regulations on companies that make nutritional supplements, especially those that make claims about curing or preventing Alzheimer’s disease.

The FDA posted 12 online warning letters and five advisory letters to companies in the United States and abroad that are illegally selling 58 products marketed as dietary supplements that claim to prevent, treat or cure Alzheimer’s.

“These products, which are often sold on websites and social media platforms, have not been reviewed by the FDA and are not proven safe and effective to treat the diseases and health conditions they claim to treat,” the FDA said in announcing the crackdown. “These products may be ineffective, unsafe and could prevent a person from seeking an appropriate diagnosis and treatment.”

FDA commissioner Scott Gottlieb, M.D. added: “Health fraud scams prey on vulnerable populations, waste money and often delay proper medical care – and we will continue to take action to protect patients and caregivers from misleading, unproven products.”

Gottlieb said the FDA’s actions address the “booming growth” of the dietary supplement industry, and the organization’s actions are an effort to enforce the Dietary Supplement Health and Education Act enacted by Congress 25 years ago.

The FDA said it reviewed the supplement companies’ websites and social media sites for false claims of products. Warning letters posted online involve TEK Naturals, John Gray’s Mars Venus, Nutrition Coalition, Blue Ridge Silver, Sovereign Laboratories, DK Vitamins, Peak Nootropics (aka Advanced Nootropics), Gold Crown Natural Products, Emmbros Overseas Lifestyle, Earth Turns, and Capris Associates Inc./BR Naturals.

The companies were asked to respond to the FDA within 15 days. “Failure to correct the violations promptly may result in legal action, including product seizure or injunction,” the FDA said.

Arizona-based Sovereign Laboratories markets a colostrum product derived from cows. According to the FDA, the company claims its products may “help reduce or prevent the symptoms of Alzheimer’s, along with the symptoms of Huntington’s disease, sporadic ALS, epilepsy, post-stroke neuro-degradation and other neurodegenerative disorders.”

Peter Lurie, president of the Center for Science in the Public Interest, applauded the FDA’s crackdown.

“No dietary supplement should be marketed as a prevention or a treatment of any disease, least of all Alzheimer’s disease, whose afflicted population would be especially vulnerable to illegal marketing,” Lurie said in a statement.

He noted the FDA took similar action against supplements marketed as treatments of opioid-addiction withdrawal in January 2018, after the Center for Science in the Public Interest filed a complaint with the FDA the previous month.

“It’s encouraging that Commissioner Gottlieb seems open to making changes to the Dietary Supplement Health and Education Act – the deeply flawed law that has long handcuffed the FDA’s regulatory efforts and has produced the sprawling, largely unregulated and often reckless industry we have today,” Lurie said.

The Center for Science in the Public Interest supports requiring the FDA to require supplement manufacturers to list their products with the FDA, Lurie said.

“With the supplement industry,” he said, “any innovation is clearly in the marketing realm and not in the scientific realm.”

This past fall, the FDA sent out warning letters to companies that are illegally marketing or selling e-cigarette products.