The US Federal Trade Commission and the Food and Drug Administration are taking action to stop advertisements that claim certain dietary supplements can treat cancer and other diseases. The moves are part of Operation Cure.All, a federal, state and international initiative to crack down on fraudulent marketers.

Last week the FTC filed a lawsuit against the makers and distributors of the liquid supplement Seasilver, charging the companies with making false health statements about the product. The companies marketed Seasilver as a treatment or cure for 650 diseases, including cancer, AIDS, diabetes and Lyme disease, according to the complaint. At the FDA’s request, US marshals last week seized 132,480 bottles of Seasilver worth nearly $5.3 million dollars from the manufacturer’s San Diego headquarters.

“FDA will take vigorous actions against firms that prey on consumers and patients by selling worthless dietary supplements as cures for serious and chronic diseases and conditions,” FDA Commissioner Mark McClellan, MD, PhD, said in a statement. “Using these ineffective products is worse than wasting money – it may cause irreparable harm by delaying or replacing approved treatments that can bring actual health benefits.”

The supplement is marketed with television and radio infomercials, Web sites, e-mails and brochures, the FTC said. A 32-ounce bottle costs $39.95.

The agencies are seeking a permanent injunction to prevent Seasilver’s manufacturers, marketers and distributors from making fraudulent health claims, and refunds for consumers who purchased the product.

The Seasilver Web site says the company has “substantially curtailed operations” while the suit is underway.

In a separate action, the FTC also filed a lawsuit accusing the developer and marketer of Coral Calcium Supreme of making “false and unsubstantiated claims” about the benefits of the product. Letters have also been sent to at least two dozen Web sites that sell all types of coral calcium, warning them to remove false health claims from their pages.

Coral Calcium Supreme is widely advertised in 30-minute cable television infomercials, the FTC said. According to the agency’s complaint, the programs and brochures sent with the product say that research in reputable medical journals like the Journal of the American Medical Association (JAMA) has shown that calcium can reverse cancer and treat other diseases like multiple sclerosis and high blood pressure.

Those claims aren’t accurate, the FTC says.

“These and other claims go far beyond existing scientific evidence regarding the recognized health benefits of calcium,” the agency said in a statement announcing the court action. In fact, the role of calcium in cancer prevention is not clear.

Some studies have found that calcium can lower the risk of colon cancer and colon polyps, the precursors to colon cancer, said Marji McCullough, PhD, a nutritional epidemiologist with the American Cancer Society.

But there have also been studies that did not find a lower risk of colon cancer with calcium, and other research has even suggested the nutrient can have a negative effect in some other types of cancer. “There are actually some observations that calcium may weakly increase the risk of prostate cancer, especially advanced prostate cancer,” McCullough said.

“Most physicians and nutritionists feel that an adequate calcium intake is healthy,” said Herman Kattlove MD, medical editor for the ACS, “but it doesn’t have to come from coral. Any calcium pill will work.”

A JAMA spokesman said the journal and the AMA do not endorse or approve any commercial products or services.

As in the Seasilver suit, the FTC is asking the court for a permanent injunction to stop advertisements from saying coral calcium can cure cancer or autoimmune diseases, among other claims, said Heather Hippsley, assistant director for the agency’s advertising practices division.

The agency also wants refunds for consumers who purchased the product. She estimated that millions of consumers have bought Coral Calcium Supreme, spending tens of millions of dollars. The supplement costs $19.95 for a 90-day supply, according to the FTC complaint.

The agency is not seeking to stop sales of Coral Calcium Supreme, Hippsley said, just the false health claims.

A statement on the Web site of Robert Barefoot, the maker of Coral Calcium Supreme, says its content is being reviewed for accuracy, and maintains that many scientists agree that coral calcium provides significant health benefits.