The federal government yesterday made its most important move to date to control the health-food industry, charging that it misleadingly promotes food products as treatments for a wide variety of ailments.

The effort came in a novel, seven-count indictment by a federal grand jury in Buffalo against General Nutrition Inc., a major U.S. health-food chain, and its officers on charges of conspiring to defraud the Food and Drug Administration of its regulatory powers.

The indictment accused the firm and its officials of criminal violations of the law for attempting to "disguise" one of the company's popular products as a food supplement, while marketing it as a drug with therapeutic powers.

Salvatore R. Martoche, U.S. attorney for the Western District of New York, said the action represented a "strong new thrust" that "serves notice on the health-food industry that this kind of conduct will not be tolerated . . . . This case properly can be characterized as the most significant and far-reaching case to be brought by the FDA in recent years."

FDA spokesman Bruce Brown said the indictment was "an escalation of our regulatory activity in the health-food industry marketplace for the purpose of trying to eliminate the promotion of health foods for therapeutic purposes." He said the agency hoped that the threat of criminal sanctions might "bring under better control the entire health-food industry."

Yesterday's indictment focused specifically on a capsule, manufactured in England, of the oil of the evening primrose plant. Under the name Gammaprim, it is sold exclusively in this country by General Nutrition, which has over 1,000 U.S. outlets, including more than a dozen General Nutrition Centers in the Washington metropolitan area.

Based on undercover work by the FDA regional office in Buffalo, the government alleged that while Gammaprim was labeled as a food supplement, it was promoted, through publicity, booklets and oral representations by company sales personnel, as a treatment for maladies from high blood pressure to arthritis, multiple sclerosis, breast cancer, heart disease, alcoholism and asthma.

Martoche said the company's sales of Gammaprim are one example of ways health-food outlets are "avoiding compliance with FDA requirements that are designed to protect the American public." It is not a question of whether the product works, he said, but rather that it has not been proven to do so and may divert consumers with serious illnesses from known remedies.

Martoche said General Nutrition Inc. and its subsidiary corporations are the largest retail chain in the United States selling health-food products, and one of the largest in the world. It does business under the names General Nutrition Center and GNC.

Martoche said the case against the company, headquarters officials and officials at outlets in the Buffalo area represented an innovative combination of the Food, Drug and Cosmetic Act, which the FDA enforces, and general provisions of the U.S. criminal code that carry stiffer penalties. "It's the first time to our knowledge that a company has been charged with conspiring to defraud the FDA," he said.

FDA officials note that under the law, a food supplement that does not make medical claims can be sold without premarketing approval for safety and effectiveness. But advance studies generally must be submitted to FDA demonstrating that a drug is safe and effective for its therapeutic claims before it can be marketed.

The indictment cites extensive correspondence between company officials to get favorable publicity, "self-help" booklets provided at retail outlets and oral presentations to FDA investigators on the multiple healing powers of evening primrose oil. The goverment contends that the efforts represent a systematic, misleading promotional scheme.

Contacted at the firm's headquarters in Pittsburgh, corporate counsel George Basco said he had not seen the indictment, but "we don't believe either the company or any of the employes has done anything wrong. We certainly intend to vigorously defend ourselves against the charges."

He said Gammaprim is "sold as a food supplement . . . . We only refer to physiological aspects of a product and never therapeutic aspects of a product . . . . It's our position that we're selling a food and not a drug."

Under the indictment, the company, if found guilty, could face a maximum fine of $16,000, while its president and two of its vice presidents each could face maximum penalties of 11 years in prison and and a $16,000 fine.

The manager and assistant manager of two outlets in the Buffalo area face penalties of one or two years imprisonment and fines of $1,000 to $2,000.

FDA sources said the agency already had exhausted its normal range of regulatory actions, including warnings to the company dating back to 1981 about its promotion of evening primrose oil. The government earlier successfully challenged health-food companies' right to market so-called starch blockers, a controversial diet aid.

At a General Nutrition Center in the Fair Oaks Mall in Fairfax, Gammaprim was selling yesterday for $21.99 per bottle of 100 capsules. Label directions recommend up to six capsules a day as a food supplement. A clerk, who asked not to be identified, said he is not allowed by law to prescribe the product or recommend it to customers.