The director of the Federal Trade Commission's bureau of consumer protection yesterday said a controversial advertisement for Kellogg Co.'s All-Bran that links the cereal to the prevention of cancer "is the type of advertisement that we believe should be encouraged."

The advertisement, which began running a month ago, has drawn scrutiny from the Food and Drug Administration and criticism from some state regulators for seeming to imply that eating All-Bran will somehow prevent cancer. But the FTC official, Carol T. Crawford, said she believes that the ad carefully qualifies Kellogg's claims for the product by pointing out that a National Cancer Institute study has found that a high-fiber, low-fat diet can reduce an individual's risk of getting cancer, and All-Bran is a high-fiber cereal.

"Kellogg has sought to inform the many consumers who do not know such a recommendation exists, and I see no risk of deception in the ad they have chosen to convey this information," Crawford said in a speech to a meeting of the American Advertising Federation. "The answer would be more difficult if consumers interpreted the claim to be that All-Bran alone would lower the incidence of some kinds of cancer." Crawford's remarks represented her views on the subject; the FTC has not yet formally taken up the matter.

A spokesman for the FDA, which has begun a review of the Kellogg ad, yesterday offered no opposition to Crawford's remarks, although the agency had earlier indicated a great deal of concern over the ad. Yesterday, William Grigg, the FDA's chief spokesman, said, "A major concern of the agency has not been the ad itself."

Rather, Grigg said, the agency is worried that advertisers will take advantage of the precedent set by the Kellogg ad and base advertising claims on more tenuous evidence. "If you can cite the National Cancer Institute, you can also cite the guy down the street who did a study in his basement," Grigg said. "The two lines that have to be drawn are how far you can go in identifying a specific product with a claim and what constitutes a legitimate study."