By Ransdell Pierson and Anna Yukhananov

NEW YORK/WASHINGTON (Reuters) - Pfizer Inc, bowing to allegations of deceptive advertising lodged by a consumer watchdog group, has agreed to drop "breast health" and "colon health" claims from the labels of its widely used Centrum multivitamin supplements.

Although Pfizer said it disagreed with complaints lodged by the nonprofit Center for Science in the Public Interest (CSPI), it agreed to remove the claims from some Centrum product labels over the next six months and to withdraw them from websites and advertising within 30 days.

Watchdog groups such as CSPI have taken the lead in recent years in policing the accuracy of supplements' health claims amid widespread criticism that the U.S. Food and Drug Administration is not doing enough to help consumers navigate conflicting information. The Government Accountability Office has also said the FDA needs more power to regulate supplements.

The center sent a lengthy letter to Pfizer Chief Executive Ian Read in April alleging that separate Centrum products carried deceptive claims on their labels - that they support "energy and immunity," "heart health", "eye health," "breast health, "bone health" and "colon health."

The group threatened to sue Pfizer, which acquired the Centrum franchise through its purchase of rival U.S. drugmaker Wyeth three years ago, unless the claims were stripped from labels of the products.

Pfizer agreed to remove the claims related to breast health and colon health, and to modify language relating to heart health and energy.

"The company disagrees with CSPI's concerns, but has agreed to make these changes in order to fully resolve the issues raised by the organization," Pfizer said in a statement provided on Thursday.

A company spokesman declined to elaborate when asked about the scientific basis for the various health claims.

Labels for Centrum Ultra Women's and Centrum Silver Women's multivitamin supplements stated that those products supported "breast health." Likewise, labels for Centrum Ultra Men's and Centrum Silver Ultra Men's supplements claimed to support colon health.

"Those claims of breast and colon health implied that the supplements would prevent breast and colon cancer - disease prevention claims that supplement manufacturers can't legally make," the watchdog group said in a release.

The group said Pfizer partly based the breast and colon claims on the presence of vitamin D in the products, despite inconsistent or inconclusive evidence of vitamin D's protective role against breast and colon cancer.

Various other Centrum products will continue to claim they foster bone health and eye health, despite CSPI's earlier objections to the claims.

"A settlement is, by its nature, something where neither side gets all it wants," said Stephen Gardner, director of litigation for the center. "Once Pfizer agreed to drop the breast and colon cancer claims, we felt that that was too important to let things fall apart over eye and bone health."

Gardner said the vitamin claims might be interpreted as helping the structure of bone and eyes, a stronger argument than preventing complications.

For Centrum products claiming "heart health," labels and advertising will now note they are "not a replacement for cholesterol-lowering drugs." For products promoting "energy," language will be added to show they do not directly provide an energy boost, but instead support metabolic function, the consumer group said.

Many other companies continue to make unsubstantiated health claims for supplements, Gardner said.

"It's a tremendous problem. The supplement companies want consumers to buy their supplements instead of FDA-approved actual drugs. So they make claims of disease prevention."

(Editing by Andre Grenon)