For 15 million Americans, it is a daily ritual: gulping down a pill to reduce cholesterol.

They do it because their doctors tell them to. Their doctors, in turn, rely on recommendations from the National Institutes of Health and its scientists, such as Dr. H. Bryan Brewer Jr.

Brewer, as a leader at the NIH, was part of a team that gave the nation new cholesterol guidelines that were expected to prompt millions more people to take the daily pill. He also has written favorably of a specific brand of cholesterol medication, Crestor, which recently proved controversial.

What doctors were not told for years is this: While making recommendations in the name of the NIH, Brewer was working for the companies that sell the drugs. Government and company records show that from 2001 to 2003, he accepted about $114,000 in consulting fees from four companies making or developing cholesterol medications, including $31,000 from the maker of Crestor.

Brewer was far from alone in taking industry's money: At least 530 government scientists at the NIH, the nation's preeminent agency for medical research, have taken fees, stock or stock options from biomedical companies in the last five years, records show.

NIH Director Dr. Elias A. Zerhouni has told Congress that outside work should be allowed if "the scientist is giving advice in an area … that is not part of his official duties."

Information gathered by a congressional committee, in addition to company records and 15,000 pages of government documents obtained by the Los Angeles Times under the Freedom of Information Act, shows that NIH researchers have repeatedly crossed Zerhouni's line.

For example:

•  Dr. P. Trey Sunderland III, a senior psychiatric researcher, took $508,050 in fees and related income from Pfizer Inc. at the same time that he collaborated with Pfizer — in his government capacity — in studying patients with Alzheimer's disease. Without declaring his affiliation with the company, Sunderland endorsed the use of an Alzheimer's drug marketed by Pfizer during a nationally televised presentation at the NIH in 2003.

•  Dr. Lance A. Liotta, a laboratory director at the National Cancer Institute, was working in his official capacity with a company trying to develop an ovarian cancer test. He then took $70,000 as a consultant to the company's rival. Development of the cancer test stalled, prompting a complaint from the company. The NIH backed Liotta.

•  Dr. Harvey G. Klein, the NIH's top blood transfusion expert, accepted $240,200 in fees and 76,000 stock options over the last five years from companies developing blood-related products. During the same period, he wrote or spoke out about the usefulness of such products without publicly declaring his company ties.

Announcing such ties is not required by the NIH. The agency has encouraged outside consulting, and has allowed most of its scientists to file confidential income disclosure forms.

Supported by the taxpayers at a cost this year of $28 billion, the NIH oversees research with a mission to extend healthy life and to reduce "the burdens of illness and disability." The laboratories and offices of most NIH scientists are at the agency's woodsy, 300-acre headquarters in Bethesda, Md., nine miles north of the White House.

The scientists at the NIH — seen by many outsiders as neutral government experts — advise federal regulators and write hundreds of articles for influential medical journals. Some travel the world encouraging doctors to prescribe a particular medication.

The flow of drug industry fees and stock options to NIH scientists was disclosed in December 2003 in an article in The Times. The article also explained the bureaucratic means by which most of the payments had been kept secret from Congress, the public and the nation's doctors.

Subsequent inquiries this year by Congress have shown that even Zerhouni, the NIH's director, did not know the extent to which agency scientists were being paid by industry.

When leaders of the House Energy and Commerce Committee felt the NIH was not complying with a request to identify every drug industry payment, the panel went directly to 20 companies. Those responses revealed more than 130 consulting deals with industry that did not appear to have the required NIH approval. One of them was the $508,050 relationship between Sunderland, the Alzheimer's researcher, and Pfizer.

Other documents obtained this year by The Times, including programs of industry meetings for physicians that featured NIH scientists as speakers, reveal dozens more relationships not reported as approved by the agency.

The companies, in marketing their products, have frequently cited the NIH's reputation for high scientific standards. The cholesterol guidelines, for example, have been widely circulated by makers of anticholesterol drugs.