WASHINGTON - The nation's top nutrition advisory panel has decided to drop its caution about eating cholesterol-laden food, a move that could undo almost 40 years of government warnings about its consumption.
The group's finding that cholesterol in the diet need no longer be considered a "nutrient of concern" stands in contrast to the committee's findings five years ago, the last time it convened. During those proceedings, as in previous years, the panel deemed the issue of "excess dietary cholesterol" a public health concern.
The new view on cholesterol in the diet does not reverse warnings about high levels of "bad" cholesterol in the blood, which have been linked to heart disease. Moreover, some experts warned that people with particular health problems, such as diabetes, should continue to avoid diets high in cholesterol.
But the finding, which may offer a measure of relief to breakfast diners who prefer eggs, follows an evolution of thinking among many nutritionists who now believe that for a healthy adult, cholesterol intake might not significantly affect the level of cholesterol in the blood or increase the risk of heart disease. The greater danger, according to this line of thought, lies in foods heavy with trans fats and saturated fats.
The panel laid out the cholesterol decision in December, at its last meeting before it writes a report that will serve as the basis for the next version of the Dietary Guidelines, a federal publication that has broad effects on the American diet. A video of the meeting was later posted online and a person with direct knowledge of the proceedings said the cholesterol finding would make it to the group's final report, which is due within weeks.
After Marian Neuhouser, chair of the relevant subcommittee, announced the decision to the panel at the December meeting, one panelist appeared to bridle.
"So we're not making a [cholesterol] recommendation?" panel member Miriam Nelson, a Tufts University professor, said at the meeting as if trying to absorb the thought. "OK. . . . Bummer."
Members of the panel, called the Dietary Guidelines Advisory Committee, said they would not comment until the publication of their report.
The Dietary Guidelines, which are due later this year from the Department of Health and Human Services and the Department of Agriculture, help determine the content of school lunches, affect how food manufacturers advertise their wares, and often serve as the foundation for reams of diet advice. Some foods that are high in cholesterol, such as liver, lobster, and shrimp, may find more takers with the new guidelines.
Walter Willett, chair of the nutrition department at the Harvard School of Public Health, called the turnaround on cholesterol a "reasonable move."
"There's been a shift of thinking," he said.
But the change also shows how the complexity of nutrition science and the lack of definitive research can contribute to confusion for Americans who, while seeking guidance on what to eat, often find themselves afloat in conflicting advice.
Cholesterol has been a fixture in dietary warnings in the United States at least since 1961, when it appeared in guidelines developed by the American Heart Association. Later adopted by the federal government, such warnings helped shift eating habits - per capita egg consumption dropped about 30 percent - and harmed egg farmers.
Yet even today, after more than a century of scientific inquiry, scientists are divided.
Some nutritionists said lifting the cholesterol warning was long overdue, noting that the United States was out-of-step with other countries, where diet guidelines do not single out cholesterol. Others support maintaining a warning.
The forthcoming version of the nation's Dietary Guidelines - the document is revised every five years - is expected to navigate myriad similar controversies. Among them: salt, red meat, sugar, saturated fats, and the latest darling of food-makers, Omega-3s. As with cholesterol, the dietary panel's advice on these issues will be used by the federal bureaucrats to draft the new guidelines.
The publication offers Americans clear instructions - and sometimes very specific, down-to-the-milligram prescriptions. But such precision can mask sometimes tumultuous debates that surround these issues.
"Almost every single nutrient imaginable has peer-reviewed publications associating it with almost any outcome," John P.A. Ioannidis, a professor of medicine and statistics at Stanford and one of the harshest critics of nutritional science, has written. "In this literature of epidemic proportions, how many results are correct?"
Now comes the shift on cholesterol.
Even as contrary evidence has emerged over the years, the campaign against dietary cholesterol has continued. In 1994, food-makers were required to report cholesterol values on the nutrition label. In 2010, with the publication of the most recent Dietary Guidelines, the experts again focused on the problem of "excess dietary cholesterol."
Yet many have viewed the evidence against cholesterol as weak, at best. As late as 2013, a task force arranged by the American College of Cardiology and the American Heart Association looked at the dietary cholesterol studies. The group found that there was "insufficient evidence" to make a recommendation.
"Looking back at the literature, we just couldn't see the kind of science that would support dietary restrictions," said Robert Eckel, the cochair of the task force and a medical professor at the University of Colorado.
The current U.S. guidelines call for restricting cholesterol intake to 300 milligrams daily. American adult men on average ingest about 340 milligrams of cholesterol a day, according to federal figures. That recommended figure of 300 milligrams, Eckel said, is "just one of those things that gets carried forward and carried forward even though the evidence is minimal."
Other major studies have indicated that eating an egg a day does not raise a healthy person's risk of heart disease, though diabetic patients may be at more risk.