WASHINGTON (AP) - A national ad campaign this summer seems to claim the last word on eggs and cholesterol: "More studies say eggs are OK," it declares, over a picture of a pepper-and-mushroom omelette.
The advertisement continues: "The conclusion: If you're healthy, go right ahead and enjoy your eggs. Your cholesterol will probably stay about the same."
Nutritionists caution, however, that people with cholesterol problems - and certainly people with heart disease - should still be careful about how many eggs they eat.
Sweeping generalizations are unwise, because cholesterol in the diet affects people of all ages and health statuses differently, cautions Wahida Karmally, director of nutrition at Columbia University's Irving Center for Clinical Research.
"Some people's blood cholesterol will go up, and some people's won't go up," Karmally said. "It is definitely less potent in raising blood cholesterol than saturated fat. But we cannot just bypass cholesterol altogether, because it does have an impact on some people."
Adds Bonnie Liebman of the consumer group Center for Science in the Public Interest, who's critical of the industry ads: "Less impact does not mean trivial impact."
Since the mid-1960s, when studies first detailed the damage that cholesterol can do to arteries, the egg has been the most familiar symbol of the substance.
It has suffered accordingly.
The average person ate 320 eggs a year in 1967; today that's down to roughly 237 a year. The American Heart Association recommends that people limit consumption to four egg yolks a week, and says some people at risk of heart disease shouldn't eat them at all.
Take Leon Rothenberg, a 78-year-old retiree who lives in Chevy Chase, Md. He's heard of the new research but said he's sticking to his doctor's recommendation that he eat no more than two eggs a week.
The ad campaign, which has run widely on television and in print, is based on a University of Arizona analysis of 224 studies conducted since 1966 involving more than 8,000 people.
The analysis found that for most people, high-cholesterol foods such as eggs have less impact on dangerous cholesterol in the bloodstream than foods high in saturated fats.
Other studies have reported similar results, but none involved so many people over so long a time.
"It dispels long-held myths about what foods will and won't increase their risk for coronary heart disease," said Wanda Howell, the University of Arizona nutrition professor who published the study this year.
In scientific terms, the study concluded that one egg with 215 milligrams of cholesterol will increase cholesterol in the blood by about 4.5 milligrams per deciliter of blood.
Because the average American, each day, eats about 205 milligrams of cholesterol per deciliter of blood, eating an egg would increase that level by about 2 percent.
"It is basically unmeasurable," said Donald McNamara, executive director of the industry's Egg Nutrition Center.
Some critics allege that McNamara has a conflict of interest in promoting the study because he helped put it together.
McNamara, a colleague of Howell's at the University of Arizona, is listed as co-author. He left to take the Egg Nutrition Center job in April 1995, after the study was completed but not yet published.
In addition, the Egg Board provided $36,000 for the study, about 40 percent of its total money.
In answer to such criticisms, McNamara noted the findings are consistent with other studies and that most of the work examined by the analysis was not financed by the egg industry.
"We went through a rigorous review," he said.
But the ad campaign still makes some claims that trouble other nutrition experts, as do letters McNamara has circulated to hundreds of doctors contending the study "raises important questions regarding the appropriateness of an across-the-board ceiling on cholesterol for the entire population."
The ad campaign was approved by the Agriculture Department, which also publishes guidelines recommending that people try to control cholesterol in the diet. The agency says the ads were reviewed before release by a panel of scientists and by the Food and Drug Administration.
Olivia Tulay, who came to Takoma Park, Md., from Liberia six years ago, said eggs are a dietary staple in her homeland, but she restricted egg consumption after reading about cholesterol in this country. After seeing the new ads, she's begun eating more eggs.
"It has just come back to what I knew before: that eggs are good for you," Ms. Tulay said.