An article being published today raises the possibility that margarine and other processed foods could be the cause of 30,000 of the nation's heart disease deaths.
The fact that margarine may be a major factor in heart problems is not new. A year ago, researchers at the Harvard School of Public Health announced findings that margarine can increase the risk for heart disease in women by as much as 70%. But the numbers in today's American Journal of Public Health article were seen as alarming and came under immediate attack.
The article was written by Harvard nutritionist Walter Willett, renowned worldwide as one of the leading researchers on diet and health disease.
"Will people be shocked? I suspect so," Willett told the Associated Press. "Many people who are trying to make good nutritional decisions for themselves and their kids are being grossly misled."
But others in the food industry were critical of the report, saying it was, in fact, an editorial and contained no new scientific data.
"This information has been worked on for quite a while," said Susan Borra, a registered dietitian with the International Food Information Council. "There's nothing new there."
The article, done at the request of the journal, is labeled as "commentary." In it, Willett posed the danger of what scientists have come to call "trans fats" which are produced during the hydrogenation process. That process is used to make such items as margarine, shortening, cookies, crackers and chips.
Doctors have long advised their patients to avoid saturated fat, found in both meat and butter. Instead, they have recommended polyunsaturated vegetable oil, for which there is no known risk of heart disease.
Manufacturers, in turn, have used hydrogenation to solidify the polyunsaturated oils, making them easier to use in various products. Hydrogenation, in turn, produces the trans fats.
While many foods are marketed as healthy because they contain no polyunsaturates, they do contain the trans fats that tend to increase so-called bad cholesterol, whose technical name is low-density lipoprotein. It has also been shown to decrease "good cholesterol," or high-density lipoprotein.
Willett said a number of foods carry "egregiously deceptive" labels such as "fat free" and "cholesterol free" and "cooked in vegetable oil" when in fact they contained harmful trans fats. He recommended that there be warning labels on food containing trans fats.
"Such warning labels are, indeed, more justifiable than those on cigarettes and alcoholic beverages because the nature of the product is invisible to the consumer," Willett said.
Ed Scarbrough of the Food and Drug Administration, said the agency is considering the labeling issue.
"The story about trans fat is still emerging," he said.
In his article, Willett said he determined that the median U.S. intake of trans fats is 2% of the daily number of calories consumed. He used that figure to calculate the number of people who would be subject to heart disease because of trans fats.
"Although the percentage of coronary heart disease deaths in the United States attributable to intake of trans fatty acids is uncertain, even the lower estimates . . . would suggest that more than 30,000 deaths per year may be due to the intake of partially hydrogenated vegetable fat," the article said. "Furthermore, the number of attributable cases of nonfatal coronary heart disease will be even larger."
Willett also said that, like the tobacco industry, the oil-processing industry claims the cause-effect relationship cannot be established without a randomized trial. He called such a trial "ethically and logistically impossible."
"Indeed, in this country, further epidemiological studies will be difficult because the food sources of trans fatty acids have changed so dramatically over the last several years, such that even persons with stable diets will not have had stable trans fatty acid intakes," Willett wrote.
Meanwhile, industry dietitian Borra said the article has an alarming sound, while problems could be avoided altogether by sticking to a diet in which the total fat intake is only 30% of the daily diet. According to health experts, the average fat intake is 46% of the average American's diet.
She also said she believes the article should have undergone peer review before it was published. Journal editor Mervyn Susser told the AP that the article did undergo internal peer review.
"It's respectable scientific opinion," he said.