In response to harsh criticism in the past few years about the amount of saturated fat in the American diet, many food manufacturers reluctantly have switched from palm and coconut oils and lard to partially hydrogenated vegetable oils made from soybean and corn oils.
In a stunning example of revisionist nutrition, new data show these oils _ found in margarine, vegetable shortening and a host of products ranging from doughnuts and pies to cookies and crackers _ may cause heart disease.
This latest nutritional flipflop may boil the blood of Angst-ridden consumers, who in the face of conflicting advice want to throw up their hands and break out the butter. Wrong. The basic message remains the same: Eat less fat.
The suspect ingredients are produced when food manufacturers convert vegetable oils to margarine or shortenings that are solid or semisolid at room temperature.
This process creates trans-fatty acids. For years, studies about trans-fatty acids conflicted: Evidence showed they both raised and lowered cholesterol levels. But several studies in the past two years have pointed to the harmful effects of these fatty acids.
A study by Dutch scientists, reported in The New England Journal of Medicine in 1990 showed trans-fatty acids raise the harmful elements in cholesterol while lowering protective elements.
The Agriculture Department now confirms the Dutch study. While the Agriculture Department study conducted for an industry group has not yet been published, those who have seen it say it supports the earlier Dutch work.