|BUTTER OR MARGARINE?
Which fats are good, and which ones are bad?
December 25, 1997
in this forum:
How do I navigate the contradictory information about carbohydrates and olive oil ? Are organic foods worth extra calories? How do you judge whether a dietary product is real or fake ? How much fat should we eat everyday ? Jonathan Raff of Milwaukee, WI asks: In your study, Dr. Willett, you found trans fat to be the worst kind of fat on an ounce for ounce basis. One of the higher profile foods where trans fat is found is stick margarine. Is trans fat found in newer kinds of margarine (i.e. tub margarine) as well? Also, to what degree is trans fat worse than saturated fat?
Dr. Walter Willett responds:In carefully controlled feeding studies, trans fats have had about twice the adverse effects of saturated fats on the ratio of total serum cholesterol to HDL cholesterol, which is the blood cholesterol index that most strongly predicts risk of heart disease. In our study we found trans fats to be about three times as bad as saturated fats on an ounce-for-ounce basis in relation to risk of heart disease. The additional adverse effects of trans fats may be due to the fact they raise triglycerides compared to other types of fats and have other adverse metabolic effects that appear to be unique.
One piece of good news is that European margarine manufacturers have created margarines that no longer contain trans fats and are also low in saturated fats; some of these are now available in the United States. Thus, it is worth a careful look at the label to see whether the product is free of trans fat. One of the brands puts this information in bold type just above the official nutrition label. These new trans free margarines come in stick or tub form, so this distinction is no longer very useful in deciding which is a trans fat free product.
However, it is true that until recently the stick margarines generally contained more trans fats than the tub margarines.