Trans Fatty Acids in European Margarines

To the Editor:

The content of trans fatty acids in our foods has been causing concern because of reported adverse effects on serum lipid levels and coronary heart disease. Even a typical Western diet can have enough of these trans isomers to elevate the risk of coronary heart disease considerably. Unfortunately, consumers themselves have only limited control over their intake of trans fatty acids, since despite progress in food labeling, the new regulations do not require information on trans fatty acids to be displayed on food packages.

Margarine has been identified as one of the major sources of trans fatty acids. According to our analysis, the trans-fatty-acid content of margarines manufactured in the United States ranges widely from 0.1 to 0.9 g per teaspoon (5 ml, or 2 to 18 percent of total fatty acids). Although American consumers who prefer margarine to butter do not have the ability to choose a margarine that has minimal or no trans-isomer content, European consumers do. In England, Flora margarine is promoted as having no trans fatty acids; we analyzed this product and confirmed that the trans-isomer content is negligible. In Germany, products that are termed "diet" margarines (Diatmargarine) cannot contain partially hydrogenated fats or oils. To achieve the solid consistency of the diet margarines, manufacturers are permitted to blend the unmodified liquid oils with a small amount of "hardstock," which are naturally solid fats, or to hydrogenate 10 to 15 percent of the vegetable oil fully, thereby producing a fat richer in stearic acid, a saturated fatty acid that does not raise serum levels of low-density lipoprotein cholesterol. These products have a favorable composition of fatty acids: the trans-fatty-acid content is negligible, and the saturated-fatty-acid content is low The composition of diet margarines from the Netherlands is similar to that of the German ones.

In contrast, German products termed Reformhausmargarine (loosely translated as "natural" margarines) are prohibited from containing any oils that have been subjected to hydrogenation, partial or full. Unfortunately, the Reformhausmargarines derive their solid consistency from the addition of relatively large amounts of naturally hard palm-kernel oil, palm oil, and coconut oil, which enrich these not-so-healthy products with nearly 50 percent saturated fatty acids. These products are analogous to Land O' Lakes Country Morning Blend Light, a margarine recently introduced in the United States that is promoted as being free of trans fatty acids, in which butter is used to harden the product. Products such as Diatmargarine and Flora margarine demonstrate that a low amount of trans fatty acids need not be accompanied by an increase in saturated fatty acids that elevate serum cholesterol levels, as in the Reformhausmargarine or the American blend of butter and oil.

Margarines can be produced that appeal to the consumer and do not contain either trans fatty acids or high levels of saturated fatty acids. Although this has been done in Europe, American food manufacturers are still manipulating our foods in a way that current scientific research suggests may compromise health. Furthermore, the lack of information on trans fatty acids on food labels does not allow one to make an informed choice among available options.

Karin Michels, M.S., M.P.H.
Frank Sacks, M.D.
Harvard School of Public Health
Boston, MA 02115

References

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Willett WC, Stampfer MJ, Manson JE, et al. Intake of trans fatty acids and risk of coronary heart disease among women. - Lancet 1993;341:581-5.


Litin L, Sacks F. Trans-fatty-acid content of common foods. - N Engl J Med 1993;329:1969-70.


Bonanome A, Grundy SM. Effect of dietary stearic acid on plasma cholesterol and lipoprotein levels. - N Engl J Med 1988;318:1244-8.


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