Correspondence

Trans Fatty Acids in Margarine

N Engl J Med 1995; 333:130-132July 13, 1995

Article

To the Editor:

In their letter ``Trans Fatty Acids in European Margarines'' (Feb. 23 issue),1 Michels and Sacks present a misleading perspective on the science of trans fatty acids and do not accurately describe today's margarine products. Although some epidemiologic research has suggested an association between trans fatty acids and coronary heart disease, other researchers have reviewed the same data and concluded that there is no basis on which to draw that conclusion.2,3 Recent reports have found no association between trans fatty acids and the risk of either myocardial infarction or sudden death from cardiac causes.4,5 In clinical trials, trans fatty acids replaced cholesterol-lowering fatty acids (oleic and linoleic acids), thus giving the appearance of raising levels of low-density lipoprotein cholesterol. Moreover, studies in animals and humans have also shown that the effect of trans fatty acids on blood lipids is neutral, much like that of stearic acid.6,7

Clearly, resolution of the independent biologic effects of trans and other fatty acids is complex, and the matter continues to be evaluated by the Food and Drug Administration and several health organizations. The lack of scientific consensus on the health effects of individual fatty acids is underscored by recent U.S. regulatory decisions to label saturated fatty acids solely on the basis of chemistry rather than on physiologic effects.

Public health policy in Europe differs from that in the United States. In Europe, emphasis has been placed on establishing certain fatty-acid profiles more than on reducing the amount of total fat, thus leading to the development of several full-fat margarines (with 11 g of fat per tablespoon) that have a high polyunsaturated-fat content. The table provided by Michels and Sacks reflects only the fatty-acid profile of the fat in these products and does not address the total fat content.

In the United States, public health policy strongly emphasizes the reduction of total fat and saturated fat in the diet to less than 30 percent and 10 percent of calories, respectively. As a result of the ongoing implementation of such policy and subsequent consumer demand, a variety of reduced-fat, lower-calorie margarine products are now available in this country from which consumers can choose. The average fat content of all margarine products sold today is about 60 percent (down 25 percent since 1980), with many products containing 40 percent fat or less. Table 1Table 1Caloric and Fat Composition of Various German, British, and American Margarines. shows the caloric and total fat content of a variety of margarine products available in the United States and compares them with the German and British products listed by Michels and Sacks.

Contrary to the statement by Michels and Sacks, a wide variety of margarine products are being produced and consumed in the United States and have strong consumer appeal. Thus, the content of total fat, saturated fat, and trans fatty acids has been minimized, providing consumers with products containing less fat and fewer calories than products used by European consumers.

Sue Taylor, M.S., R.D.
National Association of Margarine Manufacturers, Washington, DC 20005

7 References

1. 1

   Michels K, Sacks F. Trans fatty acids in European margarines. N Engl J Med 1995;332:541-542
   Full Text | Web of Science | Medline

2. 2

   Shapiro S. Trans fatty acid and coronary disease: the debate continues. 2. Confounding and selection bias in the data. Am J Public Health 1995;85:410-413
   CrossRef | Web of Science | Medline

3. 3

   Food and Nutrition Science Alliance (FANSA)Statement on trans fatty acids. Am Diet Assoc 1994;94:1097-1101
   CrossRef

4. 4

   Aro A, Kardinaal AFM, Salminen I, et al. Adipose tissue isomeric trans fatty acids and risk of myocardial infarction in nine countries: the EURAMIC study. Lancet 1995;345:273-278
   CrossRef | Web of Science | Medline

5. 5

   Roberts TL, Wood DA, Riemersma RA, Gallagher PJ, Lampe FL. Trans isomers of oleic and linoleic acids in adipose tissue and sudden cardiac death. Lancet 1995;345:278-282
   CrossRef | Web of Science | Medline

6. 6

   Nicolosi RJ, Dietschy JM. Dietary trans fatty acids and lipoprotein cholesterol. Am J Clin Nutr 1995;61:400-401
   Web of Science | Medline

7. 7

   Woollett LA, Daumerie CM, Dietschy JM. Trans-9-octadecenoic acid is biologically neutral and does not regulate the low density lipoprotein receptor as the cis isomer does in the hamster. J Lipid Res 1994;35:1661-1673
   Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: In the two prospective studies reported to date, trans-fatty-acid intake predicted the risk of coronary heart disease.1,2 In a number of retrospective studies of coronary heart disease, higher levels of trans fatty acids have been found among case patients than among controls. In the European Community Multicenter Study on Antioxidants, Myocardial Infarction, and Breast Cancer (EURAMIC),3 which Ms. Taylor refers to, the association between adipose-tissue trans fatty acids and myocardial infarction was diluted by the inclusion of two large centers in Spain where trans-fatty-acid levels and the risk of coronary heart disease are much lower than in other European countries. In these centers, it is impossible to study the effects of high trans-fatty-acid intake. When the authors excluded these statistically outlying data points, the odds ratio of 1.44 in the top category of trans-fatty-acid content was nearly identical to the value of 1.50 found in U.S. women.1 Thus, the EURAMIC study tends to support rather than refute an association of coronary heart disease with trans fatty acids.

The evidence is even stronger on the effects of trans fatty acids on lipoproteins, since it has been consistently demonstrated in well-controlled studies that trans fatty acids not only raise levels of low-density lipoprotein cholesterol but lower those of high-density lipoprotein cholesterol.4 In addition, trans fatty acids cause a mild increase in another atherogenic lipoprotein, lipoprotein(a). The effects may be slightly different in hamsters, as Ms. Taylor notes, but when data on humans and animals disagree, policy should be based on the findings in humans.

The low-fat spreads enumerated by Ms. Taylor are also available in Europe and Canada. However, information on the effect of the availability of low-fat products on the overall selection of food by consumers is surprisingly scant. Furthermore, it remains unclear whether replacing saturated fats with carbohydrates or with natural unhydrogenated oils is the healthier strategy. Monounsaturated oils tend to influence the balance between low-density lipoprotein and high-density lipoprotein more favorably than carbohydrates, since carbohydrates lower the level of high-density lipoprotein.5 The purpose of our letter was to point out that consumers in Europe have an additional choice in the form of regular margarines that are low in saturates, have virtually no trans fatty acids, and are high in essential fatty acids. In the United States, where labeling of trans-fatty-acid content is not required, consumers cannot select products on the basis of their trans-fatty-acid content. We encourage the National Association of Margarine Manufacturers to provide U.S. consumers with the same product options and with the labeling information that is needed to make an informed choice.

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

5 References

1. 1

   Willett WC, Stampfer MJ, Manson JE, et al. Intake of trans fatty acids and risk of coronary heart disease among women. Lancet 1993;341:581-585
   CrossRef | Web of Science | Medline

2. 2

   Gillman MW, Cupples LA, Gagnon D, Posner BM, Ellison C, Castelli WP. Margarine intake and subsequent coronary heart disease. Circulation 1995;91:925-925 abstract.
   Web of Science

3. 3

   Aro A, Kardinaal AFM, Salminen I, et al. Adipose tissue isomeric trans fatty acids and risk of myocardial infarction in nine countries: the EURAMIC study. Lancet 1995;345:273-278
   CrossRef | Web of Science | Medline

4. 4

   Mensink RP, Katan MB. Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. N Engl J Med 1990;323:439-445
   Full Text | Web of Science | Medline

5. 5

   Mensink RP, Katan MB. Effect of dietary fatty acids on serum lipids and lipoproteins: a meta-analysis of 27 trials. Arterioscler Thromb 1992;12:911-919
   CrossRef | Medline

Citing Articles (3)

Citing Articles

1. 1

   A. Aro, J. Van Amelsvoort, W. Becker, M.-A. van Erp-Baart, A. Kafatos, T. Leth, G. van Poppel. (1998) TransFatty Acids in Dietary Fats and Oils from 14 European Countries: The TRANSFAIR Study. Journal of Food Composition and Analysis 11:2, 137-149
   CrossRef

2. 2

   Erika von Mutius, Stephan K Weiland, Christian Fritzsch, Heinrich Duhme, Ulrich Keil. (1998) Increasing prevalence of hay fever and atopy among children in Leipzig, East Germany. The Lancet 351:9106, 862-866
   CrossRef

3. 3

   Byers, Tim, . (1997) Hardened Fats, Hardened Arteries?. New England Journal of Medicine 337:21, 1544-1545
   Full Text