NOHA NEWS readers may have noticed recent newspaper articles about a new Dutch study¹ showing that margarine is not the heart-disease preventative that it was widely thought to be. One such article, however, had the subhead "It’s better than butter, but it puts heart at risk." Is it really better?

For years in NOHA NEWS we have pointed out the deleterious effects of hydrogenated fats and have advised avoiding margarine and all other hydrogenated foods, even those only partially hardened.² An important problem is that these foods contain not only saturated fats, but also "trans" fatty acids, whose molecules have an unnatural geometric form seldom found in nature. (Frying foods can also produce some trans fatty acids.) Since their molecules lose the kinks found in natural, unsaturated, liquid fatty acids, trans fatty acids such as those found in margarine, produced by partial hydrogenation, result in a more solid and thus exceedingly convenient product with much the same consistency as saturated fat. Manufacturers favor this quality.

Margarine contains oils that have been partially hydrogenated to make the product harder, thus creating trans fatty acids. Though the [Dutch] study did not use butter per se, but other saturated fats, it clearly suggests that trans-containing margarines are worse than saturated fats from butter.

Much research has shown that increasing saturated fat in our diet can increase serum cholesterol and the chances of developing arteriosclerosis and heart disease. We are told to reduce our intake of saturated fats from butter and meat. In NOHA NEWS we have pointed out that extra saturated is not needed for energy storage in a sedentary population. Meats sold in our stores is "tender," coming, as it does, from domesticated animals that are essentially obese and loaded with saturated fat. In contrast, wild game, while tougher to eat, has far less saturated fat:

Typically, wild African mammals have a total body fat content of about 4 percent. In contrast, domestic animals . . . often have body fat levels approaching 25 to 30 percent. In addition, the fat of wild animals contains a relatively high proportion of polyunsaturated fat, commonly about five times as much polyunsaturated fat in proportion to saturated fat as domestic food animals.³

What about the trans fatty acids found in so many processed foods? The Dutch study (published in The New England Journal of Medicine and picked up by the popular press) carefully compares the effects in humans of unsaturated, trans, and saturated fatty acids on serum cholesterol and on the ratios between high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol. These ratios are critical factors in predicting arteriosclerosis and heart disease:

The Framingham Study demonstrated a significant relationship between elevated levels of total serum cholesterol and increased risk of coronary artery disease (CAD). Further studies of the lipoproteins responsible for cholesterol transport in the serum revealed that low-density lipoprotein (LDL) was positively correlated with increased risk of CAD, while high-density lipoprotein (HDL) was negatively correlated . . . the lipoproteins have been found to be a more powerful predictor of CAD than total serum cholesterol alone.⁴

Fifty-nine women and men completed the nine-week study. Food intake was controlled. Each three-week period differed only in that ten percent of total energy was provided by different fatty acids: (1) oleic acid, a monounsaturated fatty acid found in oils such as olive and sunflower, (2) trans isomers of oleic acid in which the fatty acid is still monounsaturated but has lost its natural kinks, or (3) saturated fatty acids such as those in palm oil and palm-kernel oil. The sequence of diets was assigned randomly to the participants and "the technicians who performed the chemical analyses were unaware of the subjects’ diet sequence. . . . The changes in fatty-acid composition of the erythrocyte [blood cell] membranes during these three dietary periods confirmed the subjects’ adherence to the diets."

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For the important ratios, LDL-to-HDL and total-cholesterol-to-HDL, both the trans- and the saturated-fatty-acid diets gave results significantly worse than for the oleic acid diet. However, for both ratios the trans-fatty-acid diet was significantly worse than the saturated-fatty-acid diet.

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Results were similar for both men and women on all three diets. Total cholesterol rose significantly in persons on both the saturated and the trans-fatty acid diets and, as expected, it rose more on the saturated fat diet. However, high-density lipoprotein (HDL), the "good" cholesterol, fell significantly in those on the trans-fatty-acid diet. HDL remained the same in those on both the other diets. LDL, "the atherogenic lipoprotein," rose significantly in those on the saturated and on the trans-fatty-acid diets.

For the important ratios, LDL-to-HDL and total-cholesterol-to-HDL, both the trans- and the saturated-fatty-acid diets gave results significantly worse than for the oleic acid diet. However, for both ratios the trans-fatty-acid diet was significantly worse than the saturated-fatty-acid diet.

What do these findings suggest for the margarine vs. butter controversy? Margarine contains oils that have been partially hydrogenated to make the product harder, thus creating trans fatty acids. Though the new study did not use butter per se, but other saturated fats, it clearly suggests that trans-containing margarines are worse than saturated fats from butter.

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¹Mensink, Ronald P. and Martijn B. Katan, "Effects of Dietary Trans Fatty Acids on High-Density and Low-Density Lipoprotein Cholesterol Levels in Healthy Subjects," The New England Journal of Medicine, 323(7):439-45, August 16, 1990.

²"The Fish and Game Diet," NOHA NEWS, Fall 1986; "Structural Versus Storage Fats," NOHA NEWS, Winter 1987; "Fish Oils and Vision," NOHA NEWS, Fall 1987; "Structural Fats Revisited," NOHA NEWS, Fall 1988; "Margarine or Butter?" NOHA NEWS, Fall 1988.

³Cohen, Mark Nathan, Health and the Rise of Civilization, New Haven and London: Yale University Press, 1989, pp. 73-74.

⁴Bernard, R. James, et al., "Effects of a Short-Term Diet and Exercise Program on Serum Apoproteins," Journal of Applied Nutrition, 401(1):5, 1988.