MARGARINE. Margarine was invented by Hippolyte Megè-Mouriès in 1869 in response to an order from Napoleon III to produce a cheap and stable substitute for butter. The product had a pearly luster, and Megè-Mouriès named it margarine after the Greek word meaning 'pearl-like'. The process of manufacture entailed churning oleo oil (obtained from beef tallow) at 77 to 86°F (25 to 30°C) with water or milk. The product was flavored with salt. Over time margarine has been used in baked goods, to improve the palatability and quality of butter, to improve heat transfer during frying, and to add to the flavor of foods. Margarines may contain about 80 percent fat (animal or vegetable), milk solids, emulsifying agents, and salt.
The U.S. Food and Drug Administration (FDA) established a standard of identity for margarine. It must contain not less than 80 percent edible fat of animal or vegetable origin; water, milk, or milk products; suitable edible protein, and vitamin A. Optional ingredients include vitamin D, salt or potassium chloride, nutritive carbohydrate sweeteners, emulsifiers, preservatives, colorants, flavorants, acidulants, and alkalizers. Fat-free and low-fat spreads are available commercially. While it is convenient to describe them as margarines, they do not conform to the FDA standard of identity. Early in the twentieth century the texture of margarine was improved by replacing animal fat with coconut oil. In the 1930s hydrogenated vegetable oils became available, and these became the basic ingredient of margarine. Hydrogenated vegetable fat provided a uniform base for margarine, and control of the extent of hydrogenation gave a series of fats of varying hardness that could be used for specific products.
The hydrogenation process causes migration of the double bonds of vegetable oils and provides both cis and trans double bonds, whereas the double bonds in most vegetable oils are in the cis configuration. A cis double bond is one in which the hydrogen atoms attached to the carbons that form the double bond are on the same side of the carbon chain, and the molecule "bends" at the site of the double bond. In trans double bonds the hydrogen atoms are on opposite sides of the carbon chain, and the molecule has a more linear configuration, similar to that of a saturated fatty acid. Trans double bonds are not unknown in nature, occurring in many plant fats and some animal fats. Where most of the vegetable fats contain eighteen carbon atoms or more, the trans animal fats are generally shorter than eighteen carbon atoms.
Concern regarding the biological effects of trans double bonds was voiced in the 1940s. Studies of effects of trans fats on growth and reproduction in rats show that they have no untoward effects when the diet is replete in essential fatty acids, but when fed as the sole source of fat, they exaggerate symptoms of essential fatty acid deficiency. In this they resemble saturated fatty acids, as they do in many other biological processes.
The effects of trans fats in experimental atherosclerosis were first examined in the 1950s by Gardner McMillan and his colleagues. They found that, while trans fats raised blood cholesterol levels in cholesterol-fed rabbits, their presence in the diet did not lead to more severe atherosclerosis. Studies of rabbits fed cholesterol-free diets, of pigs, and of vervet monkeys have yielded similar results. One six-year study of the effects of partially hydrogenated soybean oil yielded atherosclerosis at a level of severity seen in rabbits fed coconut oil and less than that seen in rabbits fed soybean oil.
In humans the effects of trans fats on cardiovascular disease can only be assessed by effects on risk factors. Early studies yielded variable results of trans fat–rich diets on serum cholesterol. It was observed that the level of hypercholesterolemia varied inversely with the amount of linoleic acid in the diet. Trans fat was not hypercholesterolemic in diets that were also rich in linoleic acid. No differences were found when tissue levels of trans fats in human subjects who had died of cardiovascular disease were compared with that in human controls.
Analysis of human studies in which energy from carbohydrates was replaced by trans–18:1 fat shows that this exchange leads to increases in levels of LDL cholesterol and decreases in levels of HDL cholesterol, which increases the risk of cardiovascular disease. Serum levels of lipoprotein(a), another risk factor, are also increased.
Epidemiological studies of the effects of dietary trans fat on coronary heart disease yield variable results. One study (239 cases and 282 controls) shows a positive association between high intake of trans fat and coronary heart disease (CHD) risk but an inverse association at moderate intake, whereas another study carried out in nine European countries (671 cases and 717 controls) found no association between intake of trans fat and CHD risk. Cohort studies found positive associations between intake and risk only at the highest level of intake. Two studies found the lowest risk at the third quintile of intake. The Seven Countries Study revealed a significant positive association between 18:1 trans fatty acid intake and twenty-five-year CHD mortality rates.
The overall findings concerning intake of trans fat and risk of CHD are not consistent. These disparities are complicated because the data regarding effects of specific trans fatty acids are sparse and differences between populations and interactions with other dietary ingredients are not considered. The trend to consider dietary patterns rather than individual dietary ingredients may help organize the findings. Nevertheless the sum of the experimental data suggests that high intake of fats containing trans fatty acids may pose an increased risk of CHD. The industry response to these findings has been a major effort to produce margarines that are either low in trans-unsaturated fat or devoid of it.
Much is unknown about the balance of dietary fats–trans fat, saturated fat, and polyunsaturated fat and their interactions with other components of the diet. The attitude should be one of prudence, not panic.
See also Baking; Butter; Cholesterol; Fats .
Kritchevsky, David. "Trans Unsaturated Fat in Health and Disease." In Lipids in Health and Nutrition. Edited by J. H. P. Tynan. Cambridge, U.K.: Royal Society of Chemistry, 1999.
Sebedio, J. L., and W. W. Christie, eds. Trans Fatty Acids in Human Nutrition. Dundee, Scotland: Oily Press, 1998.
Shirley C. ChenDavid Kritchevsky
A 40‐g portion (a medium thickness spread on four slices of bread) is a rich source of vitamins A and D; contains 32 g of fat (the percentage of saturated fat depends on the oils used in manufacture); supplies 290 kcal (1220 kJ). A single caterer's pat is 10 g; contains 8 g of fat; supplies 72 kcal (300 kJ).
Low‐fat spreads are made with 20–60% fat and correspondingly higher contents of air and water and less energy. A 40‐g portion of low‐fat spread contains 16 g of fat (of which typically 27% is saturated); supplies 145 kcal (610 kJ). A single caterer's pat is 10 g; contains 4 g of fat; supplies 35 kcal (150 kJ).
mar·ga·rine / ˈmärjərən/ • n. a butter substitute made from vegetable oils or animal fats.