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''Trans'' fats, or trans-unsaturated fatty acids, trans fatty acids, are a type of unsaturated fats that are uncommon in nature but became commonly produced industrially from vegetable fats for use in margarine, snack food, packaged baked goods and frying fast food starting in the 1950s.〔〔〔http://www.regulations.gov/contentStreamer?objectId=09000064817e82ec&disposition=attachment&contentType=pdf〕 Trans fat has been shown to consistently be associated, in an intake-dependent way, with risk of coronary heart disease, the worldwide leading cause of death.〔(【引用サイトリンク】title=Mar 8 2014 FDA filing by HARVARD SCHOOL OF PUBLIC HEALTH – on the Tentative Determination Regarding Partially Hydrogenated Oils; Request for Comments and for Scientific Data and Information )〕 Fats contain long hydrocarbon chains, which can either be unsaturated, i.e. have double bonds, or saturated, i.e. have no double bonds. In nature, unsaturated fatty acids generally have ''cis'' as opposed to ''trans'' configurations. In food production, liquid ''cis''-unsaturated fats such as vegetable oils are hydrogenated to produce saturated fats, which have more desirable physical properties, e.g. they melt at a desirable temperature (30–40 °C). Partial hydrogenation of the unsaturated fat converts some of the ''cis'' double bonds into ''trans'' double bonds by an isomerization reaction with the catalyst used for the hydrogenation, which yields a trans fat.〔(【引用サイトリンク】 About Trans Fat and Partially Hydrogenated Oils )〕〔 Although ''trans'' fats are edible, consumption of ''trans'' fats has shown to increase the risk of coronary heart disease in part by raising levels of the lipoprotein LDL (so-called "bad cholesterol"), lowering levels of the lipoprotein HDL ("good cholesterol"), increasing triglycerides in the bloodstream and promoting systemic inflammation.〔(【引用サイトリンク】publisher=Mayo Foundation for Medical Education and Research (MFMER) )〕 ''Trans'' fats also occur naturally in a limited number of cases. Vaccenyl and conjugated linoleyl (CLA) containing ''trans'' fats occur naturally in trace amounts in meat and dairy products from ruminants. Most artificial ''trans'' fats are chemically different from natural ''trans'' fats. Two Canadian studies〔(Trans Fats From Ruminant Animals May Be Beneficial – Health News ). redOrbit (8 September 2011). Retrieved 2013-01-22.〕 have shown that the natural ''trans'' fat vaccenic acid, found in beef and dairy products, could actually be beneficial compared to hydrogenated vegetable shortening, or a mixture of pork lard and soy fat,〔 by lowering total and LDL and triglyceride levels. A study by the US Department of Agriculture showed that vaccenic acid raises both HDL and LDL cholesterol, whereas industrial ''trans'' fats only raise LDL without any beneficial effect on HDL.〔David J. Baer, PhD. US Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Laboratory. (''New Findings on Dairy Trans Fat and Heart Disease Risk'' ), IDF World Dairy Summit 2010, 8–11 November 2010. Auckland, New Zealand〕 In light of recognized evidence and scientific agreement, nutritional authorities consider all ''trans'' fats as equally harmful for health and recommend that consumption of ''trans'' fats be reduced to trace amounts. In 2013, the United States Food and Drug Administration (FDA) issued a preliminary determination that partially hydrogenated oils (which contain ''trans'' fats) are not "generally recognized as safe", which was expected to lead to a ban on industrially produced ''trans'' fats from the American diet. On 16 June 2015, the FDA finalized its determination that trans fats are not generally recognized as safe, and set a three-year time limit for their removal from all processed foods.〔(【引用サイトリンク】title=The FDA takes step to remove artificial trans fats in processed foods )〕 In other countries, there are legal limits to ''trans'' fat content. ''Trans'' fats levels can be reduced or eliminated using saturated fats such as lard, palm oil or fully hydrogenated fats, or by using interesterified fat. Other alternative formulations can also allow unsaturated fats to be used to replace saturated or partially hydrogenated fats. Hydrogenated oil is not a synonym for ''trans'' fat: complete hydrogenation removes all unsaturated fats. ==History== Nobel laureate Paul Sabatier worked in the late 1890s to develop the chemistry of hydrogenation, which enabled the margarine, oil hydrogenation, and synthetic methanol industries.〔 Reprinted online: (【引用サイトリンク】publisher=Nobel Foundation )〕 Whereas Sabatier considered hydrogenation of only vapors, the German chemist Wilhelm Normann showed in 1901 that liquid oils could be hydrogenated, and patented the process in 1902. During the years 1905–1910, Normann built a fat-hardening facility in the Herford company. At the same time, the invention was extended to a large-scale plant in Warrington, England, at ''Joseph Crosfield & Sons, Limited.'' It took only two years until the hardened fat could be successfully produced in the plant in Warrington, commencing production in the autumn of 1909. The initial year's production totalled nearly 3,000 tonnes.〔(【引用サイトリンク】title=Wilhelm Normann und die Geschichte der Fetthärtung von Martin Fiedler, 2001 )〕 In 1909, Procter & Gamble acquired the US rights to the Normann patent; in 1911, they began marketing the first hydrogenated shortening, Crisco (composed largely of partially hydrogenated cottonseed oil). Further success came from the marketing technique of giving away free cookbooks in which every recipe called for Crisco. Normann's hydrogenation process made it possible to stabilize affordable whale oil or fish oil for human consumption, a practice kept secret to avoid consumer distaste.〔 Prior to 1910, dietary fats consisted primarily of butterfat, beef tallow, and lard. During Napoleon's reign in France in the early 19th century, a type of margarine was invented to feed the troops using tallow and buttermilk; it did not gain acceptance in the U.S. In the early 20th century, soybeans began to be imported into the U.S. as a source of protein; soybean oil was a by-product. What to do with that oil became an issue. At the same time, there was not enough butterfat available for consumers. The method of hydrogenating fat and turning a liquid fat into a solid one had been discovered, and now the ingredients (soybeans) and the "need" (shortage of butter) were there. Later, the means for storage, the refrigerator, was a factor in trans fat development. The fat industry found that hydrogenated fats provided some special features to margarines, which allowed margarine, unlike butter, to be taken out of the refrigerator and immediately spread on bread. By some minor changes to the chemical composition of hydrogenated fat, such hydrogenated fat was found to provide superior baking properties compared to lard. Margarine made from hydrogenated soybean oil began to replace butterfat. Hydrogenated fat such as Crisco and Spry, sold in England, began to replace butter and lard in the baking of bread, pies, cookies, and cakes in 1920. In the 1940s, Catherine Kousmine researched the effects of trans fats on cancer.〔(【引用サイトリンク】title=Trans Fat History )〕 Production of hydrogenated fats increased steadily until the 1960s, as processed vegetable fats replaced animal fats in the US and other western countries. At first, the argument was a financial one due to lower costs; advocates also said that the unsaturated trans fats of margarine were healthier than the saturated fats of butter. As early as 1956 there were suggestions in the scientific literature that ''trans'' fats could be a cause of the large increase in coronary artery disease but after three decades the concerns were still largely unaddressed.〔 In fact, by the 1980s, fats of animal origin had become one of the greatest concerns of dieticians. Activists, such as Phil Sokolof, who took out full page ads in major newspapers, attacked the use of beef tallow in McDonald's french fries and urged fast-food companies to switch to vegetable oils. The result was an almost overnight switch by most fast-food outlets to switch to trans fats. Studies in the early 1990s, however, brought renewed scrutiny and confirmation of the negative health impact of trans fats. In 1994, it was estimated that trans fats caused 20,000 deaths annually in the US from heart disease. Mandatory food labeling for ''trans'' fats was introduced in several countries. Campaigns were launched by activists to bring attention to the issue and change the practices of food manufacturers. In January 2007, faced with the prospect of an outright ban on the sale of their product, Crisco was reformulated to meet the United States Food and Drug Administration definition of "zero grams trans fats per serving" (that is less than one gram per tablespoon, or up to 7% by weight; or less than 0.5 grams per serving size)〔〔〔〔 by boosting the saturation and then diluting the resulting solid fat with unsaturated vegetable oils. A University of Guelph research group has found a way to mix oils (such as olive, soybean and canola), water, monoglycerides and fatty acids to form a "cooking fat" that acts the same way as trans and saturated fats. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「trans fat」の詳細全文を読む スポンサード リンク
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