This is the process that turns polyunsaturated, normally liquid at room temperature, into fats that are solid at room temperature—margarine and shortening. To produce them, manufacturers begin with the cheapest oils—soy, corn, cottonseed or canola, already rancid from the extraction process—and mixes them with tiny metal particles—usually nickel oxide. The oil with its nickel catalyst is then subjected to hydrogen gas in a high-pressure, high-temperature reactor.
During food processing, fats may undergo a chemical process known as hydrogenation (hi”dro-jen-A’shun or hi-DROJ’en-a”shun). This changes liquid oil, naturally high in unsaturated fat, to a more solid and more saturated form. The greater the hydrogenation, the more saturated the fat becomes. Many commercial products contain hydrogenated or partially hydrogenated vegetable oils.
The hydrogenation process that creates margarine allows an oil to be partially hardened and molded into tub or stick form. Fat for shortening can be hydrogenated to give it a creamy consistency. Hydrogenation also increases the time it takes before oils become rancid, so they stay fresh longer.
Unlike butter or virgin coconut oil, hydrogenated oils contain high levels of trans fats. A trans fat is an otherwise normal fatty acid that has been “transformed”, by high-heat processing of a free oil. The fatty acids can be double-linked, cross-linked, bond-shifted, twisted, or messed up in a variety of other ways. Trans fats are poisons just like arsenic or cyanide. They interfere with the metabolic processes of life by taking the place of a natural substance that performs a critical function. And that is the definition of a poison. Your body has no defense against them, because they never even existed in our two billion years of evolution — so we’ve never had the need or the opportunity to evolve a defense against them. Partially hydrogenated oils will not only kill you in the long term by producing diseases like multiple sclerosis and allergies that lead to arthritis, but in the meantime they will make you fat!
Trans fatty acids that are products mainly of partial hydrogenation of vegetable oils were introduced into human foods in the U.S. beginning in 1910. Greatly increased amounts of partially hydrogenated vegetable fat products were added to human diets in the U.S. beginning in the 1950s. Major sources of trans fatty acids in some countries are partially hydrogenated marine oils, which were recently granted GRAS status in the U.S. The trans fatty acids were ignored during the early decades of their use; they became a focus of concern for a few researchers beginning in the 1950s, and since 1990 they have been a prominent topic in the biomedical and fats and oils literature.
Refined vegetable oils from which they are made because of chemical changes that occur found in nature. With hydrogenation, one hydrogen atom of the pair is moved partially during the hydrogenation process. Under high temperatures, the nickel catalyst causes the hydrogen atoms to change position on the fatty acid chain. Before hydrogenation, pairs of hydrogen atoms occur causing the chain to bend slightly and creating a concentration of electrons at the site of the double bond. This is called the cis formation. Hydrogenated margarines and shortenings are even worse for you than the highly together on the chain; the configuration most commonly causes the hydrogen atom to move the other side of the molecule so that the molecule straightens. This is called the trans formation, rarely found in nature. Most of these man-made trans fats are toxins to the body, but unfortunately your digestive system does not recognize them as such. Instead of being eliminated, trans fats are incorporated into cell membranes as if they were cis fats—your cells actually become partially hydrogenated! Once in place, trans fatty acids with their misplaced hydrogen atoms wreak havoc in cell metabolism because chemical reactions can only take place when electrons in the cell membranes are in certain arrangements or patterns, which the hydrogenation process has disturbed.