The FDA recently changed the labeling requirements for food, now requiring that labels contain not only the amount of fat contained in food, but also the amount of what is called “trans” fat, short for trans-fatty acids. This change is prompted by the recognition that trans fat poses some health risks.
Understanding trans fat requires a brief chemistry lesson. Certain chemicals, such as fats, can occur in two similar but geometrically different forms called isomers. Isomers are basically the same chemical, but appear “backward” as if you held them in front of a mirror. These two backward shapes are the isomers, and are given the names “cis’ and “trans.”
We have told you that the preferred fats are the unsaturated fats, and the fats to be avoided are the saturated fats (“sat fat”), and that sat fat is generally solid at room temperature and unsaturated fat is generally liquid at room temperature. The problem occurs in the preparation of margarine and shortening, where normally liquid unsaturated oils, in the “cis” configuration, are partially hydrogenated to make them solid,, whereby they become more saturated and are now in the “trans” configuration.
Having said that, why are “trans” fat-containing margarines and shortenings a problem?
The problem is that even though margarine contains mainly unsaturated fat, it has been changed to the trans configuration, which behaves as if it were saturated, raising the risk of heart disease, etc. Trans fat raises LDL (so-called “bad” cholesterol) and lowers HDL (“good” cholesterol). Trans fat also interferes with the metabolism of essential fatty acids (see that section) which serve many functions, such as the formation of healthy cell membranes and the production of prostaglandins. Alterations in essential fatty acid metabolism have been linked to an increased risk of certain cancers including breast cancer.
It is for this reason that the labeling change to include trans fat was made and why our advice at Nature’s Healthcare is to avoid trans fat, so much so that we now believe it is wiser and healthier to use butter sparingly than margarine liberally, and shortening never.