Hydrogenated or partially hydrogenated fat - What's that mean?

Hydrogenated fat

Hydrogenation produces artificially saturated fats and partially hydrogenated fats (E.g. Trans fats)

Hydrogenation (saturation) of unsaturated oils retards or eliminates the potential for these oils to go rancid for several years, makes a product “stiffer”, and also provides spreadability, texture and "mouth feel".    Unsaturated fats exposed to light, heat or air otherwise tend to oxidize and go rancid easily.

Hydrogenation is a commercial chemical process.   Patented in Germany in 1902, hydrogenation decreases the number of double bonds in unsaturated fatty acids of predominately unsaturated oils, such as soybean, corn or sunflower oil, these fully refined oils are then heated to high temperatures (248°-410°F) with metal catalysts, usually nickel or 50/50 nickel/aluminum, in the presence of pressurized hydrogen gas. (The aluminum is a concern since its presence in the body is associated with Alzheimer's, osteoporosis + more). This enables the hydrogen to be added into (i.e. saturate) the double bonds of the unsaturated fatty acids, and since they then contain no double bonds, makes them relatively chemically inert.

Hydrogenated Fatty Acid

Hydrogenated fats also contain partially hydrogenated fats, such as trans fats.    Since the hydrogenation process never achieves 100% efficiency, leaving some partially hydrogenated (altered/toxic) fats.

Foods containing hydrogenated fats - include margarine, shortening (E.g. Crisco®)

Partially hydrogenated fat  

Partial hydrogenation produces altered/toxic fatty acids (E.g. Trans Fats)

Fully saturated fats are usually too waxy and solid to add to food processing steps.   So manufacturers typically require partially hydrogenated oils, for which the hydrogenation process is stopped when the oil has the proper consistency for its application. This process is used to make products like chocolate, "hard enough to melt in your mouth, but not in your hand!" Unfortunately, the partial hydrogenation process also results in the presence of dozens of altered, intermediate substances including trans fats, conjugated fatty acids, double bond isomers (double bonds relocated to new, unnatural positions) and fatty acid fragments.

A NATURAL, unsaturated fatty acid is in what is called the CIS configuration.    With the hydrogen atoms at a double bond on the same side of the molecule. This lack of symmetry forces a kink or bend in the carbon chain

CIS Fatty Acid

A TRANS configuration fatty acid is produced by heat-processing during hydrogenation, frying in unsaturated oils, and the high temperatures in the oil refining process.   When a hydrogen atom TRANSfers to the other side of the fatty acid molecule. The TRANS configuration fatty acid has only a slight kink in its carbon chain. tFAs begin to form above 320°F, and form in substantial quantities above 392 °F.

Trans Fatty Acid

High levels of 30-50% trans fatty acids are commonly found in these oils:

•    Highly processed oils.    E.g. margarine, shortening

•    Oils used for repeated frying.   In restaurants oils (called "liquid shortening")

•   "Partially-hydrogenated vegetable oils".     Found in ready-made french fries and many packaged goods, such as commercially processed foods/ Foods with a long shelf-life - such as cookies, cakes, crackers, bread, candies, most peanut butter, pancake mixes, instant soups, chocolate, some salad dressings, junk foods, chips, croutons, granola bars.