Trans Fatty Acid Fact Sheet
(Including Hydrogenated and Partially Hydrogenated Fats)
What are Trans Fatty Acids?
Trans fatty acids are abnormal fats, often called “plastic fat,” produced mainly from partial hydrogenation of vegetable oils. These fats do not occur in nature. They were introduced into human foods in the U.S. beginning in 1910. Greater amounts of partially hydrogenated vegetable fat products were added to human foods 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. Although trans fatty acids have been largely ignored during the early decades of their use, several researchers became concerned, beginning in the 1950s. Since 1990, they have become a major concern for many nutritionists and are a prominent topic in the current bio-medical literature.
Adapted from Mary G. Enig, Ph.D., F.A.C.N. Director, Nutritional Sciences Division Enig Associates, Inc., “Trans Fatty Acid Fact Sheet,” 1995.
Common Sources of Trans Fatty Acids (in commercial foods):
found in margarine, mayonnaise, salad dressing, bread, pretzels, chips, bagels, buns, rolls, cookies, cakes, soup, cheese spreads, many types of pastries and baked goods, many candy bars and “health food” candy bars, chocolate, many nutritional supplements (used as an excipient).
Adverse Effects of Consuming Trans Fatty Acids
(Studies on humans and animals)
- Lowers the “good” HDL cholesterol (the more trans fats you eat, the lower your HDL cholesterol)
- Raises the LDL cholesterol, “the bad fat fraction” (the more trans fats you eat, the higher your LDL cholesterol)
- Raises the atherogenic lipoprotein-a in humans
- Raises total serum cholesterol levels (20-30 mg%)
- Lowers the amount of cream in milk from lactating females, thus lowering the overall quality of good fat available to the infant (humans and animals)
- Correlates to low birth weight in human infants
- Increases insulin levels in response to glucose load, increasing risk for diabetes (in humans)
- Affects immune response by lowering efficiency of B cell response and increasing proliferation of T cells
- Decreases levels of testosterone in male animals; increases level of abnormal sperm, and interferes with gestation in females
- Decreases the response of the red blood cell to insulin, thus having a potentially undesirable effect in diabetics
- Inhibits the function of membrane-related enzymes such as the delta-6 desaturase, resulting in decreased conversion of, e.g., linoleic acid to arachidonic acid
- Causes adverse alterations in the activities of the important enzyme system that metabolizes chemical carcinogens and drugs (medications), i.e., the mixed function oxidase cytochromes P-448/450
- Negatively alters the physiological properties of biological membranes, including measurements of membrane transport and membrane fluidity
- Negatively alters adipose cell size, cell number, lipid class, and fatty acid composition
- Adversely interacts with conversion of plant Omega-3 fatty acids to elongated Omega-3 tissue fatty acids
- Increases adverse effects of essential fatty acid deficiency
- Increases peroxisomal activity (increases free-radical formation)