Nutrition Science and Everyday Application - beta v 0.1

FATTY ACID TYPES AND FOOD SOURCES 275
Figure 5.20. Comparison of a saturated fatty acid to both the cis and trans forms of an
unsaturated fatty acid.
Hydrogenation was developed in order to make oils semi-solid at room temperature,
enabling production of spreadable margarine and shortening from inexpensive ingredients
like corn oil. Hydrogenation also makes oils more stable and less likely to go rancid, so
partially hydrogenated oils were favored by fast food restaurants for frying, and
manufacturers of processed baked goods like cookies and chips found they gave their
products a longer shelf life. And because trans fats are unsaturated, nutrition scientists and
the medical community believed that they were a healthier alternative to saturated fats.
But around the 1990s, evidence that trans fats were not healthy—far worse than saturated
fats, in fact—began to accumulate. Like saturated fat, trans fats increase LDL (“bad”)
cholesterol, but they also have the effect of decreasing HDL (“good”) cholesterol and
of increasing inflammatory processes in the body. Researchers found that consuming trans
fats, even at low levels (1 to 3 percent of total energy intake), was associated with an