Q: I understand the FDA is going to limit trans fats. Can you discuss what the replacement will be, and whether there are any health implications?
I applaud the move to ban trans fats. It already has the food industry scrambling to find replacements. But unfortunately, those replacements might be just as bad as trans fats.
There are only two practical options for replacing synthetic trans fatty acids (TFAs) in foods. First, food manufacturers could go back to simply using natural saturated fats. They are found in nature and in natural dietary sources.
Option number two is to modify fats by hardening them, through a process called inter-esterification (IE). Mainly two saturated fatty acids (IE 18 and IE 16) have been inter-esterified to harden oils. Food scientists use the IE 16 from fully hydrogenated palm oil or IE 18 from fully hydrogenated soybean oil.
Both these non-TFA types of fats have been studied for their effects on cardiovascular diseases for the past 40 years. The results have been mixed. Some studies revealed negative effects on lipoproteins, blood glucose, immune function, and liver enzymes.
Researchers have concluded that we need to learn a lot more about IE fat consumption before it becomes embedded in the food supply as a replacement for TFA.
But the bigger point is that there is no reason to include foods that contain TFAs—or any of their potential replacements—in a healthy diet in the first place. Whether TFAs are replaced with saturated fats, palm oil or IEs, they are not foods we should be eating. These kinds of fats are needed to artificially “harden” fats in various processed foods. But healthy foods don’t need their fats to be hardened.