Trans fatty acids
Unsaturated fatty acids with a modified (trans) spatial configuration, mainly produced industrially by partial hydrogenation of oils and recognised as harmful to cardiovascular health.
Trans fatty acids (TFAs) come in two forms:
- Natural trans fats: present in small amounts in dairy products and ruminant meat (through fermentation in their stomachs). Rather neutral, even beneficial (vaccenic acid)
- Industrial trans fats: created by partially hydrogenating vegetable oils to solidify them. These are the dangerous ones
Industrial trans fats were used to extend shelf life (hard margarines, industrial pastries, fast-food frying).
A fresh angle: industrial TFAs are the only type of dietary fat with no benefit at all. They raise LDL (bad cholesterol) AND lower HDL (good cholesterol), the worst of both worlds. In 2018 the WHO launched a plan (REPLACE) to eliminate them worldwide by 2023.
In Europe, since April 2021, industrial TFAs have been limited to 2 g per 100 g of fat in products. Many manufacturers have eliminated them.
The catch: the words « partially hydrogenated oil » in the ingredients list reveal their presence even if the label says « 0 g trans » (a legal loophole: below a threshold, 0 can be declared). Reading the ingredients remains crucial.