Trans Fatty Acid, lipids, bad cholesterol , cholesterol, cardiovascular risk, stabiliser, preservative, label, dairy products, milk, meat, ruminant fat, processed foods, solid, hydrogenated

Trans fatty acids belong to the lipid family and more specifically to the unsaturated fatty acids group, (i.e. chemically speaking, they contain at least one double bond). Their name is related to the fact that their double bond is located in the 'trans' position.

Where do trans fatty acids come from?

These compounds can form in very different ways:
- Some trans fatty acids are said to be natural. They are created in the stomachs of ruminants (cows, sheep) by bacteria in these animals' rumens. The compounds then pass into the animals' body fat and milk. As a result, they can be found in meat, milk and dairy products.
- Other trans fatty acids are artificial. They are synthesised via industrial processes such as the hydrogenation of vegetable oils. Fats can therefore be transformed from liquid to solid state, which facilitates their use and storage and makes them less sensitive to oxidation.
- They can also form when vegetable oils are heated or cooked at high temperatures, whether for industrial processing or domestic use.

Which products contain trans fatty acids?

The main dietary sources of natural trans fatty acids are dairy products and meat.
Artificial trans fatty acids are used in the food processing industry as stabilisers and preservatives. They make foods firmer and more stable, and therefore less likely to go stale. They can also be found in a wide variety of processed foods such as viennoiserie (sweet breads), pizzas and quiches.
Industrial bread products, viennoiserie and biscuits are thus the second largest source of trans fatty acid intake. Other products that contain trans fatty acids include household margarine, chocolate bars and some ready-made meals.

How do trans fatty acids affect human health?

Epidemiological studies have shown that an excessive consumption of trans fatty acids (intake greater than 2% of total energy intake) is related to increased cardiovascular risk. Trans fatty acids can increase levels of "bad" cholesterol and decrease levels of "good" cholesterol.
However, no increased cardiovascular risk has been identified in relation to the consumption of trans fatty acids of natural origin at the consumption levels currently observed in France.
Some studies suggest that artificial trans fatty acids could specifically be responsible for increased risk of cardiovascular disease. This cause-and-effect relationship is still being investigated. However, the increased risk highlighted by these studies could, at the very least, be related to excess intake when artificial trans fatty acids are added to vectors of natural origin.

Agency's recommendations

In light of the above information, AFSSA recommends:
- limiting total intake of trans fatty acids to less than 2% of total energy intake
- and in particular, reducing the consumption of some of the main foods that contain artificial trans fatty acids (viennoiserie, pastries, industrial bread products, chocolate bars, biscuits)
- continuing efforts to reduce the use of artificial trans fatty acids, both in human food and in animal feed;

November 2009