Fat, saturated fat and trans fatty acids

Lipids or fats are the third major class of nutrients after carbohydrate and protein. They provide a structural role, because the lipids are essential components of cell membranes, and an energetic role.

Lipids are in fact an energy reserve, stored in adipose tissue. Lipids in the body are divided into many classes to which molecules such as triglycerides, the cholesterol and fatty acids.
Fatty acids are divided into:

Saturated fatty acids

All carbon atoms of the molecule are saturated with hydrogen. They have the property "to be solid at room temperature, like butter.

They are mostly fats "Animal:

- monounsaturated fatty acids : two consecutive carbon atoms of the molecule are linked by a double bond. For example, oleic acid, found in olive oil is a monounsaturated fatty acid. They have the ability to be fluid at room temperature.

- polyunsaturated fatty acids : several consecutive atoms are linked by double bonds. Found in this class linoleic acid (which belongs to the family of omega 6) and alpha-linolenic acid (which belongs to the family of omega 3), which are essential fatty acids, whose intake from food is essential.

Trans fatty acids (or trans fat)

Trans fatty acids are natural fatty acids found in meat or milk, and are the result of a small chemical modification.

These are monounsaturated fatty acids (having a double bond between carbon atoms), but their spatial configuration is different (so-called position "trans"). This small change, achieved through a process called hydrogenation of vegetable oils and seemingly insignificant fatty acids gives the possibility to be less fluid or solid at cold, what is the effect sought by the industry. Indeed, trans fatty acids provide a better storage stability to products in which they are used, such as bread, pastries, cakes, cookies, pizza dough, margarines etc..

However, trans fatty acids have proved dangerous, at least as much if not more, than the fatty acids of animal fats. Studies have shown that trans fatty acids consumed in excess promote cardiovascular disease and possibly breast cancer. In Canada, their presence must be indicated on the packaging of foods that contain them.

In New York, trans fats are banned in restaurants since July 1, 2008.

Trans fatty acids: a public health problem

According to the French Agency for Food Safety (AFSSA), the consumption of trans fats from foods or processed should not exceed 2% of total daily energy intake, between three and four grams / day . Now it turns out that this rate is often exceeded, especially among adolescents are major consumers of products containing trans fatty acids (pastries, candy bars, etc.).

The solution is voluntarily limiting consumption of trans and by reducing the use of these products to manufacturing, not to exceed 1 g of trans fatty acids per 100 g of final product, no increase Furthermore saturated fatty acids. Some countries have decided to go further: the City of New York, which had already banned trans fats in cooking oils, has decided to simply ban their use in all types of food.

Now trans fats should represent more than 0.5% of the food portion, corresponding to naturally occurring trans fatty acids.