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Saturated fats and unsaturated fats

Another type of fat with not quite deserved reputation of being a "bad fat" are saturated fats. These fats are needed by the body, and become a health problem only when taken in excess - which is pretty much common to all nutrients.

What is the difference between saturated and unsaturated fats? Well, dietary lipids come either in the form of fat (solid on room temperature) or oil (liquid), depending on the nature of their building blocks - fatty acids. Fats are solid because they have higher melting point than oils; and they have higher melting point because they consist mainly from saturated fatty acids (stearic, palmitic, butyric and arachidic), whose molecules tend to aggregate and stick together.

Thus, the term "unsaturated fats" is formally incorrect, since these are, by definition, oils.

The name "saturated" comes from the molecular structure of a fatty acid, in which all carbon atoms have a single bond with each other. This makes for a maximum possible number of bonds - that is, saturation - with hydrogen atoms. On the other hand, fatty acids with one or more double bonds between their carbon atoms have fewer than the maximum possible hydrogen bonds, which makes them (hydrogen) unsaturated.

The body uses saturated fatty acids mainly as a source of energy, but also as a material (cell membranes). It obtains them either directly from the food, or by conversion from sugars and starches. It is only when the level of saturated fatty acids in the body becomes excessive that they become a health problem. And this occurs when the rate of their absorption/conversion is higher than the rate at which body burns them for the energy. Obviously, the key is in balancing your saturated lipids and carbohydrate intake with your physical activity.

Unsaturated fatty acids are entirely different story. Instead of sticking together, they tend to disperse, a property that allows them to be used for complex functions in cellular membranes. Those with a single double bond are called monounsaturated (palmitoleic acid in milk, or oleic acid in olives and most nuts), while those with two double bonds are polyunsaturated, like Omega-6 or linoleic acid (LA), which includes gamma-linolenic acid (GLA) in borage, hemp and primrose oils, and arachidonic acid in animals.

Triple double bond brings us to super-unsaturated Omega-3 fatty acids, or alpha-linolenic acid (ALA), which includes eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids.

The last two unsaturated fatty acids, Omega-6 and Omega-3 are needed for vital functions at the cellular level, but cannot be produced by the body. That makes them essential - they must be obtained from the food. Other unsaturated fats - or, more correctly, oils - are, like saturated fats, good in moderation.  R