The food we eat contains various types of fat. Some fats such as omega-3 are essential to maintain good health.
The role of fat in the body
To become more familiar with omega-3, we need to know that they belong to the lipid family. Better known as fat, lipids are an essential part of a balanced diet. For instance, they help our body to produce cells and are involved in the proper functioning of our nervous system. They are also a privileged source of energy. In fact, they supply twice as much energy to our body than proteins and carbohydrates.
The various categories of fat
This extended lipid family is made up of saturated fats and unsaturaded fats, among which are found monounsaturated and polyunsaturated fats. This distinction occurs according to their chemical characteristics, i.e. based on their number of double bonds (specific bonds between two atoms). When no double bond is present, they are called saturated fatty acids. When only one double bond is present, they are called monounsaturated. When several double bonds are present, they are called polyunsaturated fatty acids.
The two families
Amongst polyunsaturated fatty acids, we find two families: omega-3 and omega-6. Their generic names are based on the location of the double bond on their molecule. Each one has its own distinct properties.
Omega-3 and omega-6 fatty acids are called essential fatty acids because our body cannot synthesize them. They must absolutely be supplied by the food we eat.
Omega-3 sources
The omega-3 family is composed of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
ALAs, which come from plants, are found in oils as well as in flax, pumpkin and hemp seeds, in walnuts and their oil as well as in oils such as canola and soy oil.
AEPs and ADHs are found in fatty fish (salmon, mackerel, herring, sardine and rainbow trout) and in their oils.
Benefits of omega-3 fatty acids
Omega-3 fatty acids protect you against heart disease by:
- Reducing the amount of bad cholesterol in your blood, which is caused for instance by trans fats and saturated fats. 1
- Preventing blood clotting and consequently, the development of clots in the blood that could obstruct your arteries and lead to a heart attack. 1
- Reducing triglycerides, a type of fat which, when found in excessive amounts in the blood, is responsible for the development of some heart diseases. 1
The relationship between depression and the risk for heart disease, and the double role that omega-3 fatty acids can play in preventing and treating these conditions, are becoming increasingly obvious. 2
Omega-3 fatty acids also play a positive role in:
- Reproductive and growth processes 1
- Blood cell membrane development 1
- Skin health (better regeneration following inflammation or injury) 1
- Anti-inflammatory reactions 1
Omega-3 to omega-6 ratio
Unlike omega-3 fatty acids, omega-6 are abundantly present in our modern diet. It is thus important to increase the amount of omega-3 in our diet in order to reach a proper omega-3 to omega-6 ratio. 3
Recommendations
Omega-3 fatty acids and their properties are the subject of hundreds of research studies every year, which cause nutritional recommendations to evolve and to be updated. At the present time, there is no consensus between international experts and Canadian and American recommendations.
Nevertheless, the American Heart Association recommends that healthy adults: 1
- Take at least 2 fish meals (especially fatty fish) per week
- Also include a source of omega-3 fatty acids of vegetal origin (oils and foods with high contents of alpha-linolenic acid (ALA)).
Naturally, omega-3 fatty acids combined with regular physical activity and a healthy diet will contribute to improve your health.
References
• Les lipides, Extenso, Centre de référence en nutrition, août 2005
• Dépression et maladies cardiaques, les Oméga 3 à la rescousse, Dr. François L'espérance, CHUM avril 2005
• Michel Lucas, M, Sc, Dt.p épidémiologiste/nutritionniste, Chaire de l'université Laval pour l'avancement d'une approche intégrée en santé, SFA-CHUQ, 2005, Passeport santé juillet 2005
• Michel Lucas, M, Sc, Dt.p épidémiologiste/nutritionniste, Chaire de l'université Laval pour l'avancement d'une approche intégrée en santé, SFA-CHUQ, 2005, Passeport santé âoût 2005
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