omega 3, lipids, polyunsaturated fatty acids, alpha-linolenic acid, fish, oil, walnuts, rapeseed, soy, flax, blood pressure, triglycerides, cardiovascular, RDI, fatty acids, omega-3 fatty acids, nutrition, recommended dietary intakes

Omega 3

Omega-3 fatty acids belong to the family of polyunsaturated fatty acids (lipids) They are called "essential" as they help cells to function properly.
The precursor of this family, alpha-linolenic acid (ALA), is called "vital" as it is necessary for the human body to develop and function properly. The body cannot make it itself however, and we must therefore get it through our diet. The body uses ALA to make other omega-3 fatty acids, particularly long-chain polyunsaturated fatty acids including docosahexaenoic acid (DHA).

Where are omega-3 fatty acids (FAs) found?

Foods rich in omega 3 come from land plants and some marine animals:
· walnuts, rapeseed, soy, flax, etc.
· oily fish, such as salmon, tuna, mackerel, herring, sardine and anchovy. Note that farmed fish contains much less omega 3 than wild fish,
However, in France, products from land animals (meat, eggs, dairy products) are the main contributors to this intake as they are consumed in large quantity.

What are their health effects?

Scientific findings show that the consumption of omega 3 FAs can:
· reduce blood pressure in people presenting hypertension
· reduce the quantity of triglycerides in the blood, a type of lipid which can trigger heart disease if there are too many of them
· reduce cardiovascular disease and mortality levels in people who have previously presented cardiovascular diseases

This information is currently being updated in the light of new scientific data.

ANSES's work

To date, dietary reference intakes (DRIs) for omega-3 fatty acids have been defined for ALA and DHA and vary for different population groups. For adults, the DRI for ALA is 2g/day for men and 1.6g/d for women. The DRI for DHA is 120mg/day for men and 100mg/day for women.
Getting a balanced intake of omega 3 and omega 6 FAs, another family of essential FAs, is also important.
This is because both are metabolised by common enzymes with which they compete, and therefore means that consuming too much omega 6 will reduce omega 3 FA metabolisation.
As part of an overall diet, it is therefore recommended that the omega 3/omega 6 ratio be about 5, which means limiting omega 6 intake and maintaining or increasing adequate intake of omega 3.

In 2003, ANSES wrote a report on the nutritional interest of omega 3 FAs, their impact on the cardiovascular system and claims concerning them.
For this, it assessed the daily intakes of omega 3 in the French population. A precise assessment is difficult because of the limits of diet studies, although having said that, it seems that ALA intakes are inadequate and do not cover the DRIs.
ANSES subsequently recommended setting up a policy aimed at increasing the level of omega-3 fatty acid intake in the French population. With this in mind, promoting the consumption of foods that are naturally rich in omega-3 fatty acids, such as some types of fish and oil (rapeseed, walnut, etc.), could be considered in particular.

ANSEShighlights the fact that these cardiovascular disease prevention measures are not based solely on the consumption of omega-3 fatty acids, but also on a varied, balanced diet and the practice of a physical activity.
At home, some oils that are rich in omega-3 fatty acids should not be fried or heated to a high temperature, instead they should preferably be used to season dishes.

February 2009