Omega-3 & -6 fatty acids

By Rosalee M. Brown

Some people are confused about fats and have a negative view of this very important nutrient. Fats are not only important to body functioning but are also culinary agents.

The simplest building blocks for the nutrient fat are called fatty acids, and they are provided through the diet except for two referred to as 'essential'. These two essential fatty acids must be provided by the human diet, as the body is unable to make them. They are omega-6 and omega-3 fatty acids, types of polyunsaturated fatty acids also called PUFAs.

Omega-6 and -3 play major roles in the body, including brain development and function, normal growth and development, skin and hair growth, maintenance of the reproductive system and the regulation of metabolism. The omega-3 alpha-linolenic acid (ALA) is converted through reactions to eicosapentaenoic acid (EPA).

EPA can be directly obtained from the diet through the oils of fatty fish. EPA can be converted to docosahexaenoic (DHA) and to ecosanoids, which are important in signalling inflammation in the body. The conversion of ALA to EPA and DHA is more efficient in women than men, and can be an overall slow process in the body. It is beneficial to get EPA from food sources such as cold-water fish.

A wholesome diet contains a balance of both omega-6 and omega-3, but the Western American-style diet contains 10 to as much as 25 times more omega-6 fatty acids than omega-3. Omega-3 fatty acids are said to be more anti-inflammatory than omega-6, and therefore protective against diseases such as cardiovascular diseases. The recommended ratio of omega-6 to -3 is 2:1-4:1.

Not all omega-6 fatty acids promote inflammation. Linoleic acid (LA), the essential omega-6, is converted to gamma linoleic acid (GLA) in the body, which is further broken down to arachidonic acid, which may reduce inflammation. Omega-6 can be converted to inflammatory agents called eicosanoids. Omega-3 can also be converted to eicosanoids, but at a slower rate. Eicosanoids have a short active life in the body from synthesis to metabolism, but if the rate of synthesis exceeds metabolism, the excess can have damaging effects.

These are many more good reasons to consume fish such as sardine, mackerel, herring and tuna.

Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.

Sources of omega-6

Linoleic acid is found in vegetable oils such as corn and soybeans, and animal meats. It is especially high in non-free range animals. Arachidonic acids (AA) are found only in animal sources.

Sources of omega-3

Alpha- linolenic acids (ALA) are found in flax seeds, but are not always efficiently converted to EPA in the body.

EPA is found in fish oils

DHA in fish and fish oils