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MYTH #3:

The body can convert omega-6 fatty acids into omega-3 fatty acids as it needs.

This falsehood is akin to myth number two. Omega 3 and 6 fatty acids are polyunsaturated fats of which two, linolenic (an omega-3) and linoleic (an omega 6), are essential to human life and must be obtained from food as the body cannot synthesise them. Although very small amounts of omega 3 linolenic acid are found in whole grains and dark green leafy vegetables, it is principally found in animal foods (especially fish and eggs), as well as flax seed oil. Omega 6 linoleic acid is mostly found in vegetables, but small amounts are present in certain animal fats. To assuage vegans who fear they may not get enough omega 3 linolenic acid, some vegetarian sources assert that the body can simply convert excess omega 6 linoleic acid into omega 3 linolenic acid, and other omega 3 fatty acids such as EPA and DHA, two fatty acids intimately involved in the health of the brain and immune system.

Renowned lipid biochemist Dr Mary Enig, of the University of Maryland, and other authorities have shown that the body cannot change the omega number of fatty acids. The body can change the fatty acid's degree of saturation and also its molecular length, but not its omega number (12). In other words, omega 6 fatty acids can only be converted into other omega 6 fatty acids; omega 3s only into other omega 3s.

Again, I have seen the results of this misinformation in my practice. I've had several patients of Northern European descent with severe mental and immune problems caused by a lack of EPA and DHA, two omega-3 fatty acids not found in plant foods (DHA is found in small amounts in some algae). People native to warmer climates in the world can manufacture these fatty acids from other omega-3s, but those of Northern European or Innuit descent cannot. Since their ancestors ate so much EPA- and DHA-rich fish, their bodies eventually lost the ability to manufacture these fatty acids (13). For these people, vegetarianism is impossible; they must consume either eggs or fish in order to survive.

There is also a very real danger from consuming too many omega-6 fatty acids, principally found in vegetables. The body requires both omega-6 and omega-3 fatty acids. However, when the body's cells are overloaded with omega-6s, their ability to utilise the omega-3 is inhibited (14).
Chronically low levels of omega-3 fatty acids are associated with higher cancer rates and immune dysfunction. Excessive levels of omega-6 fatty acids are also strongly correlated with a high incidence of cardiovascular disease (as is excessive consumption of refined sugar and trans-fatty acids) [15].