What are omega-3 fats and what is the science behind the claims relating to foods high in omega-3 fats?

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

Omega-3 fats are polyunsaturated fats that are found in significant quantities in several plants and plant oils (eg. canola, linseed, soy and walnut) and in even greater quantities in many varieties of seafood. The evidence is now quite strong that omega-3 fats are beneficial in at least three areas of human health: heart disease, inflammatory disease, and development of vision and brain function in babies.

With respect to heart disease, several risk factors are reduced in response to increased consumption of omega-3 fats, including a reduction in the level of blood triglycerides (TG). In fact, omega-3 is used to treat people with elevated TG and who suffer from pancreatic disease that does not respond to drugs.

Omega-3 fats also reduce blood clotting and so may lower the risk that a heart attack will occur, or if it does, reduce the likelihood that it will lead to fatal obstruction of a coronary artery. Eating fish regularly is associated with a reduced risk of heart disease. Surprisingly, there does not seem to be a dose-response to eating fish. That is, eating fish once a week has the same beneficial effect as eating it three or four times weekly.

Rheumatoid arthritis and other inflammatory diseases (eg psoriasis) generally respond positively to increased consumption of foods containing omega-3 fats. This promotes the formation of molecules called 'cytokines', enhancing the production of less reactive compounds.

It is also clear that a form of omega-3 known as DHA plays a major role in the development of normal vision and brain function in babies. DHA is present in human breast milk - perfectly designed for babies’ brains and visual development. DHA must be added to milk formulated for pre-term infants, but it is not yet known if it should also be added to formulae for full-term infants.

For more information Nutrition Australia recommends:

• Eat Less Fat

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[Date issued: February 1999]

Disclaimer: This material is provided on the basis that it constitutes advice of a general nature only. It is not intended to replace the advice of a physician or a dietitian.