n−9 fatty acids (popularly referred to as ω−9 fatty acids or omega-9 fatty acids) are a family of unsaturated fatty acids which have in common a final carbon–carbon double bond in the n−9 position; that is, the ninth bond from the end of the fatty acid.

[edit] Background

Some n−9s are common components of animal fat and vegetable oil. Two n−9 fatty acids important in industry are:

• Oleic acid (18:1, n−9), which is a main component of olive oil and other monounsaturated fats
• Erucic acid (22:1, n−9), which is found in rapeseed, wallflower seed, and mustard seed. Rapeseed with high erucic acid content is grown for commercial use in paintings and coatings as a drying oil.

Unlike n−3 and n−6 fatty acids, n−9 fatty acids are not classed as essential fatty acids (EFA). This is both because they can be created by the human body from unsaturated fat, and are therefore not essential in the diet, and because the lack of an n−6 double bond keeps them from participating in the reactions that form the eicosanoids.

Under severe conditions of EFA deprivation, mammals will elongate and desaturate oleic acid to make mead acid, (20:3, n−9).^[1] This also occurs to a lesser extent in vegetarians and semi-vegetarians.^[2]

[edit] Potential negative health effects

Oleic and monounsaturated fatty acids were positively associated with breast cancer risk. The saturation index was inversely associated with breast cancer risk [declining with saturation increase]. Monounsaturated fats and saturation index in erythrocyte membranes are predictors of postmenopausal breast cancer. Both of these variables depend on the activity of the enzyme 9-d delta 9 desaturase.^[3]

[edit] List of n−9 fatty acids

[edit] See also

• Polyunsaturated fatty acid, lists of fatty acids including n−3, n−6, and n−9 fatty acids
• n−3 fatty acid
• n−6 fatty acid

[edit] References

[edit] Additional references