Plant oil in the context of "Omega-3"

Cutting fluid is a type of coolant and lubricant designed specifically for metalworking processes, such as machining and stamping. There are various kinds of cutting fluids, which include oils, oil-water emulsions, pastes, gels, aerosols (mists), and air or other gases. Cutting fluids are made from petroleum distillates, animal fats, plant oils, water and air, or other raw ingredients. Depending on context and on which type of cutting fluid is being considered, it may be referred to as cutting fluid, cutting oil, cutting compound, coolant, or lubricant.

Most metalworking and machining processes can benefit from the use of cutting fluid, depending on workpiece material. Common exceptions to this are cast iron and most types of brass, which may be machined dry.

omega−3 oils, ω−3 fatty acids or n−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond three atoms away from the terminal methyl group (numbered ω, the last letter of the Greek alphabet) in their chemical structure. They are widely distributed in nature, are important constituents of animal lipid metabolism, and play an important role in the human diet and in human physiology. The three types of omega−3 fatty acids involved in human physiology are α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA can be found in plants, while DHA and EPA are found in algae and fish. Marine algae and phytoplankton are primary sources of omega−3 fatty acids. DHA and EPA accumulate in fish that eat these algae. Common sources of plant oils containing ALA include walnuts, edible seeds and flaxseeds as well as hempseed oil, while sources of EPA and DHA include fish and fish oils, and algae oil.

Almost without exception, animals are unable to synthesize the essential omega−3 fatty acid ALA and can only obtain it through diet. However, they can use ALA, when available, to form EPA and DHA, by creating additional double bonds along its carbon chain (desaturation) and extending it (elongation). ALA (18 carbons and 3 double bonds) is used to make EPA (20 carbons and 5 double bonds), which is then used to make DHA (22 carbons and 6 double bonds). The ability to make the longer-chain omega−3 fatty acids from ALA may be impaired in aging. In foods exposed to air, unsaturated fatty acids are vulnerable to oxidation and rancidity.