Omega-3 saturated fatty acids

Above, 1 provided a short explanation for the recommendation to limit the dietary intake of saturated fats. That is not the only recommendation that we get from health authorities about dietary fats. Two more recommendations come to mind immediately (a) limit your intake of trans fats and (b) consume substantial amounts of omega-3 fatty acids. Let s have a look at the basis for both recommendations. 

The fatty acid content of our diet has important consequences for health. Several fatty acid are essential dietary components. In general, saturated and trans fatty acids are inimical to good health. In contrast, omega-3 fatty acids are favorable to good health. 

Aside from sophisticated drug design, there is a surprisingly simple means of favourably influencing the balance of Good and Evil in eicosanoid metabolism Eating fish. As initially mentioned, aside from arachidonic acid, other multiply non-saturated fatty acids can serve as precursors of eicosanoid mediators as well, in particular eicosapentanoic acid (EPA), which has an additional double bond between C17 and Cl8. The introduction of this omega-3 double bond does not occur, nor is it reversible, in mammalian... 

Researchers from Denmark collaborated with doctors at the University of Wollongong in New South Wales, Australia, to determine the effects of saturated, monounsaturated, and omega-3 fatty acids on blood pressure in healthy subjects. They found that decreasing the saturated fats and increasing the monounsaturated led to decreased blood pressure, but that the benefit disappeared when subjects consumed a diet that was high in fat, 37 percent of the total calories. So, as is often the case, moderation is the winning ticket. 

In contrast to the shorter chain and more saturated fatty acids, the essential fatty acids (EFAs), linoleic acid (LA, an omega-6 fatty acid, 18 2n-6), and a-linolenic acid (LNA, an omega-3 fatty acid, 18 3n-3) serve as substrates for the production... 

Fatty acid composition of regular flax oil is different from other commercial oils because of the very high contribution of ALA, usually above 50% (Table 2). Because of the high content of this unique fatty acid, flaxseed and flax oil are often used as food supplements, where enrichment with omega-3 fatty acids is needed. This fatty acid is susceptible to oxidation it oxidizes 20 0 times faster than oleic acid and 2 times faster than linoleic acid (8). This property makes the oil a good material for paint and plastic production where fast oxidation is required. Flax oil contains low amounts of saturated fatty acids (SFA) compared with low linolenic flax oil (Linola), soybean, and sunflower oils however, it is higher than canola oil (Table 2). Canola oil contains the lowest amount of SFA among all commercial oils. 

Table 5 shows the marketing and label strategies for some current marine omega-3 products sold in Halifax, Canada. Obviously samples No. 1 and No. 6 are natural oils. Perhaps No. 5 is simply winterized oil, a process demonstrated in Table 6 for menhaden oil, which follows from the tendency for DHA to be in the 2-position of fish oil triacylglycerols (81). EPA is reputed to be somewhat less specihc. In the absence of 20 1 and 22 1, the outer 1- and 3-positions may, in some molecules, present two saturated fatty acids from 14 0, 16 0, and 18 0 in one triacylglycerol molecule, which leads to the stearine composition of Table 6. 

A balance between the omega-6 and omega-3 fatty acids is a more physiologic state in terms of gene expression (Simopoulos, 1996), prostaglandin and leukotriene metabolism, and interleukin-1 (IL-1) production (Simopoulos, 1991). The current recommendation to substitute vegetable oils (omega-6) for saturated fats leads to increases in IL-1,... 

Table 10.9 and Table 10.10 summarize the effects of various PUFA on gene expression. In the case of enzymes involved in carbohydrate and lipid metabohsm, both omega-3 and omega-6 fatty aeids appear to suppress the genes that eneode for several enzymes (Table 10.9), whereas saturated, trans-, and monounsaturated fatty acids fail to suppress. DHA appears more potent in its effect than other PUFA. Omega-6 and omega-3 fatty acids and monounsaturated fatty adds induce acyl-CoA oxidase, the enzyme involved in beta-oxidation, but here again, DHA appears to be more potent. 

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