Dietary oleic acid

Ruiz-Gutierrez, V., Muriana, F. J., Guerrero, A., Cert, A. M. Villar, J. (1996). Plasma lipids, erythrocyte membrane lipids and blood pressure of hypertensive women after ingestion of dietary oleic acid from two different sources. Journal of Hypertension, 14(12), 1483-90. 

The last essential dietary components to which we will refer and which were also discovered through feeding experiments with rats, are certain unsaturated fatty acids identified as linoleic, linolenic, and arachidonic acids by Burr and Burr in 1930. The acids are required for the formation of complex lipids which are essential in membranes for the maintenance of their fluidity (Chapter 9). Deficiencies lead to a dermatitis which does not respond to additional B vitamin supplements or to oleic acid. 

Note that the term trans fats refers to fats containing trans fatty acids. At a couple of points earlier, 1 emphasized that aU the common unsaturated fatty acids possess cis carbon-carbon double bonds. It is true that some common foods—beef and dairy products—contain very small amounts of trans fatty acids but it is also true that the vast preponderance of dietary trans fats come from processed foods. Here is one example of a normal cis fatty acid—oleic acid—and its trans isomer ... 

CN198 Prieto, R. M., W. Stremmel, C. Sales, and J. A. Tur. Effect of dietary fatty acids on jejunal and ileal oleic acid uptake by rat brush border membrane vesicles. Eur J Med Res 1996 1(7) 355-360. 

Emken, E.A., Adlof, R.O., Duval, S.M., and Nelson, G.J. 1999. Effect of dietary docosahexaenoic acid on desaturation and uptake in vivo of isotope-labeled oleic, linoleic, and linolenic acids by male subjects. Lipids 34, 785-791. 

Rebole, A., Rodriguez, M.L., Ortiz, L.T., Alzueta, C., Centeno, C., Viveros, A., Brenes, A. and Arija, I. (2006) Effect of dietary high-oleic acid sunflower seed, palm oil and vitamin E supplementation on broiler performance, fatty acid composition and oxidation susceptibility of meat. British Poultry Science 47, 581-591. 

Chan, J.K., Bruce, V.M., and McDonald, B.E. 1991. Dietary-linolenic acid is as effective as oleic acid and linoleic acid in lowering blood cholesterol in normolipidemic men. Am. J. Clin. Nutr. 53, 1230-1240. 

The net result of these processes is that the fatty acids in the mammary gland, which originate from the dietary lipids, consist of substantial quantities of 16 0, 18 0 and oleic acid, small amounts of linoleic and linolenic acids, and limited quantities of other monoenoic and dienoic fatty acids such as llt-18 l and 9c, llt-18 2. 

Dietary LA and ALA are metabohzed by the same set of A and desaturases and elongases to their respective metabolites (see Fig. 2), and, hence, these two fatty acids compete with one another for the same set of enzymes. A and A desaturases prefer i -3 to co-6. Oleic acid (OA, to-9) that is not an EFA also is metabolized by the same A and A desaturases. But in view of the preference of these enzymes to LA and ALA under normal physiologic conditions, the metabolites of co-9... 

The degree of rumen-mediated fatty acid modification varies from species to species. For example, the biohydrogenation of dietary unsaturates is greater in sheep than in cattle, and thus mutton tallow contains 5% to 10% more stearic acid, and a correspondingly lower amount of oleic acid, than beef tallow. Table 1 illustrates this trend, although it is somewhat obscured by the necessarily wide ranges of values reported. 

It is now known that not all saturated fatty acids are equally hypercholesterole-mic. For example, medium-chain saturated fatty acids of carbon length 8-10, as well as stearic acid (18 0), have little or no effect on serum cholesterol concentrations. In contrast, evidence indicates that palmitic acid (16 0), the principle fatty acid in most diets, can increase serum cholesterol concentrations in humans. However, in normocholesterolemic humans, dietary palmitic and oleic acids have been shown to exert similar effects on serum cholesterol, suggesting that only humans or animal species sensitive to dietary cholesterol and selected fats ( hyperresponders ) may exhibit significant changes in semm cholesterol in response to dietary fat intake. Myristic acid (14 0) and, to a lesser extent, lauric acid (12 0), which are relatively high in coconut oil, both can raise serum cholesterol and LDL-cholesterol levels. Overall, it is not clear why humans respond so differently to cholesterol or... 

There, also, is interest in dietary monounsaturated fatty acids because of their possible protective effect against oxidation of LDL cholesterol (101). There is appreciable evidence that the uptake of LDL cholesterol and the formation of fatty streaks in the intima of large blood vessels, which is considered an early lesion of atherosclerosis, is enhanced by the oxidation of the LDL cholesterol (102, 103). LDL cholesterol was found to be appreciably more stable to oxidation when subjects were fed diets rich in oleic acid than when fed linoleic acid enriched diets (104-106). 

Canola oil is characterized by a low level of saturated fatty acids (less than 4% palmitic acid) and relatively high levels of oleic acid (60%) and a-linolenic acid (10%). It is second only to olive oil, among the common fats and oils, in oleic acid level and, except for soybean oil, the only common dietary fat that contains a significant amount of a-linolenic acid. Furthermore, there is a favorable balance in the levels of linolenic and linoleic acids (viz., 18 3/18 2 ratio of 1 2) in canola oil. Canola oil has been found equally as effective as soybean oil, safflower oil, and sunflower oil in reducing plasma total and LDL cholesterol levels in normolipi-demic subjects. It also was effective in reducing plasma total and LDL cholesterol levels in hyperlipidemic subjects when it replaced saturated fat in their diets. Canola oil diets also have been shown to affect the fatty acid composition of blood... 

Onion Allium cepa) seeds contained about 23.6% crude fat. The seed oil was analyzed for its chemical composition. The onion seed oil contained 44.6% linoieic acid and 34.3% oleic acid (Table 6) (38). The total unsaturated fatty acids comprised of 79% of the oil. A greater concentration of linoieic acid was determined in the cold-pressed onion seed oil obtained from Botanical Oil Co. (Spooner, Wl). Linoieic acid accounted for 63.7% of total fatty acids, and oleic acid ranged from 26.7-30.1%. The total unsaturated fatty acids were about 90% (3). In summary, onion seed oil may serve as a dietary source of essential n-6 fatty acid and oleic acid. 

Dates Phoenix dactylifera L.) are popular in most Middle Eastern countries and serve as a major source of food and nutrients (51, 52). Oil contents and fatty acid profiles of date seeds may vary among individual varieties. Date seeds contained 20-24% total fat (49). Oleic acid was the primary fatty acid in the date seed oil and had a concentration of 43.5 5% of total fatty acids. This was followed by lauric (12 0), myristic (14 0), palmitic (16 0), linoleic (18 2n6), capric (10 0), and stearic (18 0) acids along with trace amounts of other fatty acids (Table 7). Date seed oil may serve as an excellent dietary source of oleic acid with a minor amount of linoleic acid. 

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