? - Linolenic acid ( ALA ) is a fatty acid n -3. This is one of the two essential fatty acids (the other linoleic acid), so called because they are necessary for health and can not be produced in the human body. They must be obtained through diet. ALA is an omega-3 fatty acid found in seeds (chia, flaxseed, hemp, see also table below), nuts (especially walnuts), and many common vegetable oils. In terms of its structure, it is named all - cis -9,12,15-octadecatrienoic acid. In physiological literature, it is listed by its lipid number, 18: 3, and ( n -3); the GLA isomer is 18: 3 ( n -6).
? -Linolenic acid is a carboxylic acid with 18-carbon chain and three double bonds cis . The first double bond lies in the third carbon from the methyl tip of the fatty acid chain, known as the tip of n . Thus,? -linolenic acid is double polyunsaturated fatty acids n -3 (omega-3). This is gamma-linolenic acid (GLA) isomer, double polyunsaturated fatty acids n -6 (omega-6).
Video Alpha-Linolenic acid
Histori
? -Linolenic acid was first isolated by Rollett as cited in J. W. McCutcheon synthesis in 1942, and refers to the 1930s Green and Hilditch survey. It was first synthesized in 1995 from a C6 homologous agent. The Wittig reaction of the phosphonium salt of [( Z-Z ) -nona-3,6-dien-1-yl] triphenylphosphonium bromide with methyl 9-oxononanoate, followed by saponification, completes the synthesis.
Maps Alpha-Linolenic acid
Food source
Seed oil is the richest source of the -linolenic acid, mainly from chia, perilla, flaxseed (rapeseed), rapeseed (canola), and soybean. ? -Linolenic acid is also obtained from the thylakoid membrane in the leaf Pisum sativum (peanut leaf). Chloroplast plants consisting of more than 95 percent of photosynthetic thylakoid membranes are highly liquid due to the large abundance of linolenic acid, which emerges as a sharp resonance in the high-resolution 13-NMR carbon spectrum, always. Some studies suggest that ALA remains stable during processing and cooking. However, other studies suggest that ALA may not be suitable for baking, as it will polymerize by itself, a feature that is exploited in paints with transition metal catalysts. Some ALAs can also oxidize at combustion temperatures. The percentage of ALA in the table below refers to the oil extracted from each item.
Potential role in nutrition and health
Although the best source of ALA is seed, most of the seeds and seed oils are much richer in <6> -6 fatty acids, linoleic acid. Exceptions include flaxseed (must be ground for proper nutrient absorption) and chia seeds. Linoleic acid is another essential fatty acid, but, and the other n -6 fatty acids, competes with n -3s for position in the cell membrane and has a very different effect. on human health. There is a complex set of essential fatty acid interactions.
? -Linolenic acid can only be obtained by humans through their diet because the absence of the necessary 12-and 15-desaturase enzymes makes the synthesis of de novo from stearic acid to be impossible. Eicosapentaenoic acid (EPA: 20: 5, n -3) and docosahexaenoic acid (DHA: 22: 6, n -3) are available from fish and algae oil and plays an important role in many metabolic processes. It can also be synthesized by humans from the -linolenic-acid diet, but with an efficiency of only a few percent. Because the efficacy of long-chain long-chain unsaturated fatty acids (LC-PUFA) declines down the cascade of linolenic-acid conversion, the synthesis of DHA from the -linolenic acid is even more limited than that of the EPA. The conversion of ALA to DHA is higher in women than in men.
Several studies have shown an association between -linolenic acid and an increased risk of prostate cancer. This risk is found regardless of origin source (eg, meat, vegetable oil). However, a large study of 2006 found no association between total intake of -linolenic acid and overall risk of prostate cancer; and meta-analysis 2009 found evidence of publication bias in previous studies, and concluded that if ALA contributes to an increased risk of prostate cancer, the increased risk is quite small.
Stability and hydrogenation
? -Linolenic acid is relatively more susceptible to oxidation and will become rancid faster than many other oils. The oxidative instability of the -linolenic acid is one of the reasons why producers choose to hydrogenate some of the oils containing the -linolenic acid, such as soybean oil. Soy is the largest source of vegetable oil in the US, and 40% of partially hydrogenated soybean oil production.
However, when partially hydrogenated, part of unsaturated fatty acids become unhealthy trans fats. Consumers increasingly avoid products containing trans fats, and the government has started banning trans fats in food products. These market regulations and pressures have spurred the development of low-linolenic acid soybeans. This new soybean variety produces a more stable oil that does not require hydrogenation for many applications, thus providing trans fat free products, such as cooking oil.
Some consortium bring low-linolenic acid soy to market. DuPont effort involves silencing the FAD2 gene that encodes? 6 -desaturase, providing soybean oil with very low levels of both? -linolenic acid and linoleic acid. The Monsanto Company has introduced to the Vistive market, their low -linolene soya acid brand, which is less controversial than GMO offerings, as it is made through conventional breeding techniques.
Cardiovascular
There is some evidence of ALA consumption may have little precautionary effect on cardiovascular disease.
See also
- Drain oil
- Essential fatty acids
- List n -3 fatty acids
- Essential nutrients
- Wheat wheat oil
References
Source of the article : Wikipedia
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