For many persons who wish to obtain the health benefits provided by dietary n-3 fatty acids, daily ingestion of fish or fish oil is not a sustainable long-term approach. To increase the number of sustainable dietary options, a land-based source of n-3 fatty acids that is effective in increasing tissue concentrations of the long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is required.
The objective of the study was to examine the ability of dietary stearidonic acid (SDA) to increase tissue concentrations of EPA and DHA in healthy human subjects and to compare the effectiveness of SDA with that of the n-3 fatty acids alpha-linolenic acid (ALA) and EPA.
Encapsulated SDA, ALA, or EPA was ingested daily in doses of 0.75 g and then 1.5 g for periods of 3 wk each by healthy male and postmenopausal female subjects (n = 15/group) in a double-blind, parallel-group design.
Dietary SDA increased EPA and docosapentaenoic acid concentrations but not DHA concentrations in erythrocyte and in plasma phospholipids. The relative effectiveness of the tested dietary fatty acids in increasing tissue EPA was 1:0.3:0.07 for EPA:SDA:ALA.
Vegetable oils containing SDA could be a dietary source of n-3 fatty acids that would be more effective in increasing tissue EPA concentrations than are current ALA-containing vegetable oils. The use of SDA-containing oils in food manufacture could provide a wide range of dietary alternatives for increasing tissue EPA concentrations.
"So far no strong evidences have proved that ALA has direct effects on CHD . It has been clearly investigated that ALA converts to EPA and DHA to a low extent through desaturation and elongation reaction which is limited by Δ6 desaturase [12–14]. However, some previous studies reported ALA that contributed to meet demand of DHA accretion in vivo similar to DHA in the different tissue , and effect on hypolipidemia was relatively to increasing levels of EPA and DHA [16–18]. "
[Show abstract][Hide abstract] ABSTRACT: In order to evaluate the effects of extract by SCE (supercritical carbon dioxide extraction) from cole pollen on lipid metabolism in hyperlipidemic rats, the experimental hyperlipidemic rats were established by providing with high fat diets, and randomized into six groups. After four weeks of perfusion diets into stomach, the rats were executed, and lipid levels of serum and hepatic tissue were detected. The serum levels of TC and TG were significantly lower in the pollen extract groups and MC group than in HFC group. Hepatic TC levels were decreased in rats fed pollen extract and lovastatin compared with HFC group. A higher concentration of HDL-C and apoAI in hepatic tissue was measured after intake of the pollen extract compared to the HFC group (P < 0.05). LCAT activity in serum of pollen extract groups was significantly higher than that in HFC group, and also HMG-CoA reductase showed decreasing tendency in pollen extract groups. The contents of DHA in pollen extract groups were found higher than those in HFC group. Cole pollen extract enriched in alpha-linolenic acid is likely to be a novel source of ALA which is probably responsible for favorable lipid changes through promoting transportation, excretion, and metabolism of cholesterol in hepatic tissue and serum.
"Because SDA is readily converted into EPA and DHA upon consumption, it may potentially be used to increase blood levels of ω-3 PUFAs [10,11]. Indeed, ingestion of vegetable oils enriched in SDA has been shown to increase EPA concentrations in tissue , and Kawabata et al. demonstrated that increasing the consumption of SDA-containing soybean oil modifies the lipid and FA profiles in body fats. Becasue ω-6 PUFAs are not readily converted into ω-3 PUFAs, the ratio of ω-6 to ω-3 PUFAs is largely determined by dietary intake of FAs . "
[Show abstract][Hide abstract] ABSTRACT: Polyunsaturated fatty acids (PUFAs), which contain two or more double bonds in their backbone, are the focus of intensive global research, because of their nutritional value, medicinal applications, and potential use as biofuel. However, the ability to produce these economically important compounds is limited, because it is both expensive and technically challenging to separate omega-3 polyunsaturated fatty acids (omega-3 PUFAs) from natural oils. Although the biosynthetic pathways of some plant and microalgal omega-3 PUFAs have been deciphered, current understanding of the correlation between fatty acid desaturase content and fatty acid synthesis in Synechocystis sp. PCC6803 is incomplete.
We constructed a series of homologous vectors for the endogenous and exogenous expression of Delta6 and Delta15 fatty acid desaturases under the control of the photosynthesis psbA2 promoter in transgenic Synechocystis sp. PCC6803. We generated six homologous recombinants, harboring various fatty acid desaturase genes from Synechocystis sp. PCC6803, Gibberella fujikuroi and Mortierella alpina. These lines produced up to 8.9 mg/L of alpha-linolenic acid (ALA) and 4.1 mg/l of stearidonic acid (SDA), which are more than six times the corresponding wild-type levels, at 20[degree sign]C and 30[degree sign]C. Thus, transgenic expression of Delta6 and Delta15 fatty acid desaturases enhances the accumulation of specific omega-3 PUFAs in Synechocystis sp. PCC6803.
In the blue-green alga Synechocystis sp. PCC6803, overexpression of endogenous and exogenous genes encoding PUFA desaturases markedly increased accumulation of ALA and SDA and decreased accumulation of linoleic acid and gamma-linolenic acid. This study lays the foundation for increasing the fatty acid content of cyanobacteria and, ultimately, for producing nutritional and medicinal products with high levels of essential omega-3 PUFAs.
Biotechnology for Biofuels 03/2014; 7(1):32. DOI:10.1186/1754-6834-7-32 · 6.04 Impact Factor
"In view of the very limited bioconversion of alpha-linolenic acid (ALA, 18:3 n-3) to DHA, averaging 3.5% in adults, recent clinical trials have focused on the potential benefits of supplementation with preformed DHA. It is noted that the desaturation product of ALA is stearidonic acid (18:4 n-3), and it is now found in some genetically modified seeds and oils and gives a 3–4-fold greater rise in blood levels of eicosapentaenoic acid (EPA, 20:5 n-3) when compared with ALA (James et al. 2003) after a few weeks of daily feeding (without any increase in circulating DHA). Makrides et al. (2010) observed a significantly lower prevalence of preterm babies, low birth weight infants, and admission of newborns to intensive care by 52%, 36%, and 45%, respectively, when the pregnant mothers were supplemented with 800 mg of DHA (plus 100 mg of EPA) daily over 21 weeks of gestation compared with the placebo group. "
[Show abstract][Hide abstract] ABSTRACT: The science of lipid research continues to rapidly evolve and change. New knowledge enhances our understanding and perspectives on the role of lipids in health and nutrition. However, new knowledge also challenges currently held opinions. The following are the proceedings of the 2013 Canadian Nutrition Society Conference on the Advances in Dietary Fats and Nutrition. Content experts presented state-of-the-art information regarding our understanding of fish oil and plant-based n-3 polyunsaturated fatty acids, nutrigenomics, pediatrics, regulatory affairs, and trans fats. These important contributions aim to provide clarity on the latest advances and opinions regarding the role of different types of fats in health.
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