Docosahexaenoic acid

About: Docosahexaenoic acid is a research topic. Over the lifetime, 14412 publications have been published within this topic receiving 620852 citations. The topic is also known as: all-cis-DHA & all-cis-docosa-4,7,10,13,16,19-hexaenoic acid.

Omega-3 Fatty Acids and Pregnancy

Abstract: Omega-3 fatty acids are essential fatty acids that must be consumed in the diet. Adequate consumption of omega-3 fatty acids is vitally important during pregnancy as they are critical building blocks of fetal brain and retina. Omega-3 fatty acids may also play a role in determining the length of gestation and in preventing perinatal depression. The most biologically active forms of omega-3 fatty acids are docosahexaenoic acid and eicosapentaenoic acid, which are primarily derived from marine sources such as seafood and algae. Recent surveys, however, indicate that pregnant women in the United States and in other countries eat little fish and therefore do not consume enough omega-3 fatty acids, primarily due to concern about the adverse effects of mercury and other contaminants on the developing fetus. This review discusses the benefits of omega-3 fatty acid consumption during pregnancy and provides guidelines for obstetricians advising patients.

Relationship between vitamin E requirement and polyunsaturated fatty acid intake in man: a review.

Abstract: Vitamin E is the general term for all tocopherols and tocotrienols, of which alpha-tocopherol is the natural and biologically most active form. Although gamma-tocopherol makes a significant contribution to the vitamin E CONTENT in foods, it is less effective in animal and human tissues, where alpha-tocopherol is the most effective chain-breaking lipid-soluble antioxidant. The antioxidant function of vitamin E is critical for the prevention of oxidation of tissue PUFA. Animal experiments have shown that increasing the degree of dietary fatty acid unsaturation increases the peroxidizability of the lipids and reduces the time required to develop symptoms of vitamin E deficiency. From these experiments, relative amounts of vitamin E required to protect the various fatty acids from being peroxidized, could be estimated. Since systematic studies on the vitamin E requirement in relation to PUFA consumption have not been performed in man, recommendations for vitamin E intake are based on animal experiments and human food intake data. An intake of 0.6 mg alpha-tocopherol equivalents per gram linoleic acid is generally seen as adequate for human adults. The minimum vitamin E requirement at consumption of fatty acids with a higher degree of unsaturation can be calculated by a formula, which takes into account the peroxidizability of unsaturated fatty acids and is based on the results of animal experiments. There are, however, no clear data on the vitamin E requirement of humans consuming the more unsaturated fatty acids as for instance EPA (20:5, n-3) and DHA (22:6, n-3). Studies investigating the effects of EPA and DHA supplementation have shown an increase in lipid peroxidation, although amounts of vitamin E were present that are considered adequate in relation to the calculated oxidative potential of these fatty acids. Furthermore, a calculation of the vitamin E requirement, using recent nutritional intake data, shows that a reduction in total fat intake with a concomitant increase in PUFA consumption, including EPA and DHA, will result in an increased amount of vitamin E required. In addition, the methods used in previous studies investigating vitamin E requirement and PUFA consumption (for instance erythrocyte hemolysis), and the techniques used to assess lipid peroxidation (e.g. MDA analysis), may be unsuitable to establish a quantitative relation between vitamin E intake and consumption of highly unsaturated fatty acids. Therefore, further studies are required to establish the vitamin E requirement when the intake of longer-chain, more-unsaturated fatty acids is increased. For this purpose it is necessary to use functional techniques based on the measurement of lipid peroxidation in vivo. Until these data are available, the widely used ratio of at least 0.6 mg alpha-TE/g PUFA is suggested. Higher levels may be necessary, however, for fats that are rich in fatty acids containing more than two double bonds.

Reduced Red Blood Cell Membrane Essential Polyunsaturated Fatty Acids in First Episode Schizophrenia at Neuroleptic-Naive Baseline

Abstract: There is emerging evidence in schizophrenia of membrane abnormalities, primarily reductions in the essential omega-3 and omega-6 series of polyunsaturated fatty acids (PUFA). Because previous studies have largely been in chronic patients, it is not known whether these membrane abnormalities also occur early in illness. In the present study, red blood cell membrane fatty acid levels were determined by capillary gas chromatography from 24 neuroleptic-naive patients with first episode schizophrenia or schizoaffective disorder and 31 age-matched normal controls. Relative to normal subjects, patients had significant reductions in total PUFA (-13%) but not in monounsaturated or saturated fatty acids. Specifically, significant reductions were found in arachidonic acid (-18%), docosapentaenoic acid (-36%), and docosahexaenoic acid (-26%) concentrations. These reductions were not related to age, gender, smoking status, or cotinine levels. These results confirm previous findings of membrane deficits in schizophrenia and show that significant PUFA reductions occur early in the illness, prior to initiation of treatment, raising the possibility that these deficits are trait related. The findings also suggest that membrane fatty acid losses are quite specific to the highly unsaturated fatty acids.

Omega‐3 fatty acids in wild plants, nuts and seeds

Abstract: inflammatory, antithrombotic, anti-arrhythmic, hypolipidemic, and vasodilatory properties. These beneficial effects of omega-3 fatty acids have been shown in the secondary prevention of coronary heart disease and hypertension, as for example, in the Lyon Heart Study, the GISSI Prevenzione Trial, and in the The Dietary Approaches to Stop Hypertension Study. Most of the studies have been carried out with fish oils (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)). However, α-linolenic acid (ALA), found in green leafy vegetables, flaxseed, rapeseed, and walnuts, desaturates and elongates in the body to EPA and DHA and by itself may have beneficial effects in health and in the control of chronic diseases. The present paper identifies multiple sources of ALA from plants, legumes, nuts and seeds and emphasizes the importance of the ratio of omega-6 to omega-3 fatty acids for proper desaturation and elongation of ALA into EPA and DHA. α-linolenic acid is not equivalent in its biological effects to the long-chain omega-3 fatty acids found in marine oils. Eicosapentaenoic acid and DHA are more rapidly incorporated into plasma and membrane lipids and produce more rapid effects than does ALA. Relatively large reserves of linoleic acid in body fat, as are found in vegans or in the diet of omnivores in Western societies, would tend to slow down the formation of long-chain omega-3 fatty acids from ALA. Therefore, the role of ALA in human nutrition becomes important in terms of long-term dietary intake. One advantage of the consumption of ALA over omega-3 fatty acids from fish is that the problem of insufficient vitamin E intake does not exist with high intake of ALA from plant sources.

Disturbed Choline Plasmalogen and Phospholipid Fatty Acid Concentrations in Alzheimer's Disease Prefrontal Cortex

Abstract: Alzheimer disease (AD) is a progressive neurodegenerative disorder characterized by brain deposition of senile (neuritic) plaques containing β-amyloid, neurofibrillary tangles, synaptic loss, neuroinflammation, and overexpression of arachidonic acid (AA, 20:4n-6) metabolizing enzymes. Lipid concentration changes have been reported in different brain regions, but often partially and/or as a percent of the total concentration. In this study, we measured absolute concentrations (per gram wet weight) of a wide range of lipids in postmortem prefrontal cortex (Brodmann area 9) from 10 AD patients and 9 controls. Mean total brain lipid, phospholipid, cholesterol and triglyceride concentrations did not differ significantly between AD and controls. There was a significant 73% decrease in plasmalogen choline, but no difference in other measured phospholipids. Fatty acid concentrations in total phospholipid did not differ from control. However, docosahexaenoic acid (DHA, 22:6n-3) was reduced in ethanolamine glycerophospholipid and choline glycerophospholipid, but increased in phosphatidylinositol. AA was reduced in choline glycerophospholipid, but increased in phosphatidylinositol, while docosatetraenoic acid (22:4n-6), an AA elongation product, was reduced in total brain lipid, cholesteryl ester and triglyceride. These lipid changes may contribute to membrane instability and synaptic loss in AD, and reflect neuroinflammation and excitotoxicity.