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PubMed1997

Essential fatty acid deficiency in patients with severe fat malabsorption.

Essential fatty acid deficiency is commonly described in patients receiving parenteral nutrition, but the occurrence in patients with severe fat malabsorption not receiving parenteral nutrition is uncertain. One hundred twelve patients were grouped according to their degree of fat malabsorption: group 1, < 10% (n = 52); group 2, 10-25% (n = 21); group 3, 25-50% (n = 24); and group 4, > 50% (n = 15). Fecal fat was measured by the method of Van de Kamer the last 2 of 5 d of a 75-g fat diet. Serum fatty acids in the phospholipid fraction were measured by gas-liquid chromatography after separation by thin-layer chromatography and expressed as a percentage of total fatty acids. The concentration of linoleic acid in groups 1, 2, 3, and 4 was 21.7%, 19.4%, 16.4%, and 13.4% respectively (P < 0.001). The concentration of linolenic acid in groups 1, 2, 3, and 4 was 0.4%, 0.4%, 0.3% and 0.3%, respectively (P = 0.017). Evidence of essential fatty acid deficiency, defined as a serum concentration of linoleic acid less than the lower limit if the 95% CI in patients without fat malabsorption (group 1), was 5% (1/21), 38% (9/24), and 67% (10/15) in groups 2, 3, and 4, respectively. A considerable proportion of patients with gastrointestinal diseases resulting in malabsorption of > 25-50% of dietary fat intake and not treated with parenteral nutrition have biochemical signs of essential fatty acid deficiency. The clinical effect of these changes are yet to be elucidated.

Adult↗
PubMed1984

[Microorganisms as potential producers of essential fatty acids].

The data on the importance of essential fatty acids in a balanced diet have been considered. The ways of essential fatty acid synthesis in microorganisms and their metabolism in animal tissues are being discussed. The criteria for microorganisms selection--producers of food lipids have been proposed.

Animal Nutritional Physiological Phenomena↗
PubMed1990

Postnatal ontogeny of gamma glutamyltranspeptidase activity of pancreas in essential fatty acid deficient rats treated with nitrosomethylurea.

The effect of essential fatty acid deficiency and nitrosomethylurea treatment on postnatal levels of pancreatic gamma-glutamyltranspeptidase was studied. A significant increase of gamma-glutamyltranspeptidase activity and changes in fatty acid composition were observed in essential fatty acid deficient rats, from the 14th day of life on. Pancreatic gamma-glutamyltranspeptidase of nitrosomethylurea injected rats in essential fatty acid deficiency and controls was significantly diminished at the 30th day, with no significant differences in both nutritional conditions. The results indicated: 1. Concomitant changes in gamma-glutamyltranspeptidase activity and fatty acid composition of rat pancreas in essential fatty acid deficiency, 2. A significant reduction of pancreatic gamma-glutamyltranspeptidase activity following a single intraperitoneal injection of nitrosomethylurea at day one of life and 3. No interacting effects of essential fatty acid deficiency and nitrosomethylurea on gamma-glutamyltranspeptidase activity of rat pancreas.

Animals↗
PubMed2001

Essential fatty acids in visual and brain development.

Essential fatty acids are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LC-PUFA). These fatty acids serve as specific precursors for eicosanoids, which regulate numerous cell and organ functions. Recent human studies support the essential nature of n-3 fatty acids in addition to the well-established role of n-6 essential fatty acids in humans, particularly in early life. The main findings are that light sensitivity of retinal rod photoreceptors is significantly reduced in newborns with n-3 fatty acid deficiency, and that docosahexaenoic acid (DHA) significantly enhances visual acuity maturation and cognitive functions. DHA is a conditionally essential nutrient for adequate neurodevelopment in humans. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oil sources of LC-PUFA results in increased blood levels of DHA and arachidonic acid, as well as an associated improvement in visual function in formula-fed infants matching that of human breast-fed infants. The effect is mediated not only by the known effects on membrane biophysical properties, neurotransmitter content, and the corresponding electrophysiological correlates but also by a modulating gene expression of the developing retina and brain. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation and retinal and nervous system development. Regulation of gene expression by LC-PUFA occurs at the transcriptional level and may be mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the family of steroid hormone receptors. DHA also has significant effects on photoreceptor membranes and neurotransmitters involved in the signal transduction process; rhodopsin activation, rod and cone development, neuronal dendritic connectivity, and functional maturation of the central nervous system.

Brain↗
PubMed2002

Long-chain polyunsaturated fatty acids in rat maternal milk, offspring brain and peripheral tissues in essential fatty acid deficiency.

Fatty acid status in humans is usually related to plasma or red blood cell fatty acid profiles. The aim of the study was to explore whether a maternal deficiency in dietary essential fatty acids would differentially affect lipid fractions in several tissues of the offspring, including brain. Female Wistar rats were fed an essential fatty acid-deficient diet during 3 months before mating. The fatty acid composition of different lipid fractions was examined in maternal milk, and in plasma, red blood cells, liver, adipose tissue, cerebral cortex and hippocampus of the offspring using thin layer and capillary column gas chromatography. Lipid fractions from most tissues of deprived offspring showed a common fatty acid profile characterized by elevated 20:3 omega9/20:4 omega6 ratio, and decreased docosahexaenoic acid and arachidonic acid. However, arachidonic acid was not affected in brain, even though 22:5 omega6 was increased in phospholipids of cerebral cortex and hippocampus. The present results demonstrate different degrees of resistance to essential fatty acid deficiency in lipid fractions and tissues. This suggests a priority distribution of arachidonic acid to preferential areas and shows that blood phospholipid fatty acids do not exactly reflect brain phospholipid status.

Adipose Tissue↗
PubMed1998

[Rapid determination of essential fatty acids of edible oils by conversion to their hydroxamic acids].

A simple and rapid HPLC method for the determination of essential fatty acids of edible oils was established. Oil samples were converted to their hydroxamic acids in a single step and analyzed without prior separation and purification. The chromatographic conditions were: Shim-pack CLC ODS, 5 microns, 150 mm x 6.0 mm i.d. column, 40 degrees C; MeOH: 0.02 mol/L NaH2PO4(pH 3.0) (81:19, V/V) as eluent and UV-213 nm detector. The linear range was 0.05-0.6 g/L, recovery was 96.93% and RSD was 1.80%(n = 4). The relative standard deviations for intra-day and inter-day assays were 1.24% and 1.62% respectively (n = 6). For 18:3, 18:2, 18:1, the difference between the derivatization yields from triglycerides and their methyl esters was almost one fold. That was confirmed by our recovery and determination results. The calibration curves for the oil samples should not be obtained from the derivatization of their methyl ester standards.

Chromatography, High Pressure Liquid↗
PubMed1976

Ultrastructural changes of the luminal plasma membrane of the transitional epithelium of the rat urinary tract in essential fatty acid deficiency.

Rats fed an essential fatty acid deficient diet (EFAD) showed a statistically significant decrease in the thickness and ultrastructural asymmetry of the luminal membrane and cytoplasmic vesicles of transitional epithelium of the urinary tract, due to a marked thinning of the peculiar thick luminal leaflet. These changes were reversed by adding EFA to the diet. This indicates that the unusual EM appearance of urothelial membrane depends on its content in EFA.

Animals↗
PubMed1987

Adenylate cyclase activity, membrane fluidity and fatty acid composition of rat heart in essential fatty acid deficiency.

Three groups of male, weanling, Sprague-Dawley rats were fed diets containing 7% hydrogenated coconut oil, 6.6% hydrogenated coconut oil + 0.4% corn oil, or 7% corn oil for 8-17 weeks. These diets provided 0% (EFAD group), 0.5% (MEFAD group) or 5% (CONTROL group) of the total energy as linoleic acid, respectively. Crude plasma membranes were prepared from heart and assayed for adenylate cyclase activity. Both basal and fluoride-stimulated activity was lower in the membranes from EFAD and MEFAD rats than that of the controls. The double bond index of total lipids and phospholipids, and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were not appreciably different in the membranes from the three dietary groups. The fatty acid composition of total phospholipids of the membranes, however, was quite different and indicative of biochemical changes typical of an EFA deficiency. Feeding of the control diet to the EFAD or MEFAD rats for up to 6 weeks did not alleviate completely the changes in adenylate cyclase activity although the fatty acid patterns were restored to the normal levels. There was also a decrease in the number of [3H]-DHA binding sites in heart of EFAD rats as compared with their controls. The results suggest that the changes induced by EFA deficiency in the acyl group composition of membrane phospholipids and in the number of beta-adrenergic receptors may be important in regulating adenylate cyclase activity in the heart.

Adenylyl Cyclases↗
PubMed1999

Essential fatty acids, lipid peroxidation and apoptosis.

Essential fatty acids (EFAs) and their metabolites, especially gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid and decosahexaenoic acid are known to induce apoptotic death of tumour cells. But the exact mechanism by which these fatty acids are able to induce apoptosis is not clear. Recent studies suggest that these fatty acids are able to induce apoptosis in cells over expressing cytochrome P450 following depletion of cellular glutathione and inhibition of carnitine palmitoyl transferase I (CPTI) activity. On the other hand, BCL-2 prevented apoptosis induced by these long-chain fatty acids, where as n-3 fatty acids suppressed ras expression leading to suppression of development of overt neoplasia. Phosphorylation of BCL-2 inhibits its ability to interfere with apoptosis and enhances lipid peroxidation leading to the occurrence of apoptosis. Tumour cells treated with long-chain fatty acids show increase in lipid peroxidation process, depletion of antioxidants and phosphorylation of proteins. Based on these results, it is suggested that long-chain fatty acids induce apoptosis by enhancing lipid peroxidation, suppressing BCL-2 expression possibly by phosphorylation and augmentation of P450 activity. Thus, these long-chain fatty acids may, infact act at the level of gene/oncogene expression in producing their cytotoxic action on tumour cells.

Animals↗
PubMed2000

The deltaF508 mutation in the cystic fibrosis transmembrane conductance regulator alters control of essential fatty acid utilization in epithelial cells.

Essential fatty acid (EFA) incorporation into phospholipid is influenced by chloride channels, suggesting that the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) may regulate aspects of EFA metabolism. The objective of this study was to determine whether the DeltaF508 mutation in the CFTR lowers 18:2(n-6) levels in phospholipid. Control cells, CF cells and CF cells transfected with the "normal" CFTR gene or the DeltaF508 CFTR gene were cultured for 3-5 d and used to determine [1-(14)C]18:2(n-6) incorporation into cell lipids. CF cells exhibited low 18:2(n-6) levels in phospholipid, reduced [1-(14)C]18:2(n-6) incorporation into phospholipid (50% of control) and greater [1-(14)C]18:2(n-6) incorporation into the triacylglycerol fraction (400% of control; P: < 0.05). Kinetic modeling of time course data for [1-(14)C]18:2(n-6) incorporation revealed a loss of metabolic control over the intracellular partitioning of 18:2(n-6) between phospholipid and triacylglycerol pools in CF cells. Expression of the normal CFTR gene in transfected CF cells increased chloride efflux and the incorporation of [1-(14)C]18:2(n-6) into phospholipid and triacylglycerol fractions. The increased incorporation of [1-(14)C]18:2(n-6) into phospholipid was attributed to significantly increased incorporation of [1-(14)C]18:2(n-6) into phosphatidylcholine and phosphatidylinositol. In CF cells expressing the defective DeltaF508 CFTR gene, conversion of [1-(14)C]18:2(n-6) to 20:4(n-6) by desaturation-chain elongation was 1.8-fold greater (P: < 0.05) than observed for CF cells transfected with the normal gene. The observations suggest that CF results in a defect in the utilization of 18:2(n-6), which is attributed in part to the defective CFTR.

Cells, Cultured↗
PubMed1998

Regulation of cell adhesion, a central mechanism in the anticancer action of essential fatty acids (review).

Certain members of essential fatty acids (EFAs) are known to have anticancer functions. It has been established in recent years that some of these anticancer actions are via the effects of these fatty acids on the adhesive properties of cancer cells, including cell-cell and cell-matrix adhesions. These discoveries have implicated EFAs as a group of novel agents, able to regulate adhesive function of cancer cells and thus bearing clinical importance.

Animals↗
PubMed1999

Essential fatty acids in health and disease.

Essential fatty acids (EFAs) form an important component of cell membranes, are eicosanoid precursors and are therefore required for both the structure and function of every cell in the body. EFAs can modulate the activity of protein kinase C, T and B cell response, free radical generation and lipid peroxidation, lymphokine secretion and cell proliferation. EFAs also have anti-mutagenic, anti-bacterial, anti-fungal and anti-viral properties. EFAs and their metabolites lower serum cholesterol, triglycerides and blood pressure. EFAs appear to be of benefit in atopic eczema, premenstrual syndrome, psoriasis, auto-immune disorders especially rheumatoid arthritis and systemic lupus erythematosus, prevention of target organ damage in diabetes mellitus, peptic ulcer disease, ulcerative colitis, coronary heart disease and atherosclerosis. EFAs and their metabolites can selectively kill tumor cells both in vitro and in vivo without harming normal cells. In addition, EFAs seem to play a fundamental role in inflammation and immune response. In view of their actions and relative safety, it is anticipated that EFAs may be useful in the management of several diseases.

Cell Membrane↗
PubMed2005

Essential fatty acids, DHA and human brain.

Essential fatty acids cannot be synthesized in the body but they are required for maintenance of optimal health. There are two classes of polyunsaturated fatty acids (PUFAs)--omega-6 and omega-3. The parent omega-6 fatty acid, linoleic acid (LA) is desaturated in the body to form arachidonic acid while parent omega-3 fatty acid alpha-linolenic acid (ALA) is desaturated by microsomal enzyme system through a series of metabolic steps to form eicosapentaenoic acid (EPA) and decosahexaenoic acid (DHA). But there is a limited metabolic capability during early life to metabolize PUFAs to more active long-chain fatty acids. There is a critical role of EFAs and their metabolic products for maintenance of structural and functional integrity of central nervous system and retina. Most of the brain growth is completed by 5-6 years of age. At birth brain weight is 70% of an adult, 15% brain growth occurs during infancy and remaining brain growth is completed during preschool years. DHA is the predominant structural fatty acid in the central nervous system and retina and its availability is crucial for brain development. It is recommended that the pregnant and nursing woman should take at least 2.6 g of omega-3 fatty acids and 100-300 mg of DHA daily to look after the needs of her fetus and suckling infant. The follow-up studies have shown that infants of mothers supplemented with EFAs and DHA had higher mental processing scores, psychomotor development, eye-hand coordination and stereo acuity at 4 years of age. Intake of EFAs and DHA during preschool years may also have a beneficial role in the prevention of attention deficit hyperactivity disorder (ADHD) and enhancing learning capability and academic performance.

Brain↗
PubMed1985

Paradoxical conservation of cardiac and renal arachidonate content in essential fatty acid deficiency.

The effects of essential fatty acid (EFA) deprivation on the arachidonate content and phospholipid composition of different tissues are quite diverse. When C57B1 mice were placed on a fat-free diet, hepatic liquids were readily depleted of arachidonate. In contrast, the renal cortex tenaciously retained arachidonate, whereas surprisingly the heart showed a doubling of its content of arachidonate. This increase in cardiac arachidonate was due to a four-fold increase in arachidonylphosphatidylethanolamine (PE). The renal cortex showed preservation of its arachidonate content in PE, phosphatidylserine, and phosphatidylcholine. Only phosphatidylinositol was depleted of arachidonate in heart or renal cortex. Using an in vivo labeling technique, it was shown that the liver incorporated most of the [1-14C]arachidonate initially following intraperitoneal injection. Over 11 days, as levels of labeled arachidonate fell in liver, the EFA-deficient heart accumulated arachidonate selectively in PE (8-fold greater than control), and the EFA-deficient renal cortex accumulated arachidonate in PE, phosphatidylserine, and phosphatidylcholine (2-3-fold greater than control). This uptake was shown to be specific for arachidonate over 20:3(n-9). Despite the conservation of cardiac and renal arachidonate seen with EFA deficiency, prostaglandin production by the isolated perfused EFA-deficient heart and kidney was markedly decreased relative to control in response to specific agonist stimulation with angiotensin II, although it was equivalent to control in response to nonspecific stimulation by ischemia. These data suggest that the liver serves to supply other tissues with arachidonate in EFA deficiency, and that the heart and renal cortex both contain mechanisms to accumulate arachidonate selectively in certain phospholipids. However, phosphatidylinositol, which is uniquely depleted of arachidonate in heart and renal cortex with EFA deficiency, appears to be the principal source of arachidonate in response to receptor-mediated agonists.

Animals↗
PubMed1986

Retinal function in rats and guinea-pigs reared on diets low in essential fatty acids and supplemented with linoleic or linolenic acids.

Rats were reared into a third generation on diets deficient in essential fatty acids supplemented with linoleic acid (18:2 n-6) or linolenic acid (18:3 n-3) with the object of depleting the retina of n-6 or n-3 fatty acids. In the rats fed 18:2 n-6 the percentage by weight of 22:6 n-3 in retinal fatty acids fell from 22.5 to 8.5% in first-generation animals but then remained unchanged in second and third generations. There was no difference in b-wave amplitudes of the electroretinogram between the rats fed 18:2 n-6 and those fed 18:3 n-3. In guinea-pigs fed purified diets low in 18:3 n-3 the percentage by weight of 22:6 n-3 in retinas fell from 8 to less than 0.5% by the third generation. However, there were no statistical differences in the b-wave amplitudes between these animals and those reared on a commercial diet. It is concluded that if n-3 fatty acids are involved in retinal function their role is too subtle to be detected by standard electroretinographic techniques.

Aging↗
PubMed1987

[Essential fatty acids in parenteral nutrition].

Fat is a very important nutrient in that it supplies energy, essential fatty acids and fat soluble vitamins. The importance of n-6 essential fatty acids, i.e., linoleic and arachidonic acid, in total parenteral nutrition was demonstrated in the last 15 years by several cases of essential fatty acid deficiency. In addition, n-3 fatty acids, i.e., alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid, are essential nutrients in forming an independent family of eicosanoids with biological effects different from those of the n-6 fatty acids. The requirement of different essential fatty acids in patients with total parenteral nutrition after heavy injury is of special interest with respect to the development and prognosis of shock, sepsis or adult respiratory distress syndrome. The available soy oil based fat emulsions contain n-6 and n-3 fatty acids in a suitable proportion of 7:1, but further information on essential fatty acid requirement in different diseases is necessary.

Fat Emulsions, Intravenous↗
PubMed1988

Effects of essential fatty acids on mild to moderate essential hypertension.

A double-blind placebo-controlled study with a crossover design was conducted on 25 non-obese black patients with mild-moderate uncomplicated essential hypertension. They were randomly assigned into two groups. After having received placebo capsules for 4 weeks, they received dietary supplementation with either Efamol-marine (containing desaturated n-6 and n3 essential fatty acids), or sunflower seed and linseed oil capsules for 12 weeks. Thereafter a second 4 weeks placebo phase and a subsequent second 12-week active phase were entered into during which a crossover of the dietary supplementation of the groups was brought about. The mean systolic blood pressure of patients receiving Efamol-marine was significantly lowered after 8 and 12 weeks, while those receiving sunflower/linseed oil supplementation had no significant reduction of blood pressure. This observation may indicate that defective desaturation of the essential fatty acids by the enzyme delta-6-desaturase, could play an important role in the etiology of essential hypertension.

Adult↗