Given the wide-ranging importance and benefits of marine omega-3 fatty acids, it is important to eat fish or other seafood one to two times per week, particularly fatty dark meat fish that are richer in EPA and DHA. This is especially important for women who are pregnant or hoping to become pregnant and nursing mothers. From the third trimester until the second year of life, a developing child needs a steady supply of DHA to form the brain and other parts of the nervous system.
Many women shy away from eating fish because of concerns that mercury and other possible contaminants might harm their babies, 9 yet the evidence for harm from lack of omega-3 fats is far more consistent, and a balance of benefit vs. To learn more about the controversy over contaminants in fatty fish, read Fish: Friend or Foe.
Women who are or may become pregnant, nursing mothers, and young children should avoid these high-mercury species of fish, but can eat up to 12 ounces two average meals a week of a variety of fish and shellfish that are lower in mercury. Women who are or may become pregnant, nursing mothers, and young children should limit albacore tuna to one serving per week. Leaf A.
Prevention of sudden cardiac death by n-3 polyunsaturated fatty acids. J Cardiovasc Med. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial.
Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients JELIS : a randomised open-label, blinded endpoint analysis. Willett WC. The role of dietary n-6 fatty acids in the prevention of cardiovascular disease. Interplay between different polyunsaturated fatty acids and risk of coronary heart disease in men.
Dietary intake of n-3 and n-6 fatty acids and the risk of prostate cancer. Am J Clin Nutr. A prospective study of dietary alpha-linolenic acid and the risk of prostate cancer United States. The docosahexaenoic acid C is indispensable for the neuronal myelination, and it is an important precursor for the very long chain fatty acid synthesis C, C, C, C, C, C , found in the brain.
It is also involved in neurogenesis, neurotransmission and protects the brain from the oxidative stress. It has an important role in maintaining the integrity of the basal membrane and as a phospholipid ester maintains the flexibility of the cellular membrane, helping the synaptic transmission, and it can also adjust the speed of the signal transmission. DHA can influence the brain development because it can regulate the gene expression, monoaminergic neurotransmission or protection against apoptotic cell death [ 24 ].
During pregnancy, DHA accumulates in human neonatal brain tissue at an accelerated rate during the third trimester in association with rapid changes in cortical structural maturation. A deficit of this fatty acid in the stage of the brain development can lead to the cognitive performance alterations [ 24 ]. The polyunsaturated fatty acids, besides their role of maintaining the integrity of the neuronal cell membrane, are involved in the synthesis of eicosapentaenoic acid from which the synthesis of the 3-series prostaglandin and 5-leukotriene begins.
EPA has neuroprotective, anti-oxidant and anti-inflammatory properties [ 24 ]. In case of deficiency of DHA and EPA, the cell permeability modifies and mitochondrial dysfunctions and inflammation appear, and along with the oxidative stress, it plays an important role in the progression of the disease. DHA and EPA can play a role in alleviating oxidative stress and reducing the risk of neurodegenerative diseases [ 25 ]. The novel series of lipid mediators resolvins, protectins and maresins have revealed their protective and beneficial effect in neurological diseases, due to their anti-inflammatory and pro-resolving properties.
A simultaneous deficiency of LA and ALA creates serious problems in fatty acid composition of the brain. ALA deficiency alters the course of brain development and perturbed the composition of brain cell membranes, neurons, oligodendrocytes and astrocytes as well as subcellular components such as myelin, nerve endings and mitochondria. Several other neurological disorders present altered neuronal and plasma fatty acid composition, such as depression, bipolar disorder, schizophrenia and attention deficit hyperactivity disorder.
Depression is accompanied by activation of the inflammatory response system indicated by an increased production of inflammatory cytokines and oxidative biomarker. Cytokine production is accompanied by increased oxidative stress leading to elevated production of reactive oxygen species ROS and nitric oxide NO or decreased anti-oxidant defense, such as superoxide dismutase SOD and glutathione peroxidase.
Epidemiological studies also showed that low intake and blood levels of omega-3 PUFAs are associated with an increased risk for being diagnosed with major depressive disorder. Erythrocyte levels of C, C, EPA and the omega-3 index were significantly lower in the case of patients diagnosed with major depression than in the controls, whereas erythrocyte levels of C, Cn6, Cn3, Ct and Ct were significantly higher [ 26 ].
Different studies suggest that omega-3 fatty acid status influences the development of central serotonin systems. A deficit of the omega-3 fatty acids leads to impaired serotonin release and behavioral signs of depression and aggression. Patients with major depressive disorder present a DHA deficiency compared to healthy controls [ 27 ]. The patients diagnosed with bipolar disorder presented higher plasma concentrations of all saturated fatty acids than the controls.
In this disorder too, the most important differences between the two groups were represented by the significant decreases in DHA levels and strong increases in levels of EPA and ALA [ 28 ]. The presently available data of the literature suggest that the metabolism of PUFAs is altered in patients with schizophrenia, both in the acute and chronic stages of the disease.
Altered neuronal membrane structure and metabolism might contribute to some of the symptoms of schizophrenia. A change in membrane lipid composition in neuronal cells can affect neurotransmission and this way can affect the behavior in schizophrenia. Studies showed no difference between the schizophrenia patients and control subjects in the contribution of omega-3 fatty acids to the lipid composition of the phospholipid fraction.
However, the values of total omega-6 PUFAs and docosapentaenoic acid are shown to be significantly lower in case of patients with schizophrenia than in case of the control subjects. Membrane lipids seem to fluctuate in different disease phases. This may be related to changes in neuroinflammatory and oxidative processes, which are reported to contribute to disease progression and underlie symptom severity.
The healthy group presents stable PUFA levels compared to the patients group. PUFAs are not only important components of neuronal cell membranes but also play an important role in regulation of inflammation through the formation of eicosanoids. Inflammation and oxidative stress may play a role in disease progression through lipid peroxidation and cholesterol oxidation, leading to neuronal cell death [ 29 ]. PUFA deficiency will also impair dopaminergic and glutamatergic neurotransmission, which are linked to negative symptoms.
Inflammation plays a role in the etiology of many types of cancer. It was reported that high concentration of serum long-chain omega-3 fatty acid phospholipids, EPA and DHA, in particular, was associated with the increased risk of high-grade prostate cancer.
However, high concentrations of trans -fatty acids, which are known to produce inflammation, are associated with a reduced risk of prostate cancer [ 30 ]. Other studies have been realized on colorectal cancer tissues from which different fatty acids have been separated. The analysis revealed high concentrations of saturated fatty acids and low levels of monounsaturated fatty acids.
Likewise, the dysfunction of the lipid metabolism from the hepatocellular carcinoma can lead to an altered plasma lipid profile. The main differences were evidenced in case of Cn-6, Cn-6, C and Cn These fatty acids can be considered potential biomarkers in case of hepatocellular carcinoma [ 32 ].
Obesity is a metabolic disease, and it increases the risk to develop diabetes, non-alcoholic fatty liver disease or other cardiovascular diseases. Compared to healthy volunteers, plasma levels of fatty acids are increased in the obese patients. The biomarker identified in this disease is the increased level of the unsaturated fatty acids, especially the palmitoleic acid C and dihomo-gamma-linolenic acid C [ 33 ].
Besides obesity, the polycystic ovary syndrome PCOS can lead to insulin resistance. In this case, two biomarkers were identified: nervonic acid C for the presence of PCOS and dihomo-gamma-linolenic acid for insulin resistance [ 4 ]. This way the cell permeability and the inflammatory cell infiltration are increased. This may explain why arachidonic acid is considered a biomarker in the plasma of diabetic patients, with or without different stages of nephropathy.
The fatty acid profile is modified in case of an infectious disease, too. In the incipient stage of the dengue fever, a decreased level of C, C, C, Cn6 and Cn3 was observed [ 4 ]. The last one is a genetic disease in which the fatty acid profile is altered. The pathobiology of sickle cell disease is initiated by episodic vascular occlusion in which the adherence of circulating blood cells to vascular endothelium is modulated by polyunsaturated fatty acids.
Patients diagnosed with this disease have altered red cell and PUFA composition. This is characterized by an increased AA, decreased DHA and EPA levels, and this may play a role in abnormal blood-endothelial cell interactions [ 34 ]. Long chain fatty acids are found in a low concentration in plasma, being difficult to identify them. In the peroxisomal disorders, such as the Zellweger or the adrenoleukodystrophy, the very long chain fatty acids accumulate in the plasma, which leads to the intracellular calcium accumulation and decreases the mitochondrial respiration, which leads to the cellular death of the oligodendrocyte and astrocytes.
Important biomarkers in this disease are C, C and C [ 35 ]. The chronic obstructive pulmonary disease COPD is a chronic inflammatory disorder of the airways in which the airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath.
Asthma is thought to be caused by a combination of genetic and environmental factors. Once it is installed, the inflammation starts and involves various cell types and mediators. Smoking is one of the major risk factors for the development of COPD, although other risk factors, such as air pollution and genetic factors, exist. The C and the C were the most significantly decreased, whereas the monounsaturated fatty acid, C, was increased in COPD compared to non-smokers [ 36 ]. Many epidemiological studies showed the protective role of DHA in allergic diseases because it suppresses airway eosinophilic inflammation.
A new monoglyceride DHA derivative and EPA derivative showed their protective effects on airway inflammation and inflammatory cytokine production. Patients with severe asthma present a selective dysregulation of the lypooxigenase pathway, the reason why a 5-lipoxygenase-dependent metabolite of arachidonic acid, 5-HETE, was similar in patients and healthy subjects [ 37 ].
Table 1 summarizes the biological effects of the most important fatty acids. Summary table of biological effects of some FA and their implications in some pathologies.
A significant consumption of omega-3 PUFAs results in a decreased level of arachidonic acid in the membranes of inflammatory cells.
This will lead to a decreased level of pro-inflammatory eicosanoids. There is a large amount of literature based on studies investigating the effects of omega-3 PUFAs on inflammation and immune function.
The most studies are investigating the fish oil effect on human health. Many studies have been published on the effect of omega-3 PUFAs on brain structure and function. Most of them indicate an increased functional activation in children, although not all of them found any effect of omega-3 fatty acids on cognition [ 24 ]. In this way, especially omega-3 and omega-6 fatty acids become a common point to these pathologies, such as cardiovascular, neurologic, oncologic or endocrinologic diseases, due to their mechanism of action at a cellular level.
We have proved the protective effect of DHA and EPA on different types of tissues; however, other types of fatty acids are not to be ignored. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.
Help us write another book on this subject and reach those readers. Budget Friendly Meals. Cooking with Kids. One Pot Meals. Ekahi Ornish. Apply Online. Deli Menus. Super Saver Flyer. The Benefits of Essential Fatty Acids. Facebook Twitter Pinterest Print. These EFAs are necessary for the following processes: Formation of healthy cell membranes Proper development and functioning of the brain and nervous system Proper thyroid and adrenal activity Hormone production Regulation of blood pressure, liver function, immune and inflammatory responses Regulation of blood clotting: Omega-6 FAs encourage blood clot formation, whereas Omega-3 oil reduces clotting.
Sources of Omega-6 fatty acids include nuts, seeds, grains, legumes, and dairy. Health Topics Alternative Medicine. Childrens' Health.
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