The Effects of Omega‐3 Polyunsaturated Fatty Acid Consumption on Mammary Carcinogenesis

The consumption of omega‐3 polyunsaturated fatty acids (n‐3 PUFA) is associated with a reduced risk of breast cancer. Studies in animals and in vitro have demonstrated mechanisms that could explain this apparent effect, but clinical and epidemiological studies have returned conflicting results on the practical benefits of dietary n‐3 PUFA for prevention of breast cancer. Effects are often only significant within a population when comparing the highest n‐3 PUFA consumption group to the lowest n‐3 group or highest n‐6 group. The beneficial effects of n‐3 PUFA eicosapentaenoic and docosahexaenoic on the risk of breast cancer are dose dependent and are negatively affected by total n‐6 consumption. The majority of the world population, including the most highly developed regions, consumes insufficient n‐3 PUFA to significantly reduce breast cancer risk. This review discusses the physiological and dietary context in which reduction of breast cancer risk may occur, some proposed mechanisms of action and meaningful recommendations for consumption of n‐3 PUFA in the diet of developed regions.     

Effects of n‐3 PUFA on insulin resistance after an oral fat load

The aim of this study was to evaluate the effects of ω‐3 PUFA (n‐3 PUFA) on lipid profile and insulin resistance biomarkers. Patients were assigned to receive placebo or n‐3 PUFA 1 g three times a day, during the meals, for 6 months. We evaluated: body mass index (BMI), body weight, fasting plasma glucose (FPG), fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index (HOMA‐IR), blood pressure, lipid profile, resistin (r), retinol binding protein‐4 (RBP‐4), adiponectin (ADN), visfatin, and vaspin. Furthermore patients underwent an oral fat load (OFL) and an euglycemic hyperinsulinemic clamp to evaluate M value, and total glucose requirement (TGR). Triglycerides value obtained with n‐3 PUFA was lower, while HDL‐C, and ADN values were higher compared to placebo. After the OFL, and comparing the OFL performed at the baseline and at the end of the study, there was a decrease of triglycerides (Tg), resistin (r), and RBP‐4 values, and an increase of ADN value with n‐3 PUFA, but not with placebo. We conclude that the treatment with n‐3 PUFA resulted in a greater improvement of lipid profile and ADN compared to placebo in a baseline condition, and an improvement of all insulin resistance parameters after an OFL. Practical applications: The inverse association between dietary intake of n‐3 PUFA and cardiovascular disease morbidity/mortality was primarily established following the observation that the Greenland Inuits had low mortality from coronary heart disease despite a fat‐rich diet. Our group has already shown that n‐3 PUFA improved the lipid profile and the coagulation, fibrinolytic, and inflammatory parameters compared to placebo. We also observed that highly purified n‐3 PUFA supplementation significantly reduced the blood pressure, pulse pressure, and basal heart rate in hypertriglyceridemic patients with normal‐high blood pressure. The current study showed that treatment with n‐3 PUFA not only improved lipid profile in a baseline situation, but it also improved all insulin resistance parameters in a post‐prandial situation simulated with an OFL. This is another important action of the n‐3 PUFA which can increase their utility in the clinical practice.     

Intestinal digestion of fish oils and ω‐3 concentrates under in vitro conditions

A comparative study of the in vitro bioaccesibility of ω‐3‐oils (salmon oil, SO; tuna oil, TO; enriched‐ω‐3 oil as triacylglycerols (TAGs), ω‐3‐TAG; and enriched‐ω‐3 oil as ethyl esters (EEs), ω‐3‐EE) was performed after treatment with pancreatin (pancreatic lipase as major lipolytic enzyme) at pH 7.5. Aliquots were taken at different times of digestion for analyzing the evolution of lipid products. The micellar phase (MP) formed at 120 min of digestion was isolated, its total lipid content was extracted and its composition in lipid products was analyzed. The rate of hydrolysis of ω‐3‐TAG concentrates was continuous throughout the time of reaction (51% hydrolysis of TAGs at 120 min), whereas the digestion of SO and TO was initially faster but stopped after 10 min of reaction (35 and 38% hydrolysis of TAGs at 120 min of SO and TO, respectively). A poor hydrolysis of EEs took place for the ω‐3‐EE oil (around 7% hydrolysis of EEs at 120 min). The MP of ω‐3‐TAG oil, SO, and TO mainly consisted of free fatty acids (FFAs) and MAGs. The MP from digested ω‐3‐EE oil consisted of FFAs and undigested EEs. Therefore, the highest degree of hydrolysis and inclusion of lipid products in the micellar structure was found for the ω‐3‐TAG oil, but compared to fish oils long times of digestion were required. This experience also shows for the first time the MP composition from ω‐3‐concentrates in the form of EEs. Practical applications: Commercial ω‐3 sources can be found as purified fish oil or concentrates in the form of TAGs, FFAs, and EEs. Despite differences exist regarding their intestinal metabolism, there is lack of information about the specific composition in lipolytic products of the absorbable fraction (MP) from ω‐3‐TAG or ω‐3‐EE concentrates. This comparative study showed that (i) the in vitro bioaccesibility of ω‐3‐polyunsaturated fatty acid (PUFA) seems to be better as ω‐3‐TAG concentrates than purified fish oils, but after long times of digestion; and (ii) the in vitro hydrolysis of ω‐3‐PUFA as EEs seems to be poor, at least after the activity of the major lipolytic enzyme of pancreatin, namely pancreatic lipase. Furthermore, the inclusion of EEs within micellar structures seems to be limited. These results contribute to the knowledge of the intestinal lipolysis of ω‐3 sources by showing the composition of the MP on lipid products for the first time.     

Postprandial Lipid Responses do not Differ Following Consumption of Butter or Vegetable Oil when Consumed with Omega-3 Polyunsaturated Fatty Acids

Dietary saturated fat (SFA) intake has been associated with elevated blood lipid levels and increased risk for the development of chronic diseases. However, some animal studies have demonstrated that dietary SFA may not raise blood lipid levels when the diet is sufficient in omega‐3 polyunsaturated fatty acids (n‐3PUFA). Therefore, in a randomised cross‐over design, we investigated the postprandial effects of feeding meals rich in either SFA (butter) or vegetable oil rich in omega‐6 polyunsaturated fatty acids (n‐6PUFA), in conjunction with n‐3PUFA, on blood lipid profiles [total cholesterol, low density lipoprotein cholesterol (LDL‐C), high density lipoprotein cholesterol (HDL‐C) and triacylglycerol (TAG)] and n‐3PUFA incorporation into plasma lipids over a 6‐h period. The incremental area under the curve for plasma cholesterol, LDL‐C, HDL‐C, TAG and n‐3PUFA levels over 6 h was similar in the n‐6PUFA compared to SFA group. The postprandial lipemic response to saturated fat is comparable to that of n‐6PUFA when consumed with n‐3PUFA; however, sex‐differences in response to dietary fat type are worthy of further attention.     

Synthesis of regioisomerically pure triacylglycerols containing n‐3 very long‐chain polyunsaturated fatty acids

There is growing scientific evidence that consumption of n‐3 very long‐chain polyunsaturated fatty acids (n‐3 VLC‐PUFA) helps in brain and eye development, and protects against a range of common degenerative diseases. This has provided the impetus to the scientists to develop new and renewable sources for these important fatty acids so that the food industry is able to produce and market products fortified with n‐3 VLC‐PUFA. The bioactive efficacy and stability of food products containing n‐3 VLC‐PUFA may be determined not only by the amount of n‐3 VLC‐PUFA present but also by the positional distribution of these acids within the triacylglycerol (TAG) molecules (regiopurity). Studies of the effects of positional distribution on the functionality of n‐3 VLC‐PUFA containing oils have been hampered by a general lack of pure TAG regioisomers for experimentation. This paper reviews methods that have been used for the synthesis of TAG regioisomers containing n‐3 VLC‐PUFA, with special reference to those in which one n‐3 VLC‐PUFA occurs in combination with two long‐chain saturated acids.     

In vitro antioxidant and in vivo antidiabetic,antihyperlipidemic activity of linseed oil against streptozotocin‐induced toxicity in albino rats

The intake of omega‐3 unsaturated fatty acids has a beneficial effect on insulin sensitivity in rats and in subjects with type 2 diabetes. It has been reported that these omega‐3 fatty acids are useful in the treatment of hypertriglyceridemia and in the enhancement of high‐density lipoprotein (HDL)‐cholesterol levels in diabetic patients. The present study was therefore aimed to evaluate the antioxidant, antihyperglycemic and antihyperlipidemic effect of L. usitatissimum fixed oil. The antioxidant activity was evaluated in vitro using 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) and hydrogen peroxide (H₂O₂) assay. The oil exhibited significant in vitro antioxidant activity in the DPPH and H₂O₂ assay. The oil (1, 2, 3 mL/kg) was further investigated against streptozotocin (STZ)‐induced hyperglycemia and hyperlipidemia in albino rats, subjected to 3 weeks of treatment. The oil manifested decrease in blood glucose and glycated hemoglobin levels at higher dose and significant dose dependent negating action on antioxidant enzymes in the heart, liver and kidney tissues. The oil also normalized the various hematological parameters and electrolyte levels in the STZ treated rats. Treatment with oil significantly increased the level of serum HDL and decreased the levels of total cholesterol, triglycerides, and low‐density lipoprotein‐cholesterol in STZ‐diabetic rats in comparison to normal control. The antioxidant, antihyperglycemic and antihyperlipidemic activity of the oil could be attributed to the presence of linolenic acid (ALA, 18:3 n‐3) and its metabolic products, eicosapentanoic acid (EPA, 20:5 n‐3) and docosahexanoic acid (DHA, 22:6 n‐3).     

Dietary Omega-3 Fatty Acids Prevented Adipocyte Hypertrophy by Downregulating DGAT-2 and FABP-4 in a Sex-Dependent Fashion

Obesity is characterized by an increase in fat mass primarily as a result of adipocyte hypertrophy. Diets enriched in omega (n)‐3 polyunsaturated fatty acids (PUFA) are suggested to reduce obesity, however, the mechanisms are not well understood. We investigated the effect of n‐3 PUFA on adipocyte hypertrophy and the key genes involved in adipocyte hypertrophy. Female C57BL/6 mice were fed semi‐purified diets (20 % w/w fat) containing high n‐3 PUFA before mating, during pregnancy, and until weaning. Male and female offspring were continued on high n‐3 PUFA (10 % w/w), medium n‐3 PUFA (4 % w/w), or low n‐3 PUFA (2 % w/w) diet for 16 weeks postweaning. Adipocyte area was quantified using microscopy, and gonadal mRNA expression of acyl CoA:diacylglycerol acyltransferase‐2 (DGAT‐2), fatty acid binding protein‐4 (FABP‐4) and leptin were measured. The high n‐3 PUFA group showed higher levels of total n‐3 PUFA in gonadal TAG compared to the medium and low n‐3 PUFA groups (P < 0.001). The high n‐3 PUFA male group had a lower adipocyte area compared to the medium and low n‐3 PUFA group (P < 0.001); however, no difference was observed in females. The high n‐3 PUFA male group showed lower mRNA expression of FABP‐4, DGAT‐2 and leptin compared to the low n‐3 PUFA group, with no difference in females. Plasma lipid levels were lower in the high n‐3 PUFA group compared to the other groups. Our findings show for the first time that n‐3 PUFA prevents adipocyte hypertrophy by downregulating FABP‐4, DGAT‐2 and leptin; the effects are however sex‐specific.     

Searching for health beneficial n‐3 and n‐6 fatty acids in plant seeds

Various plant seeds have received little attention in fatty acid research. Seeds from 30 species mainly of Boraginaceae and Primulaceae were analysed in order to identify potential new sources of the n‐3 PUFA α‐linolenic acid (ALA) and stearidonic acid (SDA) and of the n‐6 PUFA γ‐linolenic acid (GLA). The fatty acid distribution differed enormously between genera of the same family. Echium species (Boraginaceae) contained the highest amount of total n‐3 PUFA (47.1%), predominantly ALA (36.6%) and SDA (10.5%) combined with high GLA (10.2%). Further species of Boraginaceae rich in both SDA and GLA were Omphalodes linifolia (8.4, 17.2%, resp.), Cerinthe minor (7.5, 9.9%, resp.) and Buglossoides purpureocaerulea (6.1, 16.6%, resp.). Alkanna species belonging to Boraginaceae had comparable amounts of ALA (37.3%) and GLA (11.4%) like Echium but lower SDA contents (3.7%). Different genera of Primulaceae (Dodecatheon and Primula) had varying ALA (14.8, 28.8%, resp.) and GLA portions (4.1, 1.5%, resp.), but similar amounts of SDA (4.9, 4.5%, resp.). Cannabis sativa cultivars (Cannabaceae) were rich in linoleic acid (57.1%), but poor in SDA and GLA (0.8, 2.7%, resp.). In conclusion, several of the presented plant seeds contain considerable amounts of n‐3 PUFA and GLA, which could be relevant for nutritional purposes due to their biological function as precursors for eicosanoid synthesis. Practical applications: N‐3 PUFA are important for human health and nutrition. Unfortunately, due to the increasing world population, overfishing of the seas and generally low amounts of n‐3 PUFA in major oil crops, there is a demand for new sources of n‐3 PUFA. One approach involves searching for potential vegetable sources of n‐3 PUFA; especially those rich in ALA and SDA. The conversion of ALA to SDA in humans is dependent on the rate‐limiting Δ6‐desaturation. Plant‐derived SDA is therefore a promising precursor regarding the endogenous synthesis of n‐3 long‐chain PUFA in humans. The present study shows that, in addition to seed oil of Echium, other species of Boraginaceae (Cerinthe, Omphalodes, Lithospermum, Buglossoides) and Primulaceae (Dodecatheon, Primula), generally high in n‐3 PUFA (30–50%), contain considerable amounts of SDA (5–10%). Therefore, these seed oils could be important for nutrition.     

Interplay Between n-3 and n-6 Long-Chain Polyunsaturated Fatty Acids and the Endocannabinoid System in Brain Protection and Repair

The brain is enriched in arachidonic acid (ARA) and docosahexaenoic acid (DHA), long‐chain polyunsaturated fatty acids (LCPUFAs) of the n‐6 and n‐3 series, respectively. Both are essential for optimal brain development and function. Dietary enrichment with DHA and other long‐chain n‐3 PUFA, such as eicosapentaenoic acid (EPA), has shown beneficial effects on learning and memory, neuroinflammatory processes, and synaptic plasticity and neurogenesis. ARA, DHA and EPA are precursors to a diverse repertoire of bioactive lipid mediators, including endocannabinoids. The endocannabinoid system comprises cannabinoid receptors, their endogenous ligands, the endocannabinoids, and their biosynthetic and degradation enzymes. Anandamide (AEA) and 2‐arachidonoylglycerol (2‐AG) are the most widely studied endocannabinoids and are both derived from phospholipid‐bound ARA. The endocannabinoid system also has well‐established roles in neuroinflammation, synaptic plasticity and neurogenesis, suggesting an overlap in the neuroprotective effects observed with these different classes of lipids. Indeed, growing evidence suggests a complex interplay between n‐3 and n‐6 LCPUFA and the endocannabinoid system. For example, long‐term DHA and EPA supplementation reduces AEA and 2‐AG levels, with reciprocal increases in levels of the analogous endocannabinoid‐like DHA and EPA‐derived molecules. This review summarises current evidence of this interplay and discusses the therapeutic potential for brain protection and repair.     

Dietary High‐Oleic Acid Soybean Oil Dose Dependently Attenuates Egg Yolk Content of n‐3 Polyunsaturated Fatty Acids in Laying Hens Fed Supplemental Flaxseed Oil

Chickens can hepatically synthesize eicosapentaenoic acid (20:5 n‐3) and docosahexaenoic acid (22:6 n‐3) from α‐linolenic acid (ALA; 18:3 n‐3); however, the process is inefficient and competitively inhibited by dietary linoleic acid (LNA; 18:2 n‐6). In the present study, the influence of dietary high‐oleic acid (OLA; 18:1 n‐9) soybean oil (HOSO) on egg and tissue deposition of ALA and n‐3 polyunsaturated fatty acids (PUFA) synthesized from dietary ALA was investigated in laying hens fed a reduced‐LNA base diet supplemented with high‐ALA flaxseed oil (FLAX). We hypothesized that reducing the dietary level of LNA would promote greater hepatic conversion of ALA to very long‐chain (VLC; >20C) n‐3 PUFA, while supplemental dietary HOSO would simultaneously further enrich eggs with OLA without influencing egg n‐3 PUFA contents. Nine 51‐week‐old hens each were fed 0, 10, 20, or 40 g HOSO/kg diet for 12 weeks. Within each group, supplemental dietary FLAX was increased every 3 weeks from 0 to 10 to 20 to 40 g/kg diet. Compared to controls, dietary FLAX maximally enriched the total n‐3 and VLC n‐3 PUFA contents in egg yolk by 9.4‐fold and 2.2‐fold, respectively, while feeding hens 40 g HOSO/kg diet maximally attenuated the yolk deposition of ALA, VLC n‐3 PUFA, and total n‐3 PUFA by 37, 15, and 32%, respectively. These results suggest that dietary OLA is not neutral with regard to the overall process by which dietary ALA is absorbed, metabolized, and deposited into egg yolk, either intact or in the form of longer‐chain/more unsaturated n‐3 PUFA derivatives.     

Dietary ALA from Spinach Enhances Liver n-3 Fatty Acid Content to Greater Extent than Linseed Oil in Mice Fed Equivalent Amounts of ALA

Although several works have reported absorption rate differences of n‐3 polyunsaturated fatty acids (PUFA) bound to different lipid forms, such as ethyl ester, triacylglycerol (TAG), and phospholipids, no studies have investigated the effect of n‐3 PUFA from glycolipids (GL). The present study compared the fatty acid contents of tissue and serum lipids from normal C57BL/6J mice fed two types of α‐linolenic acid (ALA)‐rich lipids, spinach lipid (SPL), and linseed oil (LO). ALA was primarily present as the GL form in SPL, while it existed as TAG in LO. Supplementation of both lipids increased ALA and its n‐3 metabolites, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid, and decreased n‐6 PUFA, linoleic acid and arachidonic acid, in the livers, small intestines, and sera of the treated mice compared with those of the control group. When the comparison between the SPL and LO diets containing the same amount of ALA was conducted, the EPA and DPA levels in the liver lipids from mice fed the SPL diet were significantly higher than those fed the LO diet. Additionally, the total contents of n‐3 PUFA of lipids from the livers, small intestines, and sera of the SPL group were higher than those of the LO group.     

Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits

The catabolism and structure of high‐density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A‐I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL‐apo A‐I was evaluated by exogenous radiolabelling with iodine‐131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P < 0.001) associated with increased uremia, creatininemia, and cardiotoxicity. Large HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol‐to‐phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [¹³¹I]‐apo A‐I in the proteinuric rabbits was faster (FCR = 0.036 h^?1) compared to control rabbits group (FCR = 0.026 h^?1, P < 0.05). Apo E increased and apo A‐I decreased in HDL, whereas PON‐1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase‐1 activity, and a rise in the fractional catabolic rate of the [¹³¹I]‐apo A‐I.     

Association of L‐FABP T94A and MTP I128T Polymorphisms with Hyperlipidemia in Chinese Subjects

The purpose of this study was to evaluate the relation between the L‐FABP T94A and MTP I128T polymorphisms and hyperlipidemia in Chinese subjects. We recruited 390 volunteers: 201 hyperlipidemic and 189 healthy volunteers. The L‐FABP T94A and MTP I128T polymorphisms were genotyped using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP). Anthropometry, lipid profile, and liver function of the subjects were determined. We observed that male carriers of the L‐FABP A94 allele had significantly higher body weight (P = 0.012), higher body mass index (BMI) (P = 0.014), and higher plasma triacylglycerol levels (TAG) (P = 0.033) and lower ratios of high‐density lipoprotein cholesterol (HDL‐C) to total cholesterol (TC) (P = 0.008) than T94 homozygotes. The MTP T128 allele was associated with significantly lower serum TC (P < 0.001) and low‐density lipoprotein cholesterol (LDL‐C) (P < 0.001) levels in males. There was a direct correlation between the MTP T128 allele and a decreased risk of hyperlipidemia after adjusting for body mass index (OR = 0.327, 95 % CI: 0.178–0.600, P < 0.001). In conclusion, both the MTP I128T and the L‐FABP T94A polymorphisms can affect serum lipid levels in the Chinese population. The MTP T128 allele offers protection against hyperlipidemia in the Chinese population.     

n‐3 PUFA Induce Microvascular Protective Changes During Ischemia/Reperfusion

Ischemia/reperfusion (I/R) injury can occur in consequence of myocardial infarction, stroke and multiple organ failure, the most prevalent cause of death in critically ill patients. I/R injury encompass impairment of endothelial dependent relaxation, increase in macromolecular permeability and leukocyte‐endothelium interactions. Polyunsaturated fatty acids (n‐3 PUFA), such as eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) found in fish oil have several anti‐inflammatory properties and their potential benefits against I/R injury were investigated using the hamster cheek pouch preparation before and after ischemia. Before the experiments, hamsters were treated orally with saline, olive oil, fish oil and triacylglycerol (TAG) and ethyl ester (EE) forms of EPA and DHA at different daily doses for 14 days. Fish oil restored the arteriolar diameter to pre ischemic values during reperfusion. At onset and during reperfusion, Fish oil and DHA TAG significantly reduced the number of rolling leukocytes compared to saline and olive oil treatments. Fish oil, EPA TAG and DHA TAG significantly prevented the rise on leukocyte adhesion compared to saline. Fish oil (44.83 ± 3.02 leaks/cm²), EPA TAG (31.67 ± 2.65 leaks/cm²), DHA TAG (41.14 ± 3.63 leaks/cm²), and EPA EE (30.63 ± 2.25 leaks/cm²), but not DHA EE (73.17 ± 2.82 leaks/cm²) prevented the increase in macromolecular permeability compared to saline and olive oil (134.80 ± 1.49 and 121.00 ± 4.93 leaks/cm², respectively). On the basis of our findings, we may conclude that consumption of n‐3 polyunsaturated fatty acids, especially in the triacylglycerol form, could be a promising therapy to prevent microvascular damage induced by ischemia/reperfusion and its consequent clinical sequelae.     

Plasma Phospholipid Fatty Acid Profile is Altered in Both Septic and Non-Septic Critically Ill: A Correlation with Inflammatory Markers and Albumin

This study analyzes fatty acid (FA) composition in plasma lipids and erythrocyte phospholipids while comparing septic and non‐septic critically ill patients. The aim was to describe impacts of infection and the inflammatory process. Patients with severe sepsis (SP, n = 13); age‐, sex‐ and APACHE II score‐matched non‐septic critically ill with systemic inflammatory response syndrome (NSP, n = 13); and age‐/sex‐matched healthy controls (HC, n = 13) were included in a prospective case–control study during the first 24 h after admission to the intensive care unit. In both SP and NSP, lower n‐6 polyunsaturated FA (PUFA) accompanied by higher proportions of monounsaturated FA (MUFA) in plasma phospholipids (PPL) was observed relative to HC. MUFA proportion was negatively correlated with n‐6 PUFA, high density lipoprotein cholesterol (HDL‐C), and albumin. MUFA was positively correlated with C‐reactive protein (CRP), procalcitonin (PCT), interleukins (IL‐6, IL‐10), oxidized low density lipoproteins (ox‐LDL), and conjugated dienes (CD). In both SP and NSP, inflammatory and lipid peroxidation markers were significantly higher—CRP (p < 0.001; p = 0.08), IL‐6, IL‐10, TNF‐α (p < 0.01, p = 0.06), ox‐LDL, and CD while total cholesterol, HDL‐C, LDL‐C albumin, and 20:4n‐6/22:6n‐3 and n‐6/n‐3 ratios were lower compared to HC. In conclusion, the changes in plasma lipid FA profile relate to the intensity of inflammatory and peroxidative response regardless of insult etiology. The lower MUFA and higher n‐6 PUFA proportions in PPL were inversely correlated with cholesterol and albumin levels.     

Lipase‐mediated hydrolysis of flax seed oil for selective enrichment of α‐linolenic acid

Polyunsaturated fatty acids (PUFA) are important ingredients of human diet because of their prominent role in the function of human brain, eye and kidney. α‐Linolenic acid (ALA), a C18, n‐3 PUFA is a precursor of long chain PUFA in humans. Commercial lipases of Candida rugosa, Pseudomonas cepacea, Pseudomonas fluorescens, and Rhizomucor miehei were used for hydrolysis of flax seed oil. Reversed phase high performance liquid chromatography followed by gas chromatography showed that the purified oil contained 12 triacylglycerols (TAGs) with differences in fatty acid compositions. Flax seed oil TAGs contained α‐linolenic acid (50%) as a major fatty acid while palmitic, oleic, linoleic made up rest of the portion. Among the four commercial lipases C. rugosa has preference for ALA, and that ALA was enriched in free fatty acids. C. rugosa lipase mediated hydrolysis of the TAGs resulted in a fatty acid mixture that was enriched in α‐linolenic to about 72% yield that could be further enriched to 80% yield by selective removal of saturated fatty acids by urea complexation. Such purified ALA can be used for preparation of ALA‐enriched glycerides. Practical applications : This methodology allows purifying ALA from fatty acid mixture obtained from flax seed oil by urea complexation.     

The impact of dietary mono‐ and poly‐unsaturated fatty acids on risk factors for atherosclerosis in humans

The fatty acid composition of the diet has various effects on atherosclerosis risk factors. Dietary saturated fatty acids (SFA) and trans‐unsaturated fatty acids increase the low‐density lipoprotein (LDL)‐/high‐density lipoprotein (HDL)‐cholesterol ratio in serum, while these fats do not have a significant bearing on serum triglyceride levels. By contrast, dietary monounsaturated fatty acids (MUFA), n‐6 polyunsaturated fatty acids (PUFA), and α‐linolenic acid (C18:3n‐3) similarly reduce LDL cholesterol concentrations, while their influence on serum HDL cholesterol and triglycerides is not appreciable. Dietary long‐chain n‐3 PUFA slightly increase serum LDL cholesterol concentrations, but are nevertheless considered salubrious with regard to serum lipids due to the distinct triglyceride‐lowering effects. MUFA‐rich compared to n‐6 PUFA‐rich diets strongly reduce the in vitro oxidizability of LDL. The available studies on this subject also suggest that n‐3 PUFA in the small amounts usually present in the diet are not unduly harmful. These findings are consistent with reports from observational studies: the amount of SFA is positively and the amount of MUFA and n‐6 PUFA in the diet is inversely associated with the risk of cardiovascular disease in most epidemiological studies. The available studies have had an impact on current dietary guidelines, which unanimously recommend that most of the dietary fat should be in the form of MUFA, while the amount of SFA and trans fatty acids in the diet should be as low as possible.     

Hypolipidemic Effects of Phospholipids (PL) Containing n-3 Polyunsaturated Fatty Acids (PUFA) Are Not Dependent on Esterification of n-3 PUFA to PL

Phospholipids (PL) containing n‐3 polyunsaturated fatty acids (PUFA) have beneficial effects of maintaining and promoting health compared with triacylglycerols (TAG) containing n‐3 PUFA or general PL. This study evaluated the effects of dietary PL containing n‐3 PUFA and elucidated the effects of the glycerophosphate structure and n‐3 PUFA on fatty acid (FA) metabolism in rats. Rats were fed a basal diet containing soybean oil alone, TAG containing n‐3 PUFA (1.8 %), soybean PL (2.7 %), PL containing n‐3 PUFA (2.7 %), or TAG containing n‐3 PUFA (1.8 %) + soybean PL (2.7 %). The present n‐3 PUFA‐supplemented diets had similar FA compositions, and the PL diets had similar PL compositions. TAG containing n‐3 PUFA reduced serum TAG contents, but did not affect serum cholesterol contents compared with soybean oil alone. PL diets containing n‐3 PUFA and the combination of TAG containing n‐3 PUFA and soybean PL resulted in decreased serum and liver TAG contents compared with the diet containing soybean oil alone, reflecting enhanced liver FA β‐oxidation. The results of this study show that TAG containing n‐3 PUFA with added soybean PL affects serum and liver TAG and cholesterol contents to a similar degree as PL containing n‐3 PUFA. TAG containing n‐3 PUFA and soybean PL are widely used as functional food ingredients and pharmaceutical constituents and are inexpensive compared with PL containing n‐3 PUFA. Therefore, the combination of TAG containing n‐3 PUFA and soybean PL has potential as a useful and inexpensive component of functional foods.     

Lipase selectivity toward fatty acids commonly found in fish oil

The main objective of this study was to compare the fatty acid selectivity of numerous commercially available lipases toward the most ubiquitous fatty acids present in fish oils in form of their corresponding ethyl esters. Special interest was taken in their ability to separate the n‐3 long‐chain polyunsaturated fatty acids (PUFA), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from the more saturated fatty acids as well as exploiting the putative discrimination between these highly valuable n‐3 PUFA. Hydrolysis of sardine oil ethyl esters in a Tris buffer solution by 12 microbial lipases is described. The results reveal that all of the lipases strongly discriminate against the n‐3 PUFA and prefer the more saturated fatty acids as substrates. Most of the lipases discriminate between EPA and DHA in favor of EPA, however, 2 bacterial lipases from Pseudomonas were observed to prefer DHA to EPA. Digestive lipolytic enzymes isolated from salmon and rainbow trout intestines displayed reversed fatty acid selectivity when their fish oil triacylglycerol hydrolysis was studied. Thus, the n‐3 PUFA including EPA and DHA were observed to be hydrolyzed at a considerably higher rate than the more saturated fatty acids.