Beneficial effects of monounsaturated fatty acid-rich blended oils with an appropriate polyunsaturated/saturated fatty acid ratio and a low n-6/n-3 fatty acid ratio on the health of rats.

BACKGROUND: The effects of dietary fat on health are influenced by its fatty acid profile. We aimed to determine the effects of monounsaturated fatty acid (MUFA)-rich blended oils (BO) containing a balance of polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) and with a low n-6/n-3 PUFA ratio on the health of rats fed normal or high-fat diets. The BO was obtained by mixing red palm oil, rice bran oil (RO), tea seed oil and flaxseed oil in appropriate proportions. RESULTS: BO consumption reduced the serum low-density lipoprotein cholesterol (LDL-C), non-esterified fatty acid (NEFA), insulin (INS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 (IL-1), high-sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA), lipid peroxide (LPO) and oxidized LDL (ox-LDL) concentrations and the homeostasis model assessment of insulin resistance (HOMA-IR); it increased the high-density lipoprotein cholesterol (HDL-C), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) concentrations, and the bone mineral density (BMD) versus control oil-containing normal and high-fat diets. BO also reduced the triglyceride (TG), hs-CRP, MDA, ox-LDL and reactive oxygen species (ROS) concentrations; and increased the serum HDL-C and SOD, and BMD versus RO-containing high-fat diets. Finally, BO reduced the glucose (GLU) and INS, and HOMA-IR; it increased HDL-C, SOD, femoral weight and BMD versus RO-containing normal diets. CONCLUSION: BOs with an appropriate fatty acid profile have beneficial effects on the glucolipid metabolism, inflammation, oxidative stress and bone quality of rats when included in both normal and high-fat diets. © 2022 Society of Chemical Industry.

Effect of including n-3/ n-6 fatty acid feed sources in diet on fertility and hatchability of broiler breeders and post-hatch performance and carcass parameters of progeny.

OBJECTIVE: The present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny. METHODS: Two hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded. RESULTS: The results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (P>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (P<0.05) higher late embryonic mortality compared to other three treatments. CONCLUSION: It was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% Flax seed oil) in broiler breeders' diet can reduced late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

Seasonal variations of fatty acid profile in different tissues of farmed bighead carp (Aristichthys nobilis).

Bighead carp (Aristichthys nobilis) is one of the major farmed species of freshwater fish in China. Byproduct volume of bighead carp is significant at up to 60 % of whole fish weight. A better understanding of the nutritional composition is needed to optimize the use of these raw materials. The objective of this research was to characterize seasonal variations of fatty acid profile in different tissues (heads, bones, skin, scales, viscera, muscle and fins) of farmed bighead carp. The fatty acid composition of farmed bighead carp varied significantly with seasons and tissues. The highest lipid content was determined in viscera while the highest EPA and DHA composition were observed in muscle compared to the other tissues. Significantly higher ΣEPA+DHA (%) was recorded in all tissues in summer (June) when compared with those of the other three seasons (p < 0.05). The n-3/n-6 fatty acid ratios in summer ranged from 3.38 to 3.69, nearly three times the ratios of the other three seasons. The results indicated that farmed bighead carp caught in summer could better balance the n-3 PUFA needs of consumers. The byproducts of bighead carp can be utilized for the production of fish oil.

Circulating plasma phospholipid fatty acid levels as a biomarker of habitual dietary fat intake: The INTERMAP/INTERLIPID Study.

BACKGROUND: Accurate assessment of fat intake is essential to examine relationships between diet and disease risk. However, estimating individual intakes of fat quantity by dietary assessment is difficult. OBJECTIVE: We assessed the association of plasma phospholipid fatty acid levels with dietary intake of fatty acids in the INTERMAP/INTERLIPID study, conducted with a standardized protocol. METHODS: The study participants were 1339 men and women ages 40-59 years from five Japanese populations one from Hawaii; four from Japan. Fatty acid intake was estimated from four standardized 24-hour dietary recalls. Plasma phospholipid fatty acid composition was analyzed by gas chromatography. We illustrated the relationship between intake and circulating fatty acid levels using Spearman's rank-correlation coefficients, mean, and median values. RESULTS: Spearman's rank-correlation coefficients between intake (g/d) and circulating fatty acid levels (µg/ml) were -0.03 to 0.21 for saturated fatty acids and monounsaturated fatty acids and -0.04 to 0.32 for trans fatty acids. The coefficients for essential n-3 and n-6 fatty acids were moderate to high, especially for eicosapentaenoic acid (EPA), 0.60; docosahexaenoic acid (DHA), 0.41; and EPA+DHA, 0.51. The circulating levels and intake of marine-derived n-3 fatty acids showed a linear association, at least for the intake of EPA+DHA up to 2.1 g/d. CONCLUSION: We observed high correlation between intake and circulating levels of marine-derived n-3 fatty acids in participants from Japanese and Japanese-American populations with high and low fish intake. Plasma phospholipid marine-derived n-3 fatty acid measurements are a simple and reliable biomarker for assessing dietary intake.

Effects of Soybean and Linseed Oils Calcium Salts and Starter Protein Content on Growth Performance, Immune Response, and Nitrogen Utilization Efficiency in Holstein Dairy Calves.

This study aimed to investigate the interaction of fatty acid (FA) source [calcium salt of soybean oil (n-6 FA) vs. calcium salt of linseed oil (n-3 FA) both 3% DM basis] with protein content (18% vs. 22% CP, based on DM) on growth performance, blood metabolites, immune function, skeletal growth indices, urinary purine derivatives (PD), and microbial protein synthesis (MPS) in young dairy calves. Forty 3-day-old calves (20 females and 20 males) with a starting body weight (BW) of 40.2 kg were assigned in a completely randomized block design in a 2 × 2 factorial arrangement of treatments. Experimental diets were: (1) n-6 FA with 18% CP (n-6-18CP), (2) n-6 FA with 22% CP (n-6-22CP), (3) n-3 FA with 18% CP (n-3-18CP), and (4) n-3 FA with 22% CP (n-3-22CP). Starter feed intake and average daily gain (ADG) were not influenced by experimental diets (p > 0.05). However, before weaning and the entire period, feed efficiency (FE) was greater in calves fed n-3 FA compared to n-6 FA (p < 0.05). Heart girth (weaning, p < 0.05) and hip height (weaning, p < 0.05 and final, p < 0.01) were highest among experimental treatments in calves who received n-3-22CP diets. The greatest blood glucose (p < 0.05) and insulin (p < 0.01) concentrations in the pre-weaning period and the lowest serum concentration of tumor necrosis factor (before weaning, p < 0.05) were observed in calves fed the n-3-22CP diet. However, the greatest blood urea N (before weaning, p < 0.05; after weaning, p < 0.05) and urinary N excretion (p < 0.05) were found in calves fed n-6-22CP diets compared to other experimental arrangements. In conclusion, offering calves with Ca-salt of n-3 FA along with 22% CP content may be related to improved nitrogen efficiency and immune function.

Dietary and Plasma Phospholipid Profiles in Vegans and Omnivores-Results from the RBVD Study.

Over the last few years, the vegan diet has become increasingly popular in Germany. It has been proposed that this diet is generally lower in fat, but less is known about the impact on fatty acid (FA) profiles. Therefore, the cross-sectional "Risks and Benefits of a Vegan Diet" (RBVD) study (n = 72) was used to investigate dietary FA intake as well as plasma phospholipid FA in vegans (n = 36) compared to omnivores (n = 36). Vegans had a significantly lower dietary intake of total fat (median 86 g/day, IQR 64−111) in comparison to omnivores (median 104 g/day, IQR 88−143, p = 0.004). Further, vegans had a lower intake of saturated fatty acids (SFA) (p < 0.0001) and monounsaturated fatty acids (MUFA) (p = 0.001) compared to omnivores. Vegans had a higher intake in total polyunsaturated fatty acids (PUFA), omega-3 and omega-6 PUFA compared to omnivores, but without statistical significance after Bonferroni correction. According to plasma phospholipid profiles, relatively lower proportions of SFA (p < 0.0001), total trans fatty acids (TFA) (p = 0.0004) and omega-3-FA (p < 0.0001), but higher proportions of omega-6-FA (p < 0.0001) were observed in vegans. With the exception of omega-3 PUFA, a vegan diet is associated with a more favorable dietary fat intake and more favorable plasma FA profiles and therefore may reduce cardiovascular risk.

Maternal Supplementation with Cow's Milk Naturally Enriched with PUFA Alters the Metabolism of Sows and the Fatty Acid Profile of the Offspring.

The study aimed to evaluate the supplementation of gilts with cow's milk naturally enriched with n-3 and n-6 polyunsaturated fatty acids (PUFA) on reproductive outcomes, and the serum biochemical and FA profile of swine females and their offspring. During 316 days, 30 gilts were distributed into three groups: (1) Control, fed a basal diet + milk from cows without oil; (2) n-3, fed a basal diet + milk from cows fed a diet enriched with linseed oil; (3) n-6, fed a basal diet + milk from cows fed a diet enriched with soybean oil. The gilts receiving the diets containing PUFA had higher serum urea and very-low-density lipoprotein levels and lower serum total protein and low-density lipoprotein levels compared to the Control group. Females supplemented with n-3 presented higher serum palmitic acid and γ-linolenic acid levels than those fed n-6. Piglets from the Control group were heavier at birth than those from females supplemented with enriched milk. The piglets from females receiving enriched milk had 140 g higher body weight from 1 to 21 days old compared to the Control group, and greater average daily weight gain from 7 to 14 days old. The serum eicosapentaenoic acid level of piglets fed n-3 was 69% higher than those fed n-6, which reduced the AA/EPA ratio. Gilts supplemented with PUFA-enriched cow's milk showed changes in their serum palmitic and γ-linolenic acid levels, in addition to improved performance, EPA concentration and consequently reduced AA/EPA ratio in their piglets, demonstrating beneficial results for their progeny.

Trends in the Intake of Fatty Acids and Their Food Source According to Obese Status Among Korean Adult Population Using KNHANES 2007-2017.

BACKGROUND: Increasing obesity rates are related to energy intake with carbohydrate and fat ratio. Using Korean National Health and Nutrition Examination Survey 2007-2017 data, we examined the hypothesis that the fat intake and food sources of dietary fats had changed over the last 10 years according to gender and obesity status in adult population ≥19 years. METHODS: The food intake of each participant was collected by the 24-hour recall method, and nutrient intake including different fatty acids was calculated. The fatty acid intakes from 7 food groups were determined according to gender and obesity status. RESULTS: Body mass index increased in both genders of the obese group over the decade, but it decreased in the normal-weight group. In men, energy intake was higher in the obese group than in the lean group, but the opposite trend was shown in women. Total fat intake including various fatty acids continuously and sharply increased in both men and women until 2016, then slightly declined only in men. The source of saturated fatty acid (SFA) intake was mainly from the animal food group in men and women regardless of obese status, and SFA and monounsaturated fatty acid from the animal food group gradually increased over time in both genders. N-3 fatty acid intake markedly decreased from fish and crabs and increased from sauces and nuts regardless of genders and the obese status from 2008 to 2017. Polyunsaturated fatty acid and N-6 fatty acid intake increased from bread, cookies, sauces, and nuts regardless of genders and obesity status. CONCLUSION: Fat intake was higher in obese men, but this was opposite in women. The N-3 fatty acid intake from seafood should increase, and the fat composition in sauce needs to be modulated to increase N-3 fatty acids.

Fatty Acid Metabolite Profiling Reveals Oxylipins as Markers of Brown but Not Brite Adipose Tissue.

Metabolites of omega-6 and omega-3 polyunsaturated fatty acids are important signaling molecules implicated in the control of adipogenesis and energy balance regulation. Some of these metabolites belonging to the group of oxylipins have been associated with non-shivering thermogenesis in mice mediated by brown or brite adipose tissue. We aimed to identify novel molecules with thermogenic potential and to clarify the relevance of these findings in a translational context. Therefore, we characterized and compared the oxylipin profiles of murine and human adipose tissues with different abundance of brown or brite adipocytes. A broad panel of 36 fatty acid metabolites was quantified in brown and white adipose tissues of C57BL/6J mice acclimatized to different ambient temperatures and in biopsies of human supraclavicular brown and white adipose tissue. The oxylipin profile of murine brite adipose tissue was not distinguishable from white adipose tissue, suggesting that adipose tissue browning in vivo is not associated with major changes in the oxylipin metabolism. Human brown and white adipose tissue also exhibited similar metabolite profiles. This is in line with previous studies proposing human brown adipose tissue to resemble the nature of murine brite adipose tissue representing a heterogeneous mixture of brite and white adipocytes. Although the global oxylipin profile served as a marker for the abundance of thermogenic adipocytes in bona fide brown but not white adipose tissue, we identified 5-HETE and 5,6-EET as individual compounds consistently associated with the abundance of brown or brite adipocytes in human BAT and murine brite fat. Further studies need to establish whether these candidates are mere markers or functional effectors of thermogenic capacity.

Alpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet: Do They Require Dietary Reference Intake/Adequate Intake Special Consideration?

Good sources of the long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) include cold-water fish and seafood; however, vegan diets (VGNs) do not include animal-origin foods. Typically, US omnivores obtain enough dietary EPA and DHA, but unless VGNs consume algal n-3 supplements, they rely on endogenous production of long-chain fatty acids. VGN diets have several possible concerns: (1) VGNs have high intakes of linoleic acid (LA) as compared to omnivore/non-vegetarian diets. (2) High intakes of LA competitively interfere with the endogenous conversion of alpha-linolenic acid (ALA) to EPA and DHA. (3) High somatic levels of LA/low ALA indicate a decreased ALA conversion to EPA and DHA. (4) Some, not all VGNs meet the Dietary Reference Intake Adequate Intake (DRI-AI) for dietary ALA and (5) VGN diets are high in fiber, which possibly interferes with fat absorption. Consequently, health professionals and Registered Dietitians/Registered Dietitian Nutritionists working with VGNs need specific essential fatty acid diet guidelines. The purpose of this review was: (1) to suggest that VGNs have a DRI-AI Special Consideration requirement for ALA and LA based on VGN dietary and biochemical indicators of status and (2) to provide suggestions to ensure that VGNs receive adequate intakes of LA and ALA.

Association of Dietary n3 and n6 Fatty Acids Intake with Hypertension: NHANES 2007-2014.

We conducted this cross-sectional study in the American general population to explore the association of dietary n3 and n6 fatty acids intake and the risk of hypertension. We used data from the National Health and Nutrition Examination Survey (NHANES) 2007-2014 in this study. We obtained dietary n3 and n6 fatty acids data through two 24 h dietary recall interviews and n3, n6 fatty acids intake were adjusted by weight. We defined hypertension as now taking prescribed medicine for hypertension or blood pressure above 130/80 mmHg. We applied binary logistic regression, multinomial logistic regression, and restricted cubic spline to evaluate the associations of dietary n3 and n6 fatty acids intake with hypertension. A total of 18,434 participants were included in this study. In the multivariate-adjusted model 2, the odds ratios (ORs) with 95% confidence interval (CI) of hypertension were 0.58 (0.49-0.68), 0.53 (0.45-0.63), and 0.92 (0.80-1.06) for the highest versus the lowest tertile of dietary n3, n6 fatty acids intake and n6:n3 ratio, respectively. Further excluded participants with hypertension history, the ORs with 95% CI of newly diagnosed hypertension were 0.60 (0.50-0.73), 0.52 (0.43-0.62), and 0.95 (0.79-1.14) for the highest versus lowest tertile of dietary n3, n6 fatty acids intake and n6:n3 ratio, respectively. Dose-response analyses showed that the risk of hypertension was associated with dietary n3 and n6 fatty acids intake. Our study suggested that dietary n3 and n6 fatty acids intake were inversely associated with the risk of hypertension in US adults.

Relationship between Nutrition Intake and Estimated Glomerular Filtration Rate in Korean Adults (30-65 years) from the Korea National Health and Nutrition Examination Survey 2013-2014.

This study aimed to examine the relationship between nutrition intake and estimated glomerular filtration rate (eGFR) indicating kidney function in Korean individuals without diabetes or cardiovascular disease. Study participants from the Korea National Health and Nutrition Examination Survey 2013-2014 (n = 4,378, 30-65 years) were classified by their eGFR levels (mL/min/1.732 m2): ≥ 120 (n = 299), 119-105 (n = 789), 104-90 (n = 1,578), 89-60 (n = 1,685), < 60 (n = 27). After adjusted for confounding factors (age, sex, cigarette smoking, alcohol drinking, total caloric intake [TCI], income status, education level, body mass index, and physical activity), blood pressure, low-density lipoprotein (LDL) cholesterol, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, fasting glucose, and glycated hemoglobin were higher, and high density lipoprotein cholesterol levels were lower in participants with lower eGFR levels than those with higher eGFR levels. n-3 fatty acid (FA) and n-6 FA (% of TCI/day) intake were also significantly higher in participants with higher eGFR levels than in those with lower eGFR levels. Based on the above results, participants were subdivided into 3 groups according to n-6 FA intake levels (Q1: ≥ 2.93%, n = 1,462; Q2: 2.92%-1.88%, n = 1,463; Q3: < 1.88%, n = 1,453). People consuming higher n-6 FAs, particularly the Q1 group showed higher eGFR levels and lower levels of LDL cholesterol and creatinine. In conclusion, higher intake of n-6 FAs within the range of dietary reference may be beneficial to maintain healthy kidney function.

Relationship between Dietary n-6 Fatty Acid Intake and Hypertension: Effect of Glycated Hemoglobin Levels.

The relationship between dietary n-6 fatty acids and hypertension is not clear. The metabolic products of n-6 fatty acids include those that control blood pressure, such as prostaglandin and thromboxane, and that differ depending on the extent of glucose tolerance. This cross-sectional study investigated the association of dietary n-6 fatty acid intake on hypertension, and the effects of glycated hemoglobin (HbA1c) value in 633 Japanese subjects aged 40 years and older. Dietary intake was measured using a validated brief self-administered diet history questionnaire. We defined hypertension as the use of antihypertensive medication or a blood pressure of 140/90 mmHg. The prevalence of hypertension was 55.3%. A high n-6 fatty acids intake inversely correlated with hypertension in subjects with HbA1c values less than 6.5% (odds ratio, 0.857; 95% confidence interval, 0.744 to 0.987). On the contrary, in subjects with an HbA1c value of 6.5% or higher, the n-6 fatty acids intake was significantly associated with hypertension (odds ratio, 3.618; 95% confidence interval, 1.019 to 12.84). Regular dietary n-6 fatty acid intake may contribute to the prevention and treatment of hypertension in a healthy general population. By contrast, in subjects with diabetes, regular n-6 fatty acids intake may increase the risk of hypertension.

Different effects of γ-linolenic acid (GLA) supplementation on plasma and red blood cell phospholipid fatty acid composition and calcium oxalate kidney stone risk factors in healthy subjects from two race groups with different risk profiles pose questions about the GLA-arachidonic acid-oxaluria metabolic pathway: pilot study.

Fatty acid (FA) composition of phospholipids in plasma and red blood cells (RBC) can influence calciuria, oxaluria and renal stone formation. In this regard, the ratio of arachidonic acid (AA) and its precursor linoleic acid (LA) appears to be important. Administration of γ-linolenic acid (GLA) has been shown to increase the concentration of dihomo-gamma linoleic acid (DGLA) relative to AA indicating that it may attenuate biosynthesis of the latter. Such effects have not been investigated in race groups having difference stone occurrence rates. Black (B) and white (W) healthy males ingested capsules containing linoleic acid (LA) and GLA, for 30 days. Plasma and RBC total phospholipid (TPL) FA profiles, serum and 24 h urine biomarkers of hypercalciuria and urinary stone risk factors were determined on days 0 and 30. Data were tested for statistical significance using GraphPadInstat version 3.02. Concentration and percentage content of DGLA in plasma TPL increased in W but not in B. Arachidonic acid (AA) did not change in either group. There was no change in calcium excretion in either group but oxalate and citrate excretion increased in W. We suggest that elongation of GLA to DGLA may occur more rapidly than desaturation of DGLA to AA in W and that depressed activity of the enzyme elongase may occur in B. Calciuric and citraturic effects may be dependent on the quantity of LA or on the mass ratio of LA/GLA in the FA supplement. Questions about the mooted DGLA-AA-oxaluria pathway arise. We speculate that there exists a potential for using GLA as a conservative treatment for hypocitraturia. The observation of different responses in B and W indicates that such differences may play a role in stone formation and prevention.

Differential partitioning of rumen-protected n-3 and n-6 fatty acids into muscles with different metabolism.

Bioavailability of polyunsaturated fatty acids (PUFA) in ruminants is enhanced by their protection from ruminal biohydrogenation. Both n-3 and n-6 PUFA fulfil important physiological functions. We investigated potentially different incorporation patterns of these functional PUFA into three beef muscles with different activity characteristics. We supplemented 33 Angus heifers with rumen-protected oils characterized either by mainly C18:2 n-6 (linoleic acid (LA) in sunflower oil) or by C20:5 (eicosapentaenoic acid (EPA)) and C22:6 (docosahexaenoic acid (DHA)), both prevalent n-3 PUFA in fish oil. Contents and proportions of n-3 and n-6 PUFA of total fatty acids were elevated in the muscles of the respective diet group but they were partitioned differently into the muscles. For EPA and DHA, but not for LA, the diet effect was more distinct in the extensor carpi radialis compared to longissimus thoracis and biceps femoris. Partitioning of PUFA in metabolism could be related to muscle function. This has to be confirmed in other muscles, adipose tissues and organs.

Application of Silver Ion High-Performance Liquid Chromatography for Quantitative Analysis of Selected n-3 and n-6 PUFA in Oil Supplements.

The aim of this study was to develop a simple method for simultaneous determination of selected cis/cis PUFA-LNA (18:2), ALA (18:3), GLA (18:3), EPA (20:5), and DHA (22:6) by silver ion high-performance liquid chromatography coupled to a diode array detector (Ag-HPLC-DAD). The separation was performed on three Luna SCX Silver Loaded columns connected in series maintained at 10 °C with isocratic elution by 1% acetonitrile in n-hexane. The applied chromatographic system allowed a baseline separation of standard mixture of n-3 and n-6 fatty acid methyl esters containing LNA, DHA, and EPA and partial separation of ALA and GLA positional isomers. The method was validated by means of linearity, precision, stability, and recovery. Limits of detection (LOD) for considered PUFA standard solutions ranged from 0.27 to 0.43 mg L(-1). The developed method was used to evaluate of n-3 and n-6 fatty acids contents in plant and fish softgel oil capsules, results were compared with reference GC-FID based method.

The Pattern of Fatty Acids Displaced by EPA and DHA Following 12 Months Supplementation Varies between Blood Cell and Plasma Fractions.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are increased in plasma lipids and blood cell membranes in response to supplementation. Whilst arachidonic acid (AA) is correspondingly decreased, the effect on other fatty acids (FA) is less well described and there may be site-specific differences. In response to 12 months EPA + DHA supplementation in doses equivalent to 0-4 portions of oily fish/week (1 portion: 3.27 g EPA+DHA) multinomial regression analysis was used to identify important FA changes for plasma phosphatidylcholine (PC), cholesteryl ester (CE) and triglyceride (TAG) and for blood mononuclear cells (MNC), red blood cells (RBC) and platelets (PLAT). Dose-dependent increases in EPA + DHA were matched by decreases in several n-6 polyunsaturated fatty acids (PUFA) in PC, CE, RBC and PLAT, but were predominantly compensated for by oleic acid in TAG. Changes were observed for all FA classes in MNC. Consequently the n-6:n-3 PUFA ratio was reduced in a dose-dependent manner in all pools after 12 months (37%-64% of placebo in the four portions group). We conclude that the profile of the FA decreased in exchange for the increase in EPA + DHA following supplementation differs by FA pool with implications for understanding the impact of n-3 PUFA on blood lipid and blood cell biology.

Effects of chronic administration of arachidonic acid on lipid profiles and morphology in the skeletal muscles of aged rats.

Arachidonic acid (20:4n-6, ARA) is a major component of the cell membrane, whereas ARA-derived eicosanoids are formed when cells are damaged. Aging is associated with an accretion of oxidative stress in skeletal muscles. In this study, we examined the effects of chronic administration (13 weeks) of ARA (240 mg/kg/day) on fatty acid composition, antioxidative status, and morphology of slow (soleus muscles) and fast (extensor digitorum longus muscles; EDL)-twitch muscles in aged rats (21 months old). The level of reactive oxygen species was higher in the EDL of ARA-administered rats than in that of control rats. ARA administration decreased the muscle cell volumes and increased the number of slow myosin heavy chain (MHC)-positive cells in the EDL. The relative content of MHC2X was increased whereas the relative content of MHC2B was decreased in the EDL of ARA-administered rats. These results suggest that ARA deposition in the fast-twitch muscle of aged rats reduced cell volume with an increase in oxidative stress.