LCn-3 PUFA Research Articles

Long-chain n-3 polyunsaturated fatty acid supplementation and neuromuscular function in older adults.

This review aims to explore the latest research investigating the effects of marine-derived long-chain n -3 polyunsaturated fatty acid (LC n -3 PUFA) supplementation on neuromuscular function in older adults. Ageing results in a decline in skeletal muscle strength and mass. There is growing evidence that LC n -3 PUFA supplementation increases muscle strength and mass in healthy older adults, yet the mechanisms underlying these effects remain elusive. Recent studies investigating LC n -3 PUFA supplementation have demonstrated effects on neuromuscular function such as increases in the compound muscle action potential (M-wave) amplitude and surface electromyography alongside increases in muscular strength. Therefore, evidence suggests that LC n -3 PUFA may elicit a beneficial effect at the neuromuscular junction and possess neuroprotective properties in older adults. LC n -3 PUFA supplementation may increase or maintain neuromuscular function throughout the ageing process. Further research is warranted to investigate the long-term effects LC n -3 PUFA supplementation on neuromuscular outcomes such as single motor unit properties and cortical/supraspinal networks, utilizing state-of-the-art techniques in neuromuscular physiology.

The effect of long chain n-3 fatty acid supplementation on muscle strength in older adults: A systematic review and meta-analysis

Muscle strength and mass decline as we age, typically starting around 35–40 years, and can eventually lead to the development of sarcopenia(1). There are currently no effective drug treatments available for either the prevention or treatment of this condition(2) and whilst resistance exercise has efficacy(3) its effectiveness is limited due to issues with uptake and adherence(4). However, emerging research suggests that nutrition may offer a potentially effective approach to delay the age-related decline in muscle mass and function among older individuals(5), with LCn-3 PUFA emerging as a strong candidate.The main objective of the current study was to perform a systematic literature review with the purpose of exploring the impact of long-chain n-3 polyunsaturated fatty acid (LCn-3 PUFA) relative to control oil supplementation on muscle strength, with secondary outcomes of muscle mass and physical function in older individuals under conditions of habitual physical activity/exercise.The review protocol was registered with PROSPERO (CRD42021267011) and followed the guidelines outlined in the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement(6). The search for relevant studies was performed utilizing databases such as PubMed, EMBASE, CINAHL, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) up to June 2023. Randomized controlled trials (RCTs) in older adults comparing the effects of LCn-3 PUFA with a control oil supplement on muscle strength were included.Five studies(7,8,9,10,11) involving a total of 488 participants (348 females and 140 males) were identified that met the specified inclusion criteria and were included. Upon analyzing the collective data from these studies, it was observed that supplementation with LCn-3 PUFA did not have a significant impact on grip strength (standardized mean difference (SMD) 0.61, 95% confidence interval [−0.05, 1.27]; p = 0.07) in comparison to the control group. However, there was a considerable level of heterogeneity among the studies (I2 = 90%; p < 0.001). As secondary outcomes were only measured in a few studies, with significant heterogeneity in methods, meta-analyses of muscle mass and functional abilities were not performed. Papers with measures of knee extensor muscle mass as an outcome (n = 3) found increases with LCn-3 PUFA supplementation, but studies measuring whole body lean/muscle mass (n = 2) and functional abilities (n = 4) reported mixed results.With a limited number of studies, our data indicate that LCn-3 PUFA supplementation has no effect on muscle strength or functional abilities in older adults but may increase muscle mass, although, with only a few studies and considerable heterogeneity, further work is needed to confirm these findings.

The effect of LCn-3 PUFA supplementation on body weight, body composition, and muscle function during alternate-day fasting (ADF)

During weight loss the loss of body mass is associated not only with body fat reduction but also with a decrease in fat-free mass (FFM), related to the reduction in muscle mass and function(1). Supplementation with long-chain n-3 fatty acids (LCn-3 PUFA), in the absence of caloric restriction, results in a significant decrease in fat mass and an increase in FFM(2) along with improvements in muscle mass and strength(3). However, the impact of supplementation with LCn-3 PUFA during weight loss) remains unknown. Therefore, the aim of this study was to explore the effects of LCn-3 PUFA supplementation, in the form of Krill oil (KO), during alternate day fasting (ADF) on body weight, fat mass loss, FFM and muscle function changes in healthy overweight and obese adults.A total of 41 men and women (age: 39.35 ± 10.4 years, BMI: 31.05 ± 4.2 kg/m2) completed the study (NCT06001632), in which they were randomised into either a KO or Placebo (PL) groups. Both groups carried out 8-weeks of ADF combined with intake of 4 g/day of the corresponding supplements. ADF involved consuming no more than 500 calories on the 'fast day’ and consuming food ad libitum on each 'feed day’. Data on body weight and body composition (TBF-300, Tanita, Manchester, UK), handgrip strength (Handheld Hydraulic Dynamometer, Vernier Jamar; England, UK), and time to conduct 5 repetition of chair rising test were obtained pre-and post-intervention. Changes from baseline within groups were assessed using paired samples t-test. Mixed analysis of variance (Mixed-ANOVA) was used to measure 2-way interactions between time and group to identify the differences between groups. All statistical analysis were conducted using IBM Statistical Package for the Social Sciences SPSS 28.0.In both groups, body mass decreased significantly (KO:-4.7 ± 0.4kg, p<0.001; PL:-4.5 ± 0.4kg, p<0.001), along with a significant reduction in fat mass (KO:-2.4 ± 0.5kg p<0.001; PL:-2.3 ± 0.5kg p<0.001), and FFM (KO:-0.6 ± 0.2kg p<0.001; PL:-0.7 ± 0.2kg, p<0.001), with no differences between groups. In the PL group, there was a reduction in handgrip strength (-0.9 ± 0.7 kg, p<0.001), while there was no change in KO group (-0.2 ± 0.5 kg, p=0.1), with a significant difference between groups (p<0.001). In the KO group there was a significant reduction in time to conduct chair rising test (-1.8 ± 0.9s, p<0.05), with no change in the PL group (-0.3 ± 1.3s, p=0.2), with a significant difference between groups (p<0.001).Supplementation with LCn-3 PUFA (4 g/day) during 8 weeks of ADF, applied to individuals living with overweigh and obesity, does not facilitate body or fat mass loss and does not diminish the reduction in FFM. However, it attenuated the reduction in muscle function in healthy overweight and obese adults.

Dietary fats and the APOE-e4 risk allele in relation to cognitive decline: a longitudinal investigation in a biracial population sample

BackgroundAPOE-e4 is the strongest genetic risk factor for Alzheimer's disease. However, the influence of APOE-e4 on dietary fat intake and cognition has not been investigated. ObjectiveWe aim to examine the association of types of dietary fat and their association to cognitive decline among those with and without the APOE-e4 allele. MethodsThe study included 3,360 Chicago Health and Aging Project (CHAP) participants from four Southside Chicago communities. Global cognition was assessed using a composite score of episodic memory, perceptual speed, MMSE, and diet using a 144-item food frequency questionnaire. APOE genotype was assessed by the hME Sequenom mass-array platform. Longitudinal mixed-effect regression models were used to examine the association of dietary fat and the APOE-e4 allele with cognitive decline, adjusted for age, sex, education, smoking status, and calorie intake. ResultsThe present study involved 3,360 participants with a mean age of 74 at baseline, 62% African Americans, 63% females, and a mean follow-up of 7.8 years. Among participants with the APOE-e4 risk allele, higher intakes of total and saturated fat (SFA) were associated with a faster decline in global cognition. Among individuals with the APOE-e4 risk allele, a 5% increase in calories from SFA was associated with a 21% faster decline (β = −0.0197, P = 0.0038). In contrast, a higher intake of long-chain n-3 polyunsaturated fatty acids (LC-n3 PUFA) was associated with a slower rate of decline in global cognition among APOE-e4 carriers. Specifically, for every 1% energy increment from LC-n3 PUFA, the annual rate of global cognitive decline was slower by 0.024 standardized unit (SD 0.010, P = 0.023), about 30.4% slower annual cognitive decline. Higher SFA or other types of dietary fat were not associated with cognitive decline among APOE-e4 non-carriers. ConclusionsOur study found a significant association between SFA and faster cognitive decline, LC-n3 PUFA and slower cognitive decline among those with the APOE-e4 allele. Our findings suggested that higher intake of SFA might contribute faster cognitive decline in combination with APOE-e4 whereas LC-n3 PUFA might compensate the adverse effects of APOE-e4. The interaction between intakes of different types of dietary fat and APOE-e4 on cognitive function warrants further research.

Erythrocyte Long-Chain ω-3 Fatty Acids Are Positively Associated with Lean Mass and Grip Strength in Women with Recent Diagnoses of Breast Cancer.

Sarcopenia may hasten the risk of mortality in women with breast cancer. Long-chain omega-3 (n-3) polyunsaturated fatty acids (LCn-3PUFAs) may favor muscle mass which, in turn, could enhance resilience of cancer patients toward cancer treatment. The objective of this study was to measure the relation of erythrocyte LCn-3PUFA concentrations with lean mass, grip strength, and postprandial energy metabolism in women with newly diagnosed breast cancer. This cross-sectional analysis evaluated women (n=150) ages 65 y and younger who were recently diagnosed with breast cancer (stages I-III). Erythrocyte LCn-3PUFA composition was measured using GC. Body composition was measured by DXA. Grip strength was assessed at the same visit. Postprandial energy metabolism was measured for 7.5 h after the consumption of a high-calorie, high-saturated-fat test meal using indirect calorimetry. Associations of fatty acids with outcomes were analyzed using multiple linear regression models and linear mixed-effects models. The ω-3 index, a measurement of LCn-3PUFA status, was positively associated with appendicular lean mass (ALM)/BMI (β = 0.015, P=0.01) and grip strength (β = 0.757, P=0.04) after adjusting data for age and cancer stage. However, when cardiorespiratory fitness was also included in the analyses, these relations were no longer significant (P>0.08). After a test meal, a higher ω-3 index was associated with a less steep rise in fat oxidation (P=0.02) and a steeper decline in glucose (P=0.01) when adjusting for age, BMI, cancer stage, and cardiorespiratory fitness. The ω-3 index was positively associated with ALM/BMI and grip strength in women newly diagnosed with breast cancer and was associated with altered postprandial substrate metabolism. These findings warrant further studies to determine whether enriching the diet with LCn-3PUFAs during and after cancer treatments is causally linked with better muscle health and metabolic outcomes in breast cancer survivors.

Long-Chain Omega-3 Fatty Acid Intake Is Associated with Age but not Cognitive Performance in an Older Australian Sample.

Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) are essential nutrients and may be capable of delaying age-related cognitive decline. However, previous studies indicate that Australians are not meeting recommendations for LCn-3 PUFA intake. The current study therefore examined LCn-3 PUFA intake in an older Australia sample, as well as associations between LCn-3 PUFA intake and cognitive function. Cross-sectional data were collected from 90 adults aged 50 to 80 years. LCn-3 PUFA intake was assessed using a food frequency questionnaire and red blood cell fatty acid profiles were used to calculate the Omega-3 Index (RBC n-3 index). Cognitive function was measured using Addenbrooke's Cognitive Examination-III. Positive associations were observed between age and RBC n-3 index (b=0.06, 95% CI: 0.01 - 0.10, P=0.01), and age and LCn-3 PUFA intake from fish oil capsules (b=17.5, 95% CI: 2.4 - 32.5 mg/day, P=0.02). When adjusting for LCn-3 PUFA from fish oil capsules, the association between age and RBC n-3 index was no longer significant. No associations were observed between LCn-3 PUFA intake and cognitive function. LCn-3 PUFA and fish oil consumption increased with age in this sample of older Australians, particularly due to supplement intake. However, LCn-3 PUFA intake was not associated with cognitive function.

Fatty acids: a role for Africa?

Health effects of fatty acids have been very controversial. Total mortality is inversely associated with the amount of total fat consumed. In contrast, trans fatty acids or SFA intake is positively related to mortality while the inverse is observed with consumption of MUFA or PUFA. Among PUFA, long-chain (LC) n-3 PUFA have many beneficial effects. Dietary intake of some types of fatty acids is specific to Africa. Energy from saturated fat does not exceed 14% and energy from n-6 PUFA does not exceed 8% of total energy intake. Dietary intake of LC n-3 PUFA is less than 100 mg/d whereas international recommendations promote 250-500 mg/d. Consumption of plant n-3 PUFA mainly α-linolenic acid (ALA) is highly variable depending on the country. Both fish and ALA availability are low in several African countries. The prevalence of diabetes and cardiovascular events remain very low in Africa, partly explained by the fact that the whole dietary pattern is globally the best of all continents. One objective of 'fat for Africa' could be to increase, as much as possible, the dietary intake of LC n-3 PUFA by promoting sustainable aquaculture and to maintain as much as possible traditional dietary pattern by preventing a tendency to westernisation, provided that the amount of energy and protein is sufficient to fight against wasting and stunting where it still exists.

Cold-pressed minke whale oil reduces circulating LDL/VLDL-cholesterol, lipid oxidation and atherogenesis in apolipoprotein E-deficient mice fed a Western-type diet for 13\xa0weeks

BackgroundLong-chain n3-polyunsaturated fatty acids (LC n3-PUFA) are well known for their anti-inflammatory activity and their impact on cardiovascular disease. Cold-pressed whale oil (CWO) has half the amount of LC n3-PUFA compared to cod liver oil (CLO). Still, there has been observed more pronounced beneficial effects on cardiovascular disease markers from intake of CWO compared to intake of CLO in human intervention studies. Extracts from CWO deprived of fatty acids have also been shown to display antioxidative and anti-inflammatory effects in vitro. The aim of this study was to investigate whether intake of a high-fat Western-type diet (WD) supplemented with CWO would prevent the development of atherosclerotic lesions in apolipoprotein E-deficient (ApoE−/−) mice.MethodsSeventy female ApoE−/− mice were fed a WD containing 1% CWO, CLO or corn oil (CO). Atherosclerotic lesion formation, body and tissue weights, hepatic gene expression together with serum levels of LDL/VLDL-cholesterol, ox-LDL, total antioxidant status and various serum cardiovascular disease/proinflammatory markers were evaluated. Statistical analyses were performed using SPSS, and Shapiro-Wilk’s test was performed to determine the distribution of the variables. Statistical difference was assessed using One-Way ANOVA with Tukeys’ post hoc test or Kruskal-Wallis test. The hepatic relative gene expression was analysed with REST 2009 (V2.0.13).ResultsMice fed CWO had less atherosclerotic lesions in the aortic arch compared to mice fed CO. Levels of LDL/VLDL-cholesterol and ox-LDL-cholesterol were also markedly reduced whereas total antioxidant levels were enhanced in mice fed CWO compared to CO-fed mice. In addition, CWO-fed mice gained less weight and several hepatic genes involved in the cholesterol metabolism were up-regulated compared to CO-fed mice.ConclusionIn the present study mice fed a WD supplemented with 1% CWO had reduced formation of atherosclerotic lesions in the aortic arch, reduced serum LDL/VLDL-cholesterol and ox-LDL-cholesterol, increased serum total antioxidant status and reduced body weight compared to mice fed a WD supplemented with 1% CO.

Effects of Long-Chain Omega-3 Polyunsaturated Fatty Acids on Endothelial Vasodilator Function and Cognition-Are They Interrelated?

Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) may improve brain functions by acting on endothelial cells in the cerebrovasculature to facilitate vasodilatation and perfusion. The aim of this review is to explore this hypothesis by analyzing the effect of LCn-3 PUFA supplementation on systemic vasodilator and cognitive function and finding evidence to link LCn-3 PUFA intake, vasodilator function and cognition. Forty randomized controlled trials examining the effect of LCn-3 PUFA supplementation in humans on either endothelial vasodilator function or cognition were identified and pooled effects measured with a weighted analysis. Compared to placebo, LCn-3 PUFA tended to increase flow-mediated dilatation and significantly improved cognitive function. Emerging evidence links vasodilator dysfunction to cognitive impairment, but evidence that LCn-3 PUFA can improve cognition through enhancements of vasodilator function is still lacking. Further research is needed to determine: (1) whether LCn-3 PUFA can enhance dilatation of cerebral vessels; (2) if improvements in cerebrovascular responsiveness by LCn-3 PUFA are accompanied by cognitive benefits; and (3) the target population groups.

Modulation of Ras/ERK and Phosphoinositide Signaling by Long-Chain n-3 PUFA in Breast Cancer and Their Potential Complementary Role in Combination with Targeted Drugs.

A potential complementary role of the dietary long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFA) in combination with innovative mono-targeted therapies has recently been proposed. These compounds are thought to act pleiotropically to prevent the development and progression of a variety of cancers, including breast cancer. We hereinafter critically analyze the reports investigating the ability of LCn-3 PUFA to modulate the Ras/ERK and the phosphoinositide survival signaling pathways often aberrantly activated in breast cancer and representing the main targets of innovative therapies. The in vitro or in vivo animal and human interventional studies published up to January 2017 investigating the effects of LCn-3 PUFA on these pathways in normal and cancerous breast cells or tissues were identified through a systematic search of literature in the PubMed database. We found that, in most cases, both the in vitro and in vivo studies demonstrated the ability of LCn-3 PUFA to inhibit the activation of these pro-survival pathways. Altogether, the analyzed results strongly suggest a potential role of LCn-3 PUFA as complementary agents in combination with mono-targeted therapies. Moreover, the results indicate the need for further in vitro and human interventional studies designed to unequivocally prove the potential adjuvant role of these fatty acids.

Pattern of omega-3 polyunsaturated fatty acid intake and fish consumption and retinal vascular caliber in children and adolescents: A cohort study

We aimed to investigate whether fish and long chain omega-3 polyunsaturated fatty acid (LCn-3 PUFA) consumption changed appreciably during adolescence. We also assessed whether these dietary variables are associated with retinal microvascular signs (possible markers of future cardiovascular disease risk). 633 children had dietary data at ages 12 and 17. Fish and LCn-3 PUFA [eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA)] intake was assessed by a food frequency questionnaire. Retinal vessel caliber was quantified from digital photographs using computer software. Mean energy-adjusted intakes (mg/day) of total LCn-3 PUFA, EPA, and DHA at age 12 were 297.1±261.1; 102.5±106.9; and 129.7±137.7, respectively; and this increased significantly at age 17 to: 347.0±324.0 (p<0.0001); 122.5±132.7 (p = 0.0001); and 160.3±171.4 (p <0.0001), respectively. Increasing quartiles of LCn-3PUFA intake were associated with widening of mean retinal arteriolar caliber among 17-year old girls ~3.9 μm (multivariable-adjusted P-trend = 0.001). Girls who consumed ≥2 serves of fish/week versus those who did not had ~2.1 μm wider retinal arterioles (p = 0.03). No associations were observed among boys or with retinal venules. Mean dietary intakes of LCn-3 PUFA increased during adolescence, but are still below recommended levels of consumption. These results suggest that LCn-3 PUFA and fish intake might have a beneficial influence.

Why are fish oil supplements apparently failing to reproduce fish consumption epidemiology in RCT for cardiovascular disease?

Why are fish oil supplements apparently failing to reproduce fish consumption epidemiology in RCT for cardiovascular disease?

Up-Regulation of Mitochondrial Antioxidant Superoxide Dismutase Underpins Persistent Cardiac Nutritional-Preconditioning by Long Chain n-3 Polyunsaturated Fatty Acids in the Rat.

Reactive oxygen species paradoxically underpin both ischaemia/reperfusion (I/R) damage and ischaemic preconditioning (IPC) cardioprotection. Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) are highly susceptible to peroxidation, but are paradoxically cardioprotective. This study tested the hypothesis that LCn-3 PUFA cardioprotection is underpinned by peroxidation, upregulating antioxidant activity to reduce I/R-induced lipid oxidation, and the mechanisms of this nutritional preconditioning contrast to mechanisms of IPC. Rats were fed: fish oil (LCn-3 PUFA); sunflower seed oil (n-6 PUFA); or beef tallow (saturated fat, SF) enriched diets for six weeks. Isolated hearts were subject to: 180 min normoxic perfusion; a 30 min coronary occlusion ischaemia protocol then 120 min normoxic reperfusion; or a 3 × 5 min global IPC protocol, 30 min ischaemia, then reperfusion. Dietary LCn-3 PUFA raised basal: membrane docosahexaenoic acid (22:6n-3 DHA); fatty acid peroxidisability index; concentrations of lipid oxidation products; and superoxide dismutase (MnSOD) activity (but not CuZnSOD or glutathione peroxidase). Infarct size correlated inversely with basal MnSOD activity (r2 = 0.85) in the ischaemia protocol and positively with I/R-induced lipid oxidation (lipid hydroperoxides (LPO), r2 = 0.475; malondialdehyde (MDA), r2 = 0.583) across ischaemia and IPC protocols. While both dietary fish oil and IPC infarct-reduction were associated with reduced I/R-induced lipid oxidation, fish oil produced nutritional preconditioning by prior LCn-3 PUFA incorporation and increased peroxidisability leading to up-regulated mitochondrial SOD antioxidant activity.

Cancer Risk and Eicosanoid Production: Interaction between the Protective Effect of Long Chain Omega-3 Polyunsaturated Fatty Acid Intake and Genotype.

Dietary inclusion of fish and fish supplements as a means to improve cancer prognosis and prevent tumour growth is largely controversial. Long chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA), eicosapentaenoic acid and docosahexaenoic acid, may modulate the production of inflammatory eicosanoids, thereby influencing local inflammatory status, which is important in cancer development. Although in vitro studies have demonstrated inhibition of tumour cell growth and proliferation by LCn-3 PUFA, results from human studies have been mainly inconsistent. Genes involved in the desaturation of fatty acids, as well as the genes encoding enzymes responsible for eicosanoid production, are known to be implicated in tumour development. This review discusses the current evidence for an interaction between genetic polymorphisms and dietary LCn-3 PUFA in the risk for breast, prostate and colorectal cancers, in regards to inflammation and eicosanoid synthesis.

Suboptimal Plasma Long Chain n-3 Concentrations are Common among Adults in the United States, NHANES 2003-2004.

Population data on long-chain omega-3 polyunsaturated fatty acid (LCn-3 PUFA) status from biomarkers of dietary intake is lacking. The objectives were to describe plasma LCn-3 PUFA concentrations and compare them to concentrations associated with cardiovascular health and dietary recommendations for two servings of seafood/week. Fasting plasma fatty acids were measured among 1386 subjects ≥20 years from the National Health and Nutrition Examination Survey, 2003–2004. LCn-3 concentrations represent the sum of eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid relative to total fatty acids (expressed as a percentage). Mean LCn-3 PUFA concentration was 2.07% (95% CI 1.95–2.19). Overall, 80.6% of participants had LCn-3 below concentrations recommended for cardiovascular health. Hispanic participants were the most likely to have LCn-3 PUFA below recommended levels. Nearly all participants (95.7%) had LCn-3 below concentrations associated with cardiovascular protection. Older participants (≥60 years) had higher LCn-3 PUFA concentrations than those aged 20–39 years but not aged 40–59 years. LCn-3 PUFA concentrations were lower for Hispanic participants relative to non-Hispanic black participants. Suboptimal LCn-3 concentrations are common among U.S. adults. These findings highlight the need to increase LCn-3 intake among Americans.

Low dose fish oil increases the omega-3 index improving cycling efficiency and heart rate recovery

Background: Dietary fish oil provides long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The heart (Charnock et al., 1986: Annals of Nutrition and Metabolism, 30, 393-406) and skeletal muscle (Peoples & McLennan, 2010: British Journal of Nutrition, 104(12), 1771-1779) preferentially incorporate DHA and modulates both myocardial (Pepe & McLennan, 2002: Circulation, 105, 2303-2308) and skeletal muscle oxygen consumption translated as improved muscle fatigue resistance (Peoples & McLennan, 2014: British Journal of Nutrition, 111, 996-1004). However, studies of well-trained endurance athletes have used excessive doses of DHA (Peoples et al., 2008: Journal of Cardiovascular Pharmacology, 52, 540-547;  Buckley et al., 2009: Journal of Science and Medicine in Sport, 12(4), 503-507). Given that even a very low fish oil supplement maximises membrane incorporation of DHA (Slee et al., 2010: Journal of Lipid Research, 51, 1841-1847) there is strong physiological basis for cyclists to improve oxygen efficiency through a nutritional approach. Purpose: The current study primarily aimed to establish if provision of a low dose of dietary fish oil in cyclists could convey improved oxygen efficiency in heart and skeletal muscle under conditions of established cycling fatigue and acute recovery. Methods: Using a double-blind design, trained males (N=26) were supplemented with (2x1g.d-1) soy oil (control n=13) or tuna fish oil (FO n=13) providing LCn-3PUFA, DHA: 560mg and EPA: 140mg (Nu-Mega, Australia) for 8 weeks. Erythrocyte omega-3 index (% EPA+DHA) was measured at baseline at following supplementation. At both time points participants underwent a repeated Wingate cycling protocol (6x30sec / 150seconds recovery) to establish cycling fatigue, immediately followed by a 5min cycling time trial (Wattbike, UK). Upon completion, participants were place in a supine recovery position for 10mins. Oxygen consumption (O2), heart rate (HR) and power (W) were continuously monitored.Results: Erythrocyte omega-3 index at baseline (Control: 4.2±0.2; FO: 4.7±0.2%) was not different between groups. After 8weeks the omega-3 index was unchanged in control (3.9±0.2%) but increased in FO group (6.3±0.3%, P< 0.01). There was no effect of FO supplementation on; peak HR (Control: 174±1 FO: 176±1beats.min-1), mean power during Wingate cycling fatigue protocol (Control: 545±28; FO: 511±33W), or cycling time trial performance under established fatigue (Control: 267±19; FO: 253±16W). However, FO supplementation improved oxygen efficiency (delta change) during the cycling time trial (Control: -23±26; FO: -154±59ml O2/min/100W P<0.05) and accelerated HR recovery (logit half-time) in the supine position immediately afterwards (Control: -0.4±1.2s; FO: -8.0±1.7s, P<0.05). The later was independent of a change in parasympathetic tone and reflective of reduced myocardial oxygen consumption.Discussion: A low dose fish oil supplement providing DHA increased the omega-3 index in trained cyclists. The improved cycling efficiency is reflective of the oxygen modulation previously demonstrated in rodent skeletal muscle (Peoples & McLennan, 2014), while the faster heart rate recovery without alteration in autonomic tone is supportive of the a reduction in intrinsic beat rate of the SA node following DHA administration (Verkerk, et al., 2009: Heart Rhythm, 6(10), 1485-1492). Conclusion: Provision of LCn-3 PUFA, DHA, in the form of a low dose fish oil supplement can have profound effects on heart and skeletal muscle incorporation, and as consequence improve cycling efficiency and heart rate recovery, indicative of reduced heart load. As a consequence, the concentrations used in the current study can be modeled for nutritional recommendations of DHA in elite cyclists.

Opportunities to enhance alternative sources of long-chain n-3 fatty acids within the diet.

Health benefits or advocated health benefits of long-chain (LC) n-3 PUFA are better known by medical doctors as well as by consumers, so that consumption increases. In addition, the development of aquaculture requires more fishmeal and fish oil. Humanisation of care of companion animals is also associated with addition of LC n-3 PUFA in pet foods. The risk of the increased demand for LC n-3 PUFA is the excess harvesting of natural sources, especially of marine origin (oily fishes, krill). In order to improve sustainability, alternative sources of LC n-3 PUFA have been developed. These alternative sources are: (a) terrestrial plants naturally or genetically enriched in stearidonic acid (SDA), which bypasses the first limiting step of (i.e. ∆6 desaturase) of the biosynthesis of LC n-3 PUFA; (b) single-cell oils rich in LC n-3 PUFA (microalgae, Escherichia coli) and krill. Currently, plants rich in SDA are expensive, metabolic engineering is unfavourably accepted by consumers in many countries, cultivation of microalgae is very expensive even though their ability (for some of them) to synthesise biofuels could induce a decrease in industrial costs, and Antarctic krill harvest must be restricted. Thus, it is difficult to predict their real development in the future.

Validity of food frequency questionnaire-based estimates of long-term long-chain n-3 polyunsaturated fatty acid intake

To evaluate how long-term dietary intake of long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFAs), estimated by repeated food frequency questionnaires (FFQs) over 15 years, is correlated with LCn-3 PUFAs in adipose tissue (AT). Subcutaneous adipose tissue was obtained in 2003-2004 (AT-03) from 239 randomly selected women, aged 55-75 years, after completion of a 96-item FFQ (FFQ-03). All participants had previously returned an identical FFQ in 1997 (FFQ-97) and a 67-item version in 1987-1990 (FFQ-87). Pearson product-moment correlations were used to evaluate associations between intake of total and individual LCn-3 PUFAs as estimated by the three FFQ assessments and AT-03 content (% of total fatty acids). FFQ-estimated mean relative intake of LCn-3 PUFAs (% of total fat intake) increased between all three assessments (FFQ-87, 0.55 ± 0.34; FFQ-97, 0.74 ± 0.64; FFQ-03, 0.88 ± 0.56). Validity, in terms of Pearson correlations between FFQ-03 estimates and AT-03 content, was 0.41 (95% CI 0.30-0.51) for total LCn-3 PUFA and ranged from 0.29 to 0.48 for individual fatty acids; lower correlation was observed among participants with higher percentage body fat. With regard to long-term intake estimates, past dietary intake was also correlated with AT-03 content, with correlation coefficients in the range of 0.21-0.33 and 0.21-0.34 for FFQ-97 and FFQ-87, respectively. The correlations were improved by using average estimates from two or more FFQ assessments. Exclusion of fish oil supplement users (14%) did not alter the correlations. These data indicate reasonable validity of FFQ-based estimates of long-term (up to 15 years) LCn-3 PUFA intake, justifying their use in studies of diet-disease associations.

Health impacts of eicosapentaenoic acid and docosahexaenoic acid.

Abstract Long chain omega-3 polyunsaturated fatty acids (LC n -3 PUFA) particularly, eicosapentaenoic acid (EPA, 22: 5 n -3) and docosahexaenoic acid (DHA, 22: 6 n -3) have been reported to reduce the risks of cardiovascular disease (CVD) including myocardial infarction, stroke, coronary artery disease and sudden cardiac death. In addition, these fatty acids play an important role in reduction of cancer risks, Alzheimer's disease, depression and schizophrenia. Furthermore, studies also showed that EPA and DHA are important for foetal development, particularly neuronal and retinal functions. Several recent human trials have strengthened the evidence that EPA and DHA can reduce the risks of various chronic diseases although this has not been a uniform finding. In general, the high prevalence of mortality caused by chronic disease can be prevented by consumption of LC n -3 PUFA, which has been proven to have considerable health benefits. The aim of this paper was to review main scientific evidence regarding the health impact of LC n -3 PUFA, especially EPA and DHA on chronic disease including CVD, cancer, mental health, arthritis and infant development.

Similarities and differences between the effects of EPA and DHA on markers of atherosclerosis in human subjects

We have reviewed effects of long chain (LC) n-3 PUFA on markers of atherosclerosis in human subjects with a focus on individual effects of EPA and DHA. Initial results from epidemiological studies suggested that LC n-3 PUFA from fish oils (FO) reduced incidence of CVD; those results have been confirmed in interventional studies. Dietary intervention with n-3 PUFA decreased fasting and postprandial TAG, number of remnant-like chylomicron particles, large VLDL, and total and small dense LDL particles. It increased mean size of LDL particles by increasing number of large and decreasing those of small dense particles. With some exceptions, n-3 PUFA decreased blood pressure (BP) and heart rate (HR), flow-mediated dilation (FMD) and plasma concentrations of inflammatory markers. n-3 PUFA also decreased circulating adhesion molecules and intima-media thickness (IMT) in some but not other studies. For IMT, results varied with the sex and artery being examined. EPA effects on FMD are endothelial cell dependent, while those of DHA seem to be endothelial cell independent. Individually, both EPA and DHA decreased TAG and inflammatory markers, but only DHA decreased HR, BP and number of small dense LDL particles. Results varied because of dose and duration of n-3 PUFA, EPA:DHA, health status of subjects and other reasons. Future studies are needed to determine optimal doses of EPA and DHA individually, their synergistic, additive or antagonistic effects, and to understand underlying mechanisms. In conclusion, n-3 PUFA decreased several risk factors for atherosclerosis without any serious adverse effects.