Dietary alpha-linolenic acid, EPA, and DHA have differential effects on LDL fatty acid composition but similar effects on serum lipid profiles in normolipidemic humans

Cardiovascular risk protection from the Mediterranean diet and olive oil. A transcriptomic update in humans

This review highlights the human studies that explore the benefits of the Mediterranean diet and olive oil, based on gene expression analysis. We summarized consistent human transcriptomic studies on cardiovascular risk, based on TMD and olive oil interventions, with real life doses and conditions. A literature review was carried out leading up to February 2016. The results show that the TMD, specially supplemented with virgin olive oil, produces beneficial changes in the transcriptomic response of relevant genes in cardiovascular risk such as CAT, GPX1 and SIRT2. p65 and MCP-1, IL1B, IL6, CXCL1, INF-γ, ARHGAP15 and IL7R, which are involved in inflammation; and ABCA1, SR-B1, PPARBP, PPARα, PPARγ, PPARδ, CD-36 and COX-1, which play an important role in cholesterol efflux. The available data illustrate a transcriptomic effect on atherosclerosis, inflammation and oxidative stress pathways as well as the mentioned genes.

Effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular disease risk factors: a randomized clinical trial

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the primary omega-3 fatty acids in fish oil, have been shown to reduce cardiovascular disease (CVD) risk.

OBJECTIVE

This study aimed to examine the independent effects of EPA and DHA on lipid and apolipoprotein levels, as well as on inflammatory biomarkers of CVD risk, using doses often used in the general population.

DESIGN

A blinded, randomized 6-week trial was performed in 121 healthy, normolipidemic subjects who received olive oil placebo 6g/d, EPA 600mg/d, EPA 1800mg/d, or DHA 600mg/d. The EPA was derived from genetically modified yeast.

RESULTS

The subjects tolerated the supplements well with no safety issues; and the expected treatment-specific increases in plasma EPA and DHA levels were observed. Compared to placebo, the DHA group had significant decreases in postprandial triglyceride (TG) concentrations (-20%, -52.2mg/dL, P=0.03), significant increases in fasting and postprandial low-density lipoprotein cholesterol (LDL-C) (+18.4%, 17.1mg/dL, P=0.001), with no significant changes in inflammatory biomarkers. No significant effects were observed in the EPA 600mg/d group. The high-dose EPA group had significant decreases in lipoprotein-associated phospholipase A2 concentrations (Lp-PLA₂) (-14.1%, -21.4ng/mL, P=0.003).

CONCLUSIONS

The beneficial effects of EPA 1800mg/d on CVD risk reduction may relate in part to the lowering of Lp-PLA₂ without adversely affecting LDL-C. In contrast, DHA decreased postprandial TG, but raised LDL-C. Our observations indicate that these dietary fatty acids have divergent effects on cardiovascular risk markers.

Comparative anti-inflammatory and lipid-normalizing effects of metformin and omega-3 fatty acids through modulation of transcription factors in diabetic rats

BACKGROUND

Emerging evidence suggests beneficial effects of omega-3 fatty acids on diabetic complications. The present study compared the progressive effects of metformin and flax/fish oil on lipid metabolism, inflammatory markers, and liver and renal function test markers in streptozotocin-nicotinamide-induced diabetic rats.

METHODS

Streptozotocin-induced diabetic rats were randomized into control and four diabetic groups: streptozotocin (STZ), metformin (200 mg/kg body weight (b.w)/day (D)), flax and fish oil (500 mg/kg b.w/D).

RESULTS

Metformin and flax and fish oil exhibited increased expression of transcription factor peroxisome proliferator-activated receptor γ while the treatment downregulated sterol regulatory element-binding protein 1 and nuclear factor kβ as compared to those of the STZ group. Apart from modulation of transcription factor expression, the expression of fatty acid synthase, long chain acyl CoA synthase, and malonyl-CoA-acyl carrier protein transacylase was lowered by flax/fish oil treatment. Serum cholesterol, triglycerides, and VLDL were also significantly reduced in the treatment groups as compared to those in the STZ group. Although pathological abnormalities were seen in the liver and kidneys of rats on metformin, no significant changes in liver/renal function markers were observed at day 15 and day 30 of the treatment groups. Flax/fish oil had protective effects toward pathological abnormalities in the liver and kidney. Flax/fish oil improved lipid profile and alkaline phosphatase at day 30 as compared to that at day 15.

CONCLUSIONS

The present study demonstrates potential beneficial effects of metformin and flax/fish oil intervention in improving serum lipid profile by regulating the expression of transcription factors and genes involved in lipid metabolism in diabetic rats. In addition, these interventions also lowered the expression of atherogenic cytokines. The protective effects of flax/fish oil are worth investigating in human subjects on metformin monotherapy.

A Contribution of Beef to Human Health: A Review of the Role of the Animal Production Systems

Meat and meat products constitute important source of protein, fat, and several functional compounds. Although beef consumption may implicate possible negative impacts on human health, its consumption can also contribute to human health. Quality traits of beef, as well as its nutritional properties, depend on animal genetics, feeding, livestock practices, and post mortem procedures. Available data show that emerging beef production systems are able to improve both, quality and nutritional traits of beef in a sustainable way. In this context, Argentina's actions are aimed at maximising beef beneficial effects and minimising its negative impact on human health, in a way of contributing to global food security.

A Transgenic Camelina sativa Seed Oil Effectively Replaces Fish Oil as a Dietary Source of Eicosapentaenoic Acid in Mice

BACKGROUND

Fish currently supplies only 40% of the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) required to allow all individuals globally to meet the minimum intake recommendation of 500 mg/d. Therefore, alternative sustainable sources are needed.

OBJECTIVE

The main objective was to investigate the ability of genetically engineered Camelina sativa (20% EPA) oil (CO) to enrich tissue EPA and DHA relative to an EPA-rich fish oil (FO) in mammals.

METHODS

Six-week-old male C57BL/6J mice were fed for 10 wk either a palm oil-containing control (C) diet or diets supplemented with EPA-CO or FO, with the C, low-EPA CO (COL), high-EPA CO (COH), low-EPA FO (FOL), and high-EPA FO (FOH) diets providing 0, 0.4, 3.4, 0.3, and 2.9 g EPA/kg diet, respectively. Liver, muscle, and brain were collected for fatty acid analysis, and blood glucose and serum lipids were quantified. The expression of selected hepatic genes involved in EPA and DHA biosynthesis and in modulating their cellular impact was determined.

RESULTS

The oils were well tolerated, with significantly greater weight gain in the COH and FOH groups relative to the C group (P < 0.001). Significantly lower (36-38%) blood glucose concentrations were evident in the FOH and COH mice relative to C mice (P < 0.01). Hepatic EPA concentrations were higher in all EPA groups relative to the C group (P < 0.001), with concentrations of 0.0, 0.4, 2.9, 0.2, and 3.6 g/100 g liver total lipids in the C, COL, COH, FOL, and FOH groups, respectively. Comparable dose-independent enrichments of liver DHA were observed in mice fed CO and FO diets (P < 0.001). Relative to the C group, lower fatty acid desaturase 1 (Fads1) expression (P < 0.005) was observed in the COH and FOH groups. Higher fatty acid desaturase 2 (Fads2), peroxisome proliferator-activated receptor α (Ppara), and peroxisome proliferator-activated receptor γ (Pparg) (P < 0.005) expressions were induced by CO. No impact of treatment on liver X receptor α (Lxra) or sterol regulatory element-binding protein 1c (Srebp1c) was evident.

CONCLUSIONS

Oil from transgenic Camelina is a bioavailable source of EPA in mice. These data provide support for the future assessment of this oil in a human feeding trial.

Predictive associations between serum fatty acids and lipoproteins in healthy non-obese Norwegians: implications for cardiovascular health

A battery of methods for multivariate data analysis has been used to assess the associations between concentrations of fatty acids (FAs) and lipoprotein subclasses and particle size in serum for a normolipidemic population of ethnic Norwegians living in the rural Fjord region. Significant gender differences were found in the lipoprotein and FA patterns. Predictive FA patterns were revealed for lipoprotein features of importance for cardiovascular (CV) health. Thus, the subclasses of atherogenic small and very small low density lipoprotein (LDL) particles and the same subclasses of high density lipoprotein (HDL) particles were associated with a pattern of saturated FAs and mono-unsaturated C16-C18 FAs. Eicosapentaenoic acid (EPA) and the ratio of EPA to arachidonic acid (AA) had strongest associations to features that promotes CV health: (i) large average size of HDL and LDL particles, and, (ii) small average size of very low density lipoprotein (VLDL) particles. Total concentration of HDL in both genders correlated to EPA, but docosahexaenoic acid (DHA) correlated just as strongly for women. For men, docosapentaenoic acid (DPA) showed stronger association to HDL concentration than EPA. For both genders, concentration of large LDL particles showed associations to levels of EPA, but stronger to DHA and DPA. High values of EPA/AA seem to be the strongest single biomarker for good CV health in both men and women.

Evidence-Based Guideline of the German Nutrition Society: Fat Intake and Prevention of Selected Nutrition-Related Diseases

As nutrition-related chronic diseases have become more and more frequent, the importance of dietary prevention has also increased. Dietary fat plays a major role in human nutrition, and modification of fat and/or fatty acid intake could have a preventive potential. The aim of the guideline of the German Nutrition Society (DGE) was to systematically evaluate the evidence for the prevention of the widespread diseases obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease (CHD), stroke, and cancer through the intake of fat or fatty acids. The main results can be summarized as follows: it was concluded with convincing evidence that a reduced intake of total and saturated fat as well as a larger intake of polyunsaturated fatty acids (PUFA) at the expense of saturated fatty acids (SFA) reduces the concentration of total and low-density lipoprotein cholesterol in plasma. Furthermore, there is convincing evidence that a high intake of trans fatty acids increases risk of dyslipoproteinaemia and that a high intake of long-chain polyunsaturated n-3 fatty acids reduces the triglyceride concentration in plasma. A high fat intake increases the risk of obesity with probable evidence when total energy intake is not controlled for (ad libitum diet). When energy intake is controlled for, there is probable evidence for no association between fat intake and risk of obesity. A larger intake of PUFA at the expense of SFA reduces risk of CHD with probable evidence. Furthermore, there is probable evidence that a high intake of long-chain polyunsaturated n-3 fatty acids reduces risk of hypertension and CHD. With probable evidence, a high trans fatty acid intake increases risk of CHD. The practical consequences for current dietary recommendations are described at the end of this article.

Association between omega-3 index and blood lipids in older Australians

Management of hyperlipidaemia remains a cornerstone therapy for the prevention of cardiovascular disease (CVD). Dietary supplementation with n-3 polyunsaturated fatty acid (PUFA) has been shown to modulate blood lipid profiles and reduce the risk of developing CVD. However, studies relating objective measures of long-term dietary n-3 PUFA intake and circulating lipid levels in older adults are limited. Thus, we aimed to determine whether there is an association between erythrocyte n-3 PUFA status (omega-3 index, O3I) and blood lipid profiles in older adults. A sample of adults aged 65-95 years who participated in the Retirement Health and Lifestyle Study was evaluated. Outcome measures included O3I (% eicosapentaenoic acid+% docosahexaenoic acid) and fasting blood lipid profiles [total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglyceride (TG)]. Two hundred and seventy-six subjects were included in the analyses. The mean±SD age was 77.6±7.4 years, and 40.9% were males. O3I was significantly higher in females compared to males. O3I was inversely associated with plasma TG (P<.001) and TC/HDL-cholesterol ratio (P<.05), and positively associated with HDL-cholesterol (P<.05), in all subjects. Associations between O3I and TG were evident in both females (r=-0.250, P<.01) and males (r=-0.225, P<.05). In females only, the odds of being hypertriglyceridaemic were highest in those with lowest O3I (P=.006). Trends for hypercholesterolaemia and elevated LDL risk were converse between males and females. Long-term n-3 PUFA status is associated with blood lipid profiles in older Australians. Our findings support the development and implementation of age-specific dietary strategies to reduce the risk of CVD via improving the O3I.

Functional Roles of Fatty Acids and Their Effects on Human Health

A variety of fatty acids exists in the diet of humans, in the bloodstream of humans, and in cells and tissues of humans. Fatty acids are energy sources and membrane constituents. They have biological activities that act to influence cell and tissue metabolism, function, and responsiveness to hormonal and other signals. The biological activities may be grouped as regulation of membrane structure and function; regulation of intracellular signaling pathways, transcription factor activity, and gene expression; and regulation of the production of bioactive lipid mediators. Through these effects, fatty acids influence health, well-being, and disease risk. The effects of saturated, cis monounsaturated, ω-6 and ω-3 polyunsaturated, and trans fatty acids are discussed. Although traditionally most interest in the health impact of fatty acids related to cardiovascular disease, it is now clear that fatty acids influence a range of other diseases, including metabolic diseases such as type 2 diabetes, inflammatory diseases, and cancer. Scientists, regulators, and communicators have described the biological effects and the health impacts of fatty acids according to fatty acid class. However, it is now obvious that within any fatty acid class, different members have different actions and effects. Thus, it would seem more appropriate to describe biological effects and health impacts of individual named fatty acids, although it is recognized that this would be a challenge when communicating outside of an academic environment (eg, to consumers).

Emerging nutrition science on fatty acids and cardiovascular disease: nutritionists' perspectives

Recent dietary guidance for heart health recommends a reduction (by ∼50%) in saturated fatty acid (SFA) intake to reduce LDL cholesterol and to decrease risk of cardiovascular disease (CVD). The 2010 Dietary Guidelines for Americans recommends substituting unsaturated fat [both polyunsaturated and monounsaturated fatty acids (PUFAs and MUFAs, respectively)] for SFAs. There are many dietary options that can be implemented to replace SFAs, given the different sources of unsaturated fats in the food supply. Compelling evidence exists for the cardioprotective benefits of n-3 (ω-3) PUFAs, both marine- and plant-derived. In addition, the evidence of cardioprotective benefits of n-6 (ω-6) PUFAs is strong, whereas that for MUFAs is mixed, although there is emerging evidence of benefits. Quantitatively, lowering SFAs by 50% will require, in part, substituting food sources of n-6 and n-3 PUFAs and MUFAs for food sources of SFAs. The use of n-3 PUFAs as a replacement for SFAs will result in a shortfall in reaching the SFA goal because of the relatively low amounts that can be incorporated in the diet, even with very high n-3 PUFA substitution. SFAs also can be replaced with dietary carbohydrate and/or protein. Replacing SFAs with carbohydrate, specifically refined sources, however, has little impact on reducing CVD risk. There is evidence about the health benefits of dietary protein on CVD risk, which merits study. Dietary guidelines have advanced considerably with the "replacement of SFA with unsaturated fat message" instead of recommending decreasing SFAs alone. A key question that remains is what is the optimal mix of macronutrients to maximally reduce CVD risk.

The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: a systematic review and commentary

This paper presents a systematic review of human studies investigating the effect of altering dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) alpha-linolenic acid (ALA) and omega-6 polyunsaturated fatty acid (n-6 PUFA) linoleic acid (LA) intakes on n-3 long-chain polyunsaturated fatty acid (LCPUFA) status in adult humans. The results suggest that it is possible to increase n-3 LCPUFA status by reducing LA and/or increasing ALA intake in humans, although decreasing LA intake to below 2.5%E may be required to specifically increase levels of the n-3 LCPUFA docosahexaenoic acid (DHA). The majority of studies in this area to date have been relatively poor in quality, which limits the ability to draw robust conclusions, and we present a series of recommendations to improve the quality of future studies in fatty acid nutrition in humans.

The effect of flaxseed dose on circulating concentrations of alpha-linolenic acid and secoisolariciresinol diglucoside derived enterolignans in young, healthy adults

PURPOSE

The primary endpoint was to determine the plasma concentration of alpha-linolenic acid (ALA), and its metabolites, following milled flaxseed consumption at four doses. Secondary outcomes focused on plasma enterolignan concentrations and the effects on tolerability, platelet aggregation, plasma lipids and urinary thromboxane levels.

METHODS

Healthy, younger adults (n = 34; 18-49 years old) were randomized into four groups consuming one muffin daily for 30 days fortified with 10, 20, 30 or 40 g of milled flaxseed. Blood and urine were collected at baseline and 4 weeks.

RESULTS

Plasma ALA concentrations increased with all flaxseed doses (P < 0.01), except the 20 g/day dose (P = 0.10), yet there was no significant dose-dependent response (P = 0.81). Only with the 30 g/day diet were n-3 polyunsaturated fatty acids (P = 0.007), and eicosapentaenoic acid (EPA) (P = 0.047) increased from baseline values. Docosapentaenoic acid and docosahexaenoic acid were not detected at any dose. Plasma total enterolignan concentrations significantly increased over time in all treatment groups, yet despite a dose-dependent tendency, no between-group differences were detected (P = 0.22). Flaxseed was well tolerated, even at the highest dose, as there were no reported adverse events, changes in cholesterol, platelet aggregation or urinary 11-dehydro-thromboxane B2.

CONCLUSIONS

In healthy, younger adults, 10 g/day of milled flaxseed consumption is sufficient to significantly increase circulating ALA and total enterolignan concentrations; however, 30 g/day is required to convert ALA to EPA. Although all doses were well tolerated, 40 g/day is too low to attenuate cholesterol in this population.

Effects of α-lipoic acid and eicosapentaenoic acid in overweight and obese women during weight loss

OBJECTIVE

To evaluate the potential body weight-lowering effects of dietary supplementation with eicosapentaenoic acid (EPA) and α-lipoic acid separately or combined in healthy overweight/obese women following a hypocaloric diet.

METHODS

This is a short-term double-blind placebo-controlled study with parallel design that lasted 10 weeks. Of the randomized participants, 97 women received the allocated treatment [Control, EPA (1.3 g/d), α-lipoic acid (0.3 g/d), and EPA+α-lipoic acid (1.3 g/d+0.3 g/d)], and 77 volunteers completed the study. All groups followed an energy-restricted diet of 30% less than total energy expenditure. Body weight, anthropometric measurements, body composition, resting energy expenditure, blood pressure, serum glucose, and insulin and lipid profile, as well as leptin and ghrelin levels, were assessed at baseline and after nutritional intervention.

RESULTS

Body weight loss was significantly higher (P<0.05) in those groups supplemented with α-lipoic acid. EPA supplementation significantly attenuated (P<0.001) the decrease in leptin levels that occurs during weight loss. Body weight loss improved lipid and glucose metabolism parameters but without significant differences between groups.

CONCLUSIONS

The intervention suggests that α-lipoic acid supplementation alone or in combination with EPA may help to promote body weight loss in healthy overweight/obese women following energy-restricted diets.

Dietary rapeseed/canola-oil supplementation reduces serum lipids and liver enzymes and alters postprandial inflammatory responses in adipose tissue compared to olive-oil supplementation in obese men

SCOPE

Obesity is associated with hyperlipidemia, hepatic steatosis, and low-grade inflammation. Studies have shown that MUFA as well as PUFA have beneficial effects on blood lipids and the inflammatory state.

METHODS AND RESULTS

This study investigates the effects of a daily supplementation of either 50 g of rapeseed/canola (RA) or olive (OL) oil over 4 wk on serum lipids, serum liver enzymes, and inflammatory gene expression in subcutaneous (s. c.) adipose tissue in obese men. Consuming RA resulted in increased serum n-3 fatty acids and a reduction in total cholesterol, LDL cholesterol, and serum aspartate aminotransferase compared to OL. In s. c. adipose tissue, gene expression of the pro-inflammatory cytokine IL6 was reduced in RA compared to OL. However, after 4 h after a test meal, containing the appropriate oil, white bread, and 400 mL of liquid diet drink (835 kcal in total), gene expression of IL6, IL1B, and EMR1 (egf-like module containing Mucin-like hormone receptor-like 1) was increased in RA and of monocyte chemoattractant protein-1 (CCL2) in both RA and OL.

CONCLUSION

This demonstrates that consuming RA for 4 wk improves serum lipids, liver enzymes, and basal inflammation in s. c. adipose tissue, but it mediates an acute pro-inflammatory response in adipose tissue upon consuming a meal.

The evidence for α-linolenic acid and cardiovascular disease benefits: Comparisons with eicosapentaenoic acid and docosahexaenoic acid

Our understanding of the cardiovascular disease (CVD) benefits of α-linolenic acid (ALA, 18:3n-3) has advanced markedly during the past decade. It is now evident that ALA benefits CVD risk. The expansion of the ALA evidence base has occurred in parallel with ongoing research on eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) and CVD. The available evidence enables comparisons to be made for ALA vs. EPA + DHA for CVD risk reduction. The epidemiologic evidence suggests comparable benefits of plant-based and marine-derived n-3 (omega-3) PUFAs. The clinical trial evidence for ALA is not as extensive; however, there have been CVD event benefits reported. Those that have been reported for EPA + DHA are stronger because only EPA + DHA differed between the treatment and control groups, whereas in the ALA studies there were diet differences beyond ALA between the treatment and control groups. Despite this, the evidence suggests many comparable CVD benefits of ALA vs. EPA + DHA. Thus, we believe that it is time to revisit what the contemporary dietary recommendation should be for ALA to decrease the risk of CVD. Our perspective is that increasing dietary ALA will decrease CVD risk; however, randomized controlled clinical trials are necessary to confirm this and to determine what the recommendation should be. With a stronger evidence base, the nutrition community will be better positioned to revise the dietary recommendation for ALA for CVD risk reduction.

The role of n - 6 and n - 3 polyunsaturated fatty acids in the manifestation of the metabolic syndrome in cardiovascular disease and non-alcoholic fatty liver disease

Cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD) are manifestations of the metabolic syndrome. CVD remains the number one cause of mortality in the West, while NAFLD is the most common liver disease. Growing evidence suggests that polyunsaturated fatty acids (PUFA) influence risk factors including circulating lipids and inflammation on the development of CVD and NAFLD. N - 6 and n - 3 PUFA are comprised of distinct family members, which are increasingly recognized for their individual effects. Therefore, this review examines what is currently known about the specific effects of the major n - 3 and n - 6 PUFA on CVD and NAFLD. Overall, this review supports a beneficial effect of n - 3 PUFA and highlights distinctive effects between alpha-linolenic acid found in plant oils relative to marine derived eicosapentaenoic acid and docosahexaenoic acid. This review also highlights contrasting health effects between the n - 6 PUFA, linoleic and arachidonic acid.

Omega-3 polyunsaturated fatty acids and oxygenated metabolism in atherothrombosis

Numerous epidemiological studies and clinical trials have reported the health benefits of omega-3 polyunsaturated fatty acids (PUFA), including a lower risk of coronary heart diseases. This review mainly focuses on the effects of alpha-linolenic (ALA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on some risk factors associated with atherothrombosis, including platelet activation, plasma lipid concentrations and oxidative modification of low-density lipoproteins (LDL). Special focus is given to the effects of marine PUFA on the formation of eicosanoids and docosanoids, and to the bioactive properties of some oxygenated metabolites of omega-3 PUFA produced by cyclooxygenases and lipoxygenases. The antioxidant effects of marine omega-3 PUFA at low concentrations and the pro-oxidant effects of DHA at high concentrations on the redox status of platelets and LDL are highlighted. Non enzymatic peroxidation end-products deriving from omega-3 PUFA such as hydroxy-hexenals, neuroketals and EPA-derived isoprostanes are also considered in relation to atherosclerosis. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Benefits of foods supplemented with vegetable oils rich in α-linolenic, stearidonic or docosahexaenoic acid in hypertriglyceridemic subjects: a double-blind, randomized, controlled trail

PURPOSE

The aim of the study was to investigate the influence of foods enriched with vegetable oils varying in their n-3 polyunsaturated fatty acids profile on cardiovascular risk factors for hypertriglyceridemic subjects.

METHODS

Fifty-nine hypertriglyceridemic subjects (triglycerides ≥ 1.5 mmol/L) were included in the randomized, double-blind, placebo-controlled, crossover study. The placebo group received sunflower oil [linoleic acid (LA) group; 10 g LA/day]. The intervention groups received linseed oil [α-linolenic acid (ALA) group; 7 g ALA/day], echium oil [stearidonic acid (SDA) group; 2 g SDA/day] or microalgae oil [docosahexaenoic acid (DHA) group; 2 g DHA/day] over 10 weeks. Blood samples were collected at baseline and at the end of each period.

RESULTS

Total cholesterol (TC) and low-density-lipoprotein cholesterol decreased significantly in the LA and ALA groups (LA: P ≤ 0.01, ALA: P ≤ 0.05). No changes in blood lipids were observed in the SDA group. Significant increases in TC and high-density-lipoprotein cholesterol occurred in the DHA group (P ≤ 0.05). In the ALA and SDA groups, the content of eicosapentaenoic acid in erythrocyte lipids increased significantly (P ≤ 0.05) after 10 weeks (ALA group: 38 ± 37 %, SDA group: 73  ± 59 %).

CONCLUSION

Foods enriched with different vegetable oils rich in ALA or SDA are able to increase the n-3 long-chain polyunsaturated fatty acids content in erythrocyte lipids; echium oil is more potent in comparison with linseed oil. Blood lipids were beneficially modified through the consumption of food products enriched with sunflower, linseed and microalgae oils, whereas echium oil did not affect blood lipids. ClinicalTrials.gov: NCT01437930.

Effects of an energy-restricted diet rich in plant-derived α-linolenic acid on systemic inflammation and endothelial function in overweight-to-obese patients with metabolic syndrome traits

Plant-derived α-linolenic acid (ALA) may reduce the risk of CVD, possibly by decreasing systemic inflammation and improving endothelial function. In the present study, the effects of a hypoenergetic diet rich in ALA (3·4 g/d) on the biomarkers of systemic inflammation and vascular function were investigated in eighty-one overweight-to-obese patients with metabolic syndrome traits in comparison with a hypoenergetic diet low in ALA (0·9 g/d, control). After a 6-month dietary intervention, there were significant decreases in the serum concentrations of C-reactive protein (CRP), TNF-α, IL-6, soluble intercellular adhesion molecule-1 (sICAM-1), soluble endothelial selectin (sE-selectin) and asymmetric dimethylarginine in both dietary groups. However, no inter-group differences were observed for all these changes. The serum concentration of YKL-40 (human cartilage glycoprotein 39 or chitinase-3-like protein 1) decreased after the ALA diet when compared with the control diet (P< 0·05 for time × treatment interaction). Plasma concentrations of fibrinogen did not significantly change in the two dietary groups. The decreases in the serum concentrations of sICAM-1, sE-selectin, CRP and YKL-40 were significantly correlated with the decreases in body fat mass. In conclusion, the present study indicates that in overweight-to-obese patients with metabolic syndrome traits, both vascular function and inflammation are improved during body-weight loss. The high ALA intake led to a more pronounced reduction in the serum concentration of YKL-40 compared with the intake of the low-ALA control diet, indicating the existence of independent favourable physiological effects of ALA during weight loss.

Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review

The effects of both the amount and quality of dietary fat have been studied intensively during the past decades. Previously, low-fat diets were recommended without much attention to the quality of fat, whereas there is general emphasis on the quality of fat in current guidelines. The objective of this systematic review (SR) was to assess the evidence of an effect of the amount and type of dietary fat on body weight (BW), risk factors, and risk of non-communicable diseases, that is, type 2 diabetes (T2DM), cardiovascular diseases (CVD), and cancer in healthy subjects or subjects at risk for these diseases. This work was performed in the process of updating the fourth edition of the Nordic Nutrition Recommendations from 2004. The literature search was performed in October 2010 covering articles published since January 2000. A complementary search was done in February 2012 covering literature until December 2011. Two authors independently selected articles for inclusion from a total of about 16,000 abstracts according to predefined criteria. Randomized controlled trials (RCT) and prospective cohort studies (PCS) were included as well as nested case-control studies. A few retrospective case-control studies were also included when limited or no data were available from other study types. Altogether 607 articles were quality graded and the observed effects in these papers were summarized. Convincing evidence was found that partial replacement of saturated fat (SFA) with polyunsaturated fat (PUFA) or monounsaturated fat (MUFA) lowers fasting serum/plasma total and LDL cholesterol concentrations. The evidence was probable for a decreasing effect of fish oil on concentration of serum/plasma total triglycerides as compared with MUFA. Beneficial effect of MUFA both on insulin sensitivity and fasting plasma/serum insulin concentration was considered as probable in comparisons of MUFA and carbohydrates versus SFA, whereas no effect was found on fasting glucose concentration in these comparisons. There was probable evidence for a moderate direct association between total fat intake and BW. Furthermore, there was convincing evidence that partial replacement of SFA with PUFA decreases the risk of CVD, especially in men. This finding was supported by an association with biomarkers of PUFA intake; the evidence of a beneficial effect of dietary total PUFA, n-6 PUFA, and linoleic acid (LA) on CVD mortality was limited suggestive. Evidence for a direct association between total fat intake and risk of T2DM was inconclusive, whereas there was limited-suggestive evidence from biomarker studies that LA is inversely associated with the risk of T2DM. However, there was limited-suggestive evidence in biomarker studies that odd-chain SFA found in milk fat and fish may be inversely related to T2DM, but these associations have not been supported by controlled studies. The evidence for an association between dietary n-3 PUFA and T2DM was inconclusive. Evidence for effects of fat on major types of cancer was inconclusive regarding both the amount and quality of dietary fat, except for prostate cancer where there was limited-suggestive evidence for an inverse association with intake of ALA and for ovarian cancer for which there was limited-suggestive evidence for a positive association with intake of SFA. This SR reviewed a large number of studies focusing on several different health outcomes. The time period covered by the search may not have allowed obtaining the full picture of the evidence in all areas covered by this SR. However, several SRs and meta-analyses that covered studies published before year 2000 were evaluated, which adds confidence to the results. Many of the investigated questions remain unresolved, mainly because of few studies on certain outcomes, conflicting results from studies, and lack of high quality-controlled studies. There is thus an evident need of highly controlled RCT and PCS with sufficient number of subjects and long enough duration, specifically regarding the effects of the amount and quality of dietary fat on insulin sensitivity, T2DM, low-grade inflammation, and blood pressure. New metabolic and other potential risk markers and utilization of new methodology in the area of lipid metabolism may provide new insight.

α-Linolenic acid: nutraceutical, pharmacological and toxicological evaluation

α-Linolenic acid (ALA), a carboxylic acid with 18 carbons and three cis double bonds, is an essential fatty acid needed for human health and can be acquired via regular dietary intake of foods that contain ALA or dietary supplementation of foods high in ALA, for example flaxseed. ALA has been reported to have cardiovascular-protective, anti-cancer, neuro-protective, anti-osteoporotic, anti-inflammatory, and antioxidative effects. ALA is the precursor of longer chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but its beneficial effects on risk factors for cardiovascular diseases are still inconclusive. The recommended intake of ALA for cardiovascular health is reported to be 1.1-2.2g/day. Although there are limited toxicological data for ALA, no serious adverse effects have been reported. The evidence on an increased prostate cancer risk in association with dietary ALA is not conclusive. Based on the limited data currently available, it may be concluded that ALA may be beneficial as a nutraceutical/pharmaceutical candidate and is safe for use as a food ingredient.

Dietary modulators of statin efficacy in cardiovascular disease and cognition

Cardiovascular disease remains the leading cause of morbidity and mortality in the United States and other developed countries, and is fast growing in developing countries, particularly as life expectancy in all parts of the world increases. Current recommendations for the prevention of cardiovascular disease issued jointly from the American Academy of Cardiology and American Heart Association emphasize that lifestyle modification should be incorporated into any treatment plan, including those on statin drugs. However, there is a dearth of data on the interaction between diet and statins with respect to additive, complementary or antagonistic effects. This review collates the available data on the interaction of statins and dietary patterns, cognition, genetics and individual nutrients, including vitamin D, niacin, omega-3 fatty acids, fiber, phytochemicals (polyphenols and stanols) and alcohol. Of note, although the available data is summarized, the scope is limited, conflicting and disparate. In some cases it is likely there is unrecognized synergism. Virtually no data are available describing the interactions of statins with dietary components or dietary pattern in subgroups of the population, particularly those who may benefit most were positive effects identified. Hence, it is virtually impossible to draw any firm conclusions at this time. Nevertheless, this area is important because were the effects of statins and diet additive or synergistic harnessing the effect could potentially lead to the use of a lower intensity statin or dose.

Different dietary fatty acids are associated with blood lipids in healthy South African men and women: the PURE study

BACKGROUND

Preliminary data from the baseline Prospective Urban Rural Epidemiology (PURE) study in South Africa indicated a higher prevalence of dyslipidemia than previous South African studies. The intake of specific individual dietary fatty acids may affect blood lipids differently than sub-groups of fat (i.e. polyunsaturated fatty acids). We investigated the dietary intake of different individual fatty acids and their associations with blood lipids, in relation to urbanization and gender.

METHODS

Cross-sectional data analysis within the PURE baseline study of healthy subjects (n=1950, 35-70 years) from rural and urban areas. Dietary data were collected and blood lipid analysis performed.

RESULTS

Intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of n-3 PUFAs was below recommendations in all groups. Total cholesterol and LDL were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid (ALA) was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk for having elevated LDL also increased with increased intake of ALA (OR 1.49, 95% CI 1.04, 2.14) in males. In females, arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and arachidonic acid was also positively associated with LDL, whereas docosahexaenoic acid was negatively associated with total cholesterol and LDL.

CONCLUSIONS

These results suggest that specific individual dietary fatty acids may affect blood lipids in males differently than in females irrespective of rural or urban dwelling. The positive association between ALA and total cholesterol and triglycerides in males is a concern, because current advice aims to improve the dietary linoleic acid to ALA ratio by increasing ALA intake.

A randomized, double-blind placebo-controlled study on acceptability, safety and efficacy of oral administration of sacha inchi oil (Plukenetia volubilis L.) in adult human subjects

The study was designed to assess acceptability and side-effects of consumption of sacha inchi oil, rich in α-linolenic acid and sunflower oil, rich in linoleic acid, in adult human subjects. Thirty subjects received 10 or 15ml daily of sacha inchi or sunflower oil for 4months. Acceptability was assessed with daily self-report and with a Likert test at the end of the study. Safety was assessed with self- recording of side-effects and with hepatic and renal markers. Primary efficacy variables were the change in lipid profile. Subjects reported low acceptability of sacha inchi oil at week-1 (37.5%). However, since week-6, acceptability was significantly increased to 81.25-93.75%. No differences were observed in acceptability with respect to sex or oil volume (P>0.05). Most frequent adverse effects during first weeks of consuming sacha inchi oil or sunflower oil were nauseas. The side-effects were reduced with time. Biochemical markers of hepatic and kidney function were maintained unchanged. Serum total cholesterol and LDL cholesterol levels and arterial blood pressure were lowered with both oils (P<0.05). Higher HDL-cholesterol was observed with sacha inchi oil at month-4. In conclusion, sacha inchi oil consumed has good acceptability after week-1 of consumption and it is safety.

Exposure of fatty acids after a single oral administration of sacha inchi (Plukenetia volubilis L.) and sunflower oil in human adult subjects

CONTEXT

Sacha inchi (Plukenetia volubilis L.) is a potential oilseed crop because it is rich in α-linolenic acid (ALA) (omega-3 fatty acid).

OBJECTIVE

To evaluate the exposure of fatty acids after a single oral administration of sacha inchi or sunflower oil in healthy volunteers.

MATERIAL AND METHODS

Plasma fatty acids concentrations were assayed by Gas Chromatography with Flame Ionization Detector in 18 adult subjects. After fasting, blood samples were obtained at 0, 0.5, 1, 2, 4, 8 and 24 h after ingestion of 10 or 15 ml of sacha inchi oil or sunflower oil.

RESULTS

The proportion ALA/linoleic acid was 1.37 in sacha inchi oil and 0.01 in sunflower oil. ALA, lauric acid, palmitic acid, linolelaidic acid, cis-8,11,14-eicosatrienoic acid, cis-13,16-docosadienoic acid and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) levels changed over time after sacha inchi oil ingestion but not with sunflower oil. The time at maximal concentration (tmax) for ALA was 2 h after sacha inchi oil ingestion. No ALA in plasma was observed after sunflower oil consumption. The maximal concentration of ALA was 2.84 ± 0.36 mg/ml in women and 0.94 ± 0.57 mg/ml in men, p < 0.05, whereas maximal concentration of DHA was 2.60 ± 0.84 mg/ml in women and 1.00 ± 0.38 mg/ml in men (p > 0.05). There is a trend for higher plasma ALA levels with 15 ml sacha inchi oil. After 2 h of consumption, plasma delta triacylglycerol were reduced with sunflower oil but slightly increased with sacha inchi oil. A reduction in plasma delta triacylglycerol-rich lipoprotein cholesterol was observed with both oils.

CONCLUSION

Consumption of sacha inchi oil increased ALA and DHA in plasma.

Icosapent ethyl, a pure EPA omega-3 fatty acid: effects on plasma and red blood cell fatty acids in patients with very high triglyceride levels (results from the MARINE study)

INTRODUCTION

Icosapent ethyl (IPE) is a high-purity prescription form of eicosapentaenoic acid (EPA) ethyl ester. We evaluated IPE's effects on plasma and red blood cell (RBC) fatty acids (FA) and the relationship to triglyceride (TG) lowering.

MATERIALS AND METHODS

This was a predefined, exploratory analysis (N=229) of FA plasma concentration and RBC membrane content from the double-blind, placebo-controlled MARINE study.

RESULTS

Mean placebo-adjusted plasma EPA levels increased from baseline by 792% and 402% and the arachidonic acid/EPA plasma ratio decreased from baseline by 99% and 88% with IPE 4 g/day and 2 g/day, respectively (all P<.0001). Overall, the fractional pool of omega-3 FAs increased; there was a decrease or no change for omega-6 FAs. The increase in EPA levels with increased IPE dose corresponded with the TG-lowering effect. Similar FA shifts were observed in RBCs.

CONCLUSIONS

IPE significantly increased plasma and RBC FAs, which correlated to TG lowering.

Atherosclerosis, dyslipidemia, and inflammation: the significant role of polyunsaturated Fatty acids

Phospholipids play an essential role in cell membrane structure and function. The length and number of double bonds of fatty acids in membrane phospholipids are main determinants of fluidity, transport systems, activity of membrane-bound enzymes, and susceptibility to lipid peroxidation. The fatty acid profile of serum lipids, especially the phospholipids, reflects the fatty acid composition of cell membranes. Moreover, long-chain n-3 polyunsatured fatty acids decrease very-low-density lipoprotein assembly and secretion reducing triacylglycerol production. N-6 and n-3 polyunsatured fatty acids are the precursors of signalling molecules, termed "eicosanoids," which play an important role in the regulation of inflammation. Eicosanoids derived from n-6 polyunsatured fatty acids have proinflammatory actions, while eicosanoids derived from n-3 polyunsatured fatty acids have anti-inflammatory ones. Previous studies showed that inflammation contributes to both the onset and progression of atherosclerosis: actually, atherosclerosis is predominantly a chronic low-grade inflammatory disease of the vessel wall. Several studies suggested the relationship between long-chain n-3 polyunsaturated fatty acids and inflammation, showing that fatty acids may decrease endothelial activation and affect eicosanoid metabolism.

Epanova® and hypertriglyceridemia: pharmacological mechanisms and clinical efficacy

While LDL-cholesterol lowering has become the cornerstone of cardiovascular risk reduction strategies, considerable interest in additional targeting of hypertriglyceridemia continues. While ω-3 fatty acids are commonly used in clinical practice for triglyceride lowering, no large-scale clinical trial evaluating their impact on clinical events has been performed. As a result, there remains a lack of consensus with regards to their optimal clinical use. Epanova® (Omthera Pharmaceuticals Inc., NJ, USA) is a novel ω-3 free fatty acid formulation, developed to maximize eicosapentenoic acid and docosahexenoic acid bioavailability with low-fat diets, suggesting a potential therapeutic advantage compared with ω-3-acid ethyl esters in the treatment of patients with hypertriglyceridemia. Additional human studies are needed to define more clearly the cellular and molecular basis for the triglyceride-lowering effects of Epanova and this drug’s favorable cardiovascular effects, particularly in patients with hypertriglyceridemia.

The role of marine n-3 fatty acids in improving cardiovascular health: a review

Omega 3 polyunsaturated fatty acids (n-3 PUFA) have long been studied for their health benefits. In particular, marine n-3 PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to possess cardiovascular protective qualities. However, there is conflicting evidence as to the mechanisms, effectiveness and doses required to observe these benefits. The objective of this review is to provide existing evidence as to the role of marine n-3 PUFA on cardiovascular health, as well as provide novel aspects to the current literature as of September 2012. Three large randomized clinical studies were reviewed to determine if there was an inverse association between n-3 fatty acid intake and CVD. There is strong evidence that the pharmaceutical grade n-3 fatty acid drug Lovaza, (previously Omacor) is effective in reducing triglyceride levels in humans. However, there are possible adverse reactions that need to be taken into account and caution should be used in treating certain populations. The Omega-3 Index is a promising novel biomarker for assessing long term EPA + DHA status in humans. Due to the originality of the Index, additional evidence is required to assess this as a tool for predicting CVD. Future research is needed to determine the individual effects of EPA and DHA for cardio-protection.

Distinguishing health benefits of eicosapentaenoic and docosahexaenoic acids

Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) are recommended for management of patients with wide-ranging chronic diseases, including coronary heart disease, rheumatoid arthritis, dementia, and depression. Increased consumption of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is recommended by many health authorities to prevent (up to 0.5 g/day) or treat chronic disease (1.0 g/day for coronary heart disease; 1.2–4 g/day for elevated triglyceride levels). Recommendations for dietary intake of LC n-3 PUFAs are often provided for α-linolenic acid, and for the combination of EPA and DHA. However, many studies have also reported differential effects of EPA, DHA and their metabolites in the clinic and at the laboratory bench. The aim of this article is to review studies that have identified divergent responses to EPA and DHA, and to explore reasons for these differences. In particular, we review potential contributing factors such as differential membrane incorporation, modulation of gene expression, activation of signaling pathways and metabolite formation. We suggest that there may be future opportunity to refine recommendations for intake of individual LC n-3 PUFAs.

Margarines fortified with α-linolenic acid, eicosapentaenoic acid, or docosahexaenoic acid alter the fatty acid composition of erythrocytes but do not affect the antioxidant status of healthy adults

We aimed to investigate the effects of increased intake of α-linolenic acid (ALA), EPA, or DHA incorporated into a food matrix on the fatty acid composition of erythrocytes and on biomarkers of oxidant/antioxidant status. To this end, a controlled dietary study was conducted in 74 healthy men and women. The participants were randomly assigned to 1 of 3 interventions in which margarines fortified with either 10 weight percent ALA, EPA, or DHA ethyl esters replaced their normal spread for 6 wk. The total intakes of ALA, EPA, and DHA were 4.4, 2.2, and 2.3 g/d, respectively. Consuming EPA increased the erythrocyte proportion of EPA (394%) and the omega-3 index (sum of EPA and DHA, 38%). Consumption of DHA increased erythrocyte DHA (91%), the omega-3 index (98%), and EPA (137%). The omega-3 index increased to a significantly greater extent in the DHA group than in the EPA group. ALA did not increase erythrocyte EPA or the omega-3 index. We found no change in plasma uric acid or antioxidant capacity in any of the groups. Plasma malondialdehyde (MDA) increased with the EPA and DHA interventions. All 3 interventions decreased erythrocyte linoleic acid hydroperoxides but did not affect their MDA concentrations. In conclusion, the intake of both isolated EPA and DHA incorporated into margarine resulted in an enhanced incorporation of EPA and DHA into erythrocytes. Our findings indicate that DHA is quantitatively superior to EPA in view of the EPA+DHA tissue incorporation and also that 4 g/d ALA is not sufficient to increase the omega-3 index over a 6-wk period.

Effects of a rapeseed oil-enriched hypoenergetic diet with a high content of α-linolenic acid on body weight and cardiovascular risk profile in patients with the metabolic syndrome

In therapy of the metabolic syndrome, the optimal dietary approach with regard to its macronutrient composition and metabolically favourable food components, such as the plant-derived n-3 fatty acid α-linolenic acid (ALA), is still a matter of debate. We investigated the effects of a hypoenergetic diet with low energy density (ED) enriched in rapeseed oil, resulting in high MUFA content and an ALA intake of 3·5 g/d on body weight and cardiovascular risk profile in eighty-one patients with the metabolic syndrome in comparison with an olive oil diet rich in MUFA, but with a low ALA content. After a 6-month dietary intervention, body weight was significantly reduced in the rapeseed oil and olive oil groups ( − 7·8 v. − 6·0 kg; P < 0·05). There were significant decreases in systolic blood pressure, total cholesterol and LDL-cholesterol, and insulin levels in both groups (P < 0·05). For all of these changes, no inter-group differences were observed. After the rapeseed oil diet, diastolic blood pressure declined more than after the olive oil diet (P < 0·05 for time × group interaction). Furthermore, concentrations of serum TAG were significantly reduced after the high ALA intake, but not in the low ALA group (P < 0·05 for time × group interaction). In conclusion, our dietary food pattern with a low ED and high intakes of MUFA and ALA may be a practical approach for long-term dietary treatment in patients with the metabolic syndrome, leading to weight reduction and an improvement in the overall cardiovascular risk profile.

Circulating and dietary α-linolenic acid and incidence of congestive heart failure in older adults: the Cardiovascular Health Study

BACKGROUND

Few studies have evaluated the association between the n-3 fatty acid α-linolenic acid (ALA) and the incidence of congestive heart failure (CHF).

OBJECTIVE

We investigated whether plasma phospholipid concentrations and estimated dietary consumption of ALA are associated with incident CHF.

DESIGN

We used data from the Cardiovascular Health Study, a prospective cohort study of cardiovascular diseases among adults aged ≥65 y, from 4 US communities. A total of 2957 participants free of prevalent heart disease and with available fatty acid measurements were included in biomarker analyses (30,722 person-years and 686 incident CHF events). A total of 4432 participants free of prevalent heart disease were included in dietary analyses (52,609 person-years and 1072 events). We investigated the association of ALA with incident CHF by using Cox regression.

RESULTS

After adjustment for age, sex, race, education, smoking status, BMI, waist circumference, and alcohol consumption, plasma phospholipid ALA was not associated with incident CHF (HR for the highest compared with the lowest quartile: 0.97; 95% CI: 0.79, 1.21; P-trend = 0.85). Likewise, dietary ALA was not associated with incident CHF (adjusted HR for the highest compared with the lowest quartile: 0.96; 95% CI: 0.82, 1.20; P-trend = 0.97). We observed no association of biomarker or dietary ALA with nonvalvular CHF subtype. We also found little evidence of an association between ALA and CHF in subgroups based on age, sex, diabetes, fish consumption, BMI, or FADS2 genotype (rs1535).

CONCLUSION

ALA intake is not associated with incident CHF in older adults. This trial was registered at clinicaltrials.gov as NCT00005133.

Arachidonate 5-lipoxygenase gene variants affect response to fish oil supplementation by healthy African Americans

Arachidonate 5-lipoxygenase (ALOX5) gene variants that are common in people of African ancestry are associated with a differential cardiovascular disease (CVD) risk that may be ameliorated by intake of (n-3) PUFA, such as EPA or DHA. We conducted a double-masked, placebo (PL)-controlled trial of fish oil (FO) supplements to determine if changes in erythrocyte (n-3) PUFA composition, heart rate, blood pressure, and plasma lipid and lipoprotein concentrations are modified by genotype. Participants received 5 g/d FO (2 g EPA, 1 g DHA) or 5 g/d corn/soy oil (PL). A total of 116 healthy adults of African ancestry with selected genotypes (genotypes = "dd," "d5," and "55" with "d" representing the deletion of 1 or 2 Sp1 binding sites in the ALOX5 promoter and "5" indicating the common allele with 5 sites) were enrolled and 98 completed the study. FO caused significant increases (relative to PL) in erythrocyte EPA, DHA, and total (n-3) PUFA and a decrease in the (n-6) PUFA:(n-3) PUFA ratio in the low-CVD risk "d5" and "55" genotypes but not in the high-risk "dd" genotype. Similarly, HDL particle concentration decreased with FO relative to PL in the "d5" and "55" but not "dd" genotypes. The plasma TG concentration decreased significantly with FO relative to PL in the "d5" but not "dd" and "55" genotypes. No changes were seen in LDL particle or cholesterol concentrations, heart rate, or blood pressure. These findings indicate that the efficacy of FO supplements vary by ALOX5 genotype.

The change in low-density lipoprotein cholesterol concentration is positively related to plasma docosahexaenoic acid but not eicosapentaenoic acid

AIM

The Japan EPA Lipid Intervention Study (JELIS) reported a 19% reduction of the risk for coronary artery disease after long-term use of pure eicosapentaenoic acid (EPA) in Japanese patients with hypercholesterolemia. The variation in plasma fatty acid composition influenced the risk of coronary events. The aim of this study was to examine in JELIS participants the possible correlation of changes in plasma fatty acids with those of serum lipids.

METHODS

The coefficient for the correlation between the absolute change in plasma fatty acid concentrations and the changes in serum lipids was calculated in 13,901 JELIS participants.

RESULTS

Low-density lipoprotein (LDL) cholesterol exhibited a positive correlation with docosahexaenoic acid (DHA; r=0.117 in control group, r=0.155 in EPA group) and linoleic acid (r=0.139 in control group, r=0.177 in EPA group), but the correlation coefficients with EPA (r=0.097 in control group, r=-0.032 in EPA group) were less than 0.1. We distributed the patients into 9 groups according to tertiles of the change in EPA and DHA. The average absolute decrease of LDL cholesterol and L/H ratio in each group was significantly smaller (p<0.001) in the DHA-high tertile, but not in any EPA tertile.

CONCLUSION

The changes in DHA, but not in EPA, showed a positive correlation with the changes in LDL-cholesterol.

Dietary sources of omega 3 fatty acids: public health risks and benefits

Omega 3 fatty acids can be obtained from several sources, and should be added to the daily diet to enjoy a good health and to prevent many diseases. Worldwide, general population use omega-3 fatty acid supplements and enriched foods to get and maintain adequate amounts of these fatty acids. The aim of this paper was to review main scientific evidence regarding the public health risks and benefits of the dietary sources of omega-3 fatty acids. A systematic literature search was performed, and one hundred and forty-five articles were included in the results for their methodological quality. The literature described benefits and risks of algal, fish oil, plant, enriched dairy products, animal-derived food, krill oil, and seal oil omega-3 fatty acids.

Stearidonic acid-enhanced soybean oil: a plant-based source of (n-3) fatty acids for foods

Omega-3 (n-3) fatty acids have been reported to have a variety of cardiovascular and neuropsychiatric benefits. Although obtaining the preformed fatty acids EPA and DHA from their traditional source (fish) is optimal, such an approach may not be realistic for meeting the world's growing demand for (n-3) fatty acids; therefore, a more sustainable and dependable source is needed. Stearidonic acid (SDA) is a metabolic precursor of EPA that can be provided by SDA-enhanced soybean oil. Such a product can provide a sustainable source of (n-3) fatty acids that does not endanger fish stocks. Two clinical trials have demonstrated that SDA-enhanced soybean oil can significantly improve an emerging marker of cardiovascular health, the omega-3 index (RBC EPA+DHA). The increase in the Index seen in these trials was used to estimate the potential clinical benefit of SDA consumption based on prior prospective cohort studies. In this analysis, risk for sudden cardiac death and the rate of cellular aging would both theoretically be reduced. The lower risk for major cardiac events seen in the Japan EPA Lipid Intervention Study (which used EPA supplementation) suggests that raising EPA tissue levels, independent of changes in DHA, can have clinical benefit. Thus, the consumption of foods containing SDA-enhanced soybean oil may be both a practical and sustainable approach to enriching tissues with beneficial (n-3) fatty acids.

(n-3) fatty acids and cardiovascular health: are effects of EPA and DHA shared or complementary?

Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil. Whether individual long-chain (n-3) PUFA have shared or complementary effects is not well established. We reviewed evidence for dietary and endogenous sources and cardiovascular effects on biologic pathways, physiologic risk factors, and clinical endpoints of EPA [20:5(n-3)], docosapentaenoic acid [DPA, 22:5(n-3)], and DHA [22:6(n-3)]. DHA requires direct dietary consumption, with little synthesis from or retroconversion to DPA or EPA. Whereas EPA is also largely derived from direct consumption, EPA can also be synthesized in small amounts from plant (n-3) precursors, especially stearidonic acid. In contrast, DPA appears principally derived from endogenous elongation from EPA, and DPA can also undergo retroconversion back to EPA. In experimental and animal models, both EPA and DHA modulate several relevant biologic pathways, with evidence for some differential benefits. In humans, both fatty acids lower TG levels and, based on more limited studies, favorably affect cardiac diastolic filling, arterial compliance, and some metrics of inflammation and oxidative stress. All three (n-3) PUFA reduce ex vivo platelet aggregation and DHA also modestly increases LDL and HDL particle size; the clinical relevance of such findings is uncertain. Combined EPA+DHA or DPA+DHA levels are associated with lower risk of fatal cardiac events and DHA with lower risk of atrial fibrillation, suggesting direct or indirect benefits of DHA for cardiac arrhythmias (although not excluding similar benefits of EPA or DPA). Conversely, EPA and DPA, but not DHA, are associated with lower risk of nonfatal cardiovascular endpoints in some studies, and purified EPA reduced risk of nonfatal coronary syndromes in one large clinical trial. Overall, for many cardiovascular pathways and outcomes, identified studies of individual (n-3) PUFA were relatively limited, especially for DPA. Nonetheless, the present evidence suggests that EPA and DHA have both shared and complementary benefits. Based on current evidence, increasing consumption of either would be advantageous compared to little or no consumption. Focusing on their combined consumption remains most prudent given the potential for complementary effects and the existing more robust literature on cardiovascular benefits of their combined consumption as fish or fish oil for cardiovascular benefits.

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.

Effects of eicosapentaenoic acid versus docosahexaenoic acid on serum lipids: a systematic review and meta-analysis

Omega-3 fatty acid supplements containing both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to reduce triglycerides but also increase low-density lipoprotein (LDL). Whether EPA or DHA given as monotherapy has differential effects on serum lipoproteins has not been systematically evaluated. We performed a meta-analysis of randomized placebo-controlled trials of monotherapy with EPA (n=10), DHA (n=17), or EPA versus DHA (n=6). Compared with placebo, DHA raised LDL 7.23 mg/dL (95% CI, 3.98–10.5) whereas EPA non-significantly reduced LDL. In direct comparison studies, DHA raised LDL 4.63 mg/dL (95% CI, 2.15–7.10) more than EPA. Both EPA and DHA reduced triglycerides, with a greater reduction by DHA in direct comparison studies. DHA also raised high-density lipoprotein (4.49 mg/dL; 95% CI, 3.50–5.48) compared with placebo, whereas EPA did not. Although EPA and DHA both reduce triglycerides, they have divergent effects on LDL and high-density lipoprotein. Further research is needed to elucidate the mechanisms and significance of these differences.

Novel developments in omega-3 fatty acid-based strategies

PURPOSE OF REVIEW

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been attributed with several health benefits, including triglyceride lowering and cardiovascular disease risk reduction. This review focuses on new prescription omega-3 fatty acid products in development and recently published data regarding omega-3 fatty acid effects on arrhythmias, heart failure, and platelet inactivation.

RECENT FINDINGS

A free fatty acid form of n-3 PUFA was found to produce a four-fold higher area under the plasma n-3 PUFA curve than prescription omega-3-acid ethyl esters in patients on a low-fat diet. Eicosapentaenoic acid ethyl esters reduced triglyceride without significantly elevating LDL cholesterol in patients with severe hypertriglyceridemia and in those with mixed dyslipidemia. Recent investigations of n-3 PUFA effects on ventricular and atrial arrhythmias, including studies in patients with implanted defibrillators, failed to demonstrate a significant benefit. However, increased fatty fish or n-3 PUFA consumption was associated with a lower rate of hospitalization in heart failure patients. A further important finding was potentiation of the antiplatelet response when n-3 PUFAs were added to aspirin + clopidogrel.

SUMMARY

Although n-3 PUFA therapy continues to show promise in the prevention and management of cardiovascular diseases, further research is necessary to more fully elucidate its role in specific disorders.

Effects of eicosapentaenoic acid and docosahexaenoic acid on low-density lipoprotein cholesterol and other lipids: a review

In this exploratory, hypothesis-generating literature review, we evaluated potentially differential effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and non-HDL-C in published studies of ω-3 fatty acid supplementation or prescription ω-3 fatty acid ethyl esters. Placebo-adjusted changes in mean lipid parameters were compared in randomized, controlled trials in subjects treated for ≥ 4 weeks with DHA or EPA. Of 22 studies identified, 6 compared DHA with EPA directly, 12 studied DHA alone (including 14 DHA-treated groups), and 4 examined EPA alone. In studies directly comparing EPA with DHA, a net increase in LDL-C of 3.3% was observed with DHA (DHA: +2.6%; EPA: -0.7%). In such head-to-head comparative studies, DHA treatment was associated with a net decrease in TG by 6.8% (DHA: -22.4%; EPA: -15.6%); a net increase in non-HDL-C by 1.7% (DHA: -1.2%; EPA -2.9%); and a net increase in HDL-C by 5.9% (DHA: +7.3%; EPA: +1.4%). Increases in LDL-C were also observed in 71% of DHA-alone groups [with demonstrated statistical significance (P < .05) in 67% (8 of 12) DHA-alone studies] but not in any EPA-alone studies. Changes in LDL-C significantly correlated with baseline TG for DHA-treated groups. The range of HDL-C increases documented in DHA-alone vs EPA-alone studies further supports the fact that HDL-C is increased more substantially by DHA than EPA. In total, these findings suggest that DHA-containing supplements or therapies were associated with more significant increases in LDL-C and HDL-C than were EPA-containing supplements or therapies. Future prospective, randomized trials are warranted to confirm these preliminary findings, determine the potential effects of these fatty acids on other clinical outcomes, and evaluate the generalizability of the data to larger and more heterogeneous patient populations.