Habitual dietary intake of n-3 and n-6 fatty acids in relation to inflammatory markers among US men and women

N-3 fatty acid supplementation to routine statin treatment inhibits platelet function, decreases patients' daytime blood pressure, and improves inflammatory status

OBJECTIVES

N-3 fatty acids reduce the risks of cardiovascular morbidity and mortality. Administration of N-3 fatty acids to patients treated with statins may potentiate the treatment effects. We examined the operating mechanisms underlying such a combination.

METHODS

Thirty-two hypercholesterolemic patients aged 30-70 years with hypercholesterolemia controlled by statins, received sequential treatments with placebo followed by 1.9 g/day of N-3 fatty acids for 23 weeks. Scheduled clinical visits included physical examination, 24-h blood pressure measurement, endothelial function evaluated by pulse wave analysis, analyses for platelet function, inflammation markers [interleukin (IL)-6, plasminogen activator inhibitor-1 (PAI-1)] and oxidative stress parameters (STAT-8-Isoprostane) were undertaken at baseline, after placebo treatment, and after 6 and 20 weeks of N-3 fatty acid intake.

RESULTS

Platelets functions were significantly inhibited, whereas endothelial function parameters were unaltered. IL-6 significantly decreased whereas PAI-1and STAT-8-Isoprostane levels remained unaffected. Daytime blood pressure significantly decreased; however, nighttime pressure and heart rate remained unchanged. No evidence of lipid-profile improvement was observed following combined treatment with statins and N-3 fatty acids.

CONCLUSIONS

In hypercholesterolemic patients, combination of statins and N-3 fatty acid inhibits platelet aggregation, alters inflammatory status, and positively affects daytime blood pressure. Close long-term follow-up might reveal additional beneficial effects of N-3 fatty acids in this patient population.

Ethnicity, plasma phospholipid fatty acid composition and inflammatory/endothelial activation biomarkers in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND/OBJECTIVES

It has been recognized that certain long-chain polyunsaturated fatty acids (LC-PUFAs) are involved in inflammation and its resolution. It has also been shown that ethnicity may be a factor in affecting systemic inflammation, and limited evidence suggests it may influence plasma LC-PUFA composition. Given the links among these three factors, we aim to determine ethnicity-based differences in plasma LC-PUFA composition among White, Black, Hispanic and Chinese participants, and whether such differences contribute to variations in markers of inflammation and endothelial activation in a sub-cohort of the Multi-Ethnic Study of Atherosclerosis (MESA).

SUBJECTS/METHODS

Plasma phospholipid LC-PUFAs levels (%) were determined in 2848 MESA participants using gas chromatography-flame ionization detection. Enzyme immunoassays determined inflammatory markers levels for high-sensitivity C-reactive protein (n=2848), interleukin-6 (n=2796), soluble tumor necrosis factor-α receptor type 1 (n=998), and endothelial activation markers soluble intercellular adhesion molecule-1 (n=1192) and soluble E-selectin (n=998). The modifying influence of ethnicity was tested by linear regression analysis.

RESULTS

Chinese adults were found to have the highest mean levels of plasma eicosapentaenoic acid (EPA, 1.24%) and docosahexaenoic acid (DHA, 4.95%), and the lowest mean levels of γ-linolenic (0.10%), dihomo-γ-linolenic (DGLA, 2.96%) and arachidonic (10.72%) acids compared with the other ethnicities (all P ≤ 0.01). In contrast, Hispanics had the lowest mean levels of plasma EPA (0.70%) and DHA (3.49%), and the highest levels of DGLA (3.59%; all P ≤ 0.01). Significant differences in EPA and DHA among ethnicities were attenuated following adjustment for dietary non-fried fish and fish oil supplementation. Ethnicity did not modify the associations of LC-PUFAs with markers of inflammation or endothelial activation (all P (interaction)>0.05).

CONCLUSIONS

The absence of a modifying effect of ethnicity indicates that the putative benefits of LC-PUFAs with respect to inflammation are pan-ethnic. Future longitudinal studies may elucidate the origin(s) of ethnicity-based differences in LC-PUFA composition and whether certain patterns, that is, high plasma levels of DGLA and low levels of EPA/DHA, contribute to inflammation-associated health outcomes.

The role of psychoneuroimmunology in personalized and systems medicine

Psychoneuroimmunology (PNI) may provide the scientific basis for personalized and systems medicine. The exploration of the extensive interactions among psychological and behavioral factors, the nervous system, the immune system, and the endocrine system may help understand the mechanisms underlying health, wellness, and diseases. PNI theories based on systems biology methodologies may contribute to the identification of patient patterns for establishing psychological and physiological profiles for personalized medicine. A biopsychosocial model will help elucidate the systemic interrelationships between psychosocial and bio-physiological factors for the development of systems medicine. Many evidences have supported the close relationships between stress, depression, inflammation, and disorders including obesity, cardiovascular disease, diabetes, arthritis, skin diseases, infectious diseases, and sleep disorders. As inflammation is a critical connection among different diseases, the elucidation of the associations may contribute to the findings of systemic therapeutic targets. With the understanding of the translational implications of PNI, integrative interventions in multiple dimensions can be applied to modulate stress responses and promote healthier behaviors. These interventions include combination drug therapies, diets, nutritional supplements, meditation, and other behavioral and mind-body strategies.

Therapeutic drugs: healing power of marine fish

Marine fish is a major source of high-quality protein, lipids, and a wide variety of vitamins and minerals. These macromolecules and their derivatives show different pharmacological activities, which make the fish as a therapeutic diet. Modern technology has made it easy to explore the therapeutic importance of fish-based diet on cardiovascular diseases, neurodegenerative diseases, radicals-mediated diseases, and cancer. In this review, we focus on exploration of proteins, lipids, carbohydrates, minerals, and their derivatives from marine fish as a major source for bioactive compounds and their medicinal importance.

Metabolic and endocrine effects of long-chain versus essential omega-3 polyunsaturated fatty acids in polycystic ovary syndrome

The objective of the study was to compare the effects of essential vs long-chain omega (n)-3 polyunsaturated fatty acids (PUFAs) in polycystic ovary syndrome. In this 6-week, prospective, double-blinded, placebo (soybean oil)-controlled study, 51 completers received 3.5 g n-3 PUFA per day (essential PUFA from flaxseed oil or long-chain PUFA from fish oil). Anthropometric variables, cardiovascular risk factors, and androgens were measured; oral glucose tolerance test (OGTT) and frequently sampled intravenous GTT (IVGTT) were conducted at baseline and 6 weeks. Between-group comparisons showed significant differences in serum triglyceride response (P = .0368), whereas the changes in disposition index also tended to differ (P = .0621). When within-group changes (after vs before intervention) were considered, fish oil and flaxseed oil lowered serum triglyceride (P = .0154 and P = .0176, respectively). Fish oil increased glucose at 120 minutes of OGTT (P = .0355), decreased the Matsuda index (P = .0378), and tended to decrease acute insulin response during IVGTT (P = .0871). Soybean oil increased glucose at 30 (P = .0030) and 60 minutes (P = .0121) and AUC for glucose (P = .0122) during OGTT, tended to decrease acute insulin response during IVGTT (P = .0848), reduced testosterone (P = .0216), and tended to reduce sex hormone-binding globulin (P = .0858). Fasting glucose, insulin, adiponectin, leptin, or high-sensitivity C-reactive protein did not change with any intervention. Long-chain vs essential n-3 PUFA-rich oils have distinct metabolic and endocrine effects in polycystic ovary syndrome; and therefore, they should not be used interchangeably.

Association of serum n-3 polyunsaturated fatty acids with C-reactive protein in men

BACKGROUND/OBJECTIVES

N-3 polyunsaturated fatty acids (PUFAs) have been associated with reduced inflammation. We tested the hypothesis that high serum concentrations of the n-3 PUFAs are associated with lower serum C-reactive protein (CRP) concentrations in healthy middle-aged Finnish men. We also examined whether exposure to mercury, an environmental contaminant in fish, which is also a major source of long-chain n-3 PUFA, was associated with CRP.

SUBJECTS/METHODS

Data from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study were analyzed cross-sectionally to determine the associations between serum n-3 PUFAs, hair mercury and serum CRP in 1395 healthy men, aged 42-60 years. Linear regression analyses were performed to analyze the associations.

RESULTS

In the multivariate models, the mean serum CRP in quartiles of serum total n-3 PUFA concentration was 1.23, 1.27, 1.18 and 1.08 mg/l, P for trend = 0.01. Statistically significant inverse associations were also observed with the total serum long-chain n-3 PUFA concentration and with the individual long-chain n-3 PUFAs docosapentaenoic acid and docosahexaenoic acid, but not with eicosapentaenoic acid or with the intermediate-chain n-3 PUFA alpha-linolenic acid. Hair methylmercury content was not associated with serum CRP levels and it did not modify the associations between serum n-3 PUFAs and CRP either.

CONCLUSIONS

Serum n-3 PUFAs and especially the long-chain n-3 PUFA concentration, a marker of fish or fish oil consumption, were inversely associated with serum CRP in men. Exposure to mercury was not associated with serum CRP.

Coordinated defects in hepatic long chain fatty acid metabolism and triglyceride accumulation contribute to insulin resistance in non-human primates

Non-Alcoholic fatty liver disease (NAFLD) is characterized by accumulation of triglycerides (TG) in hepatocytes, which may also trigger cirrhosis. The mechanisms of NAFLD are not fully understood, but insulin resistance has been proposed as a key determinant.

Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial

Observational studies have linked lower omega-3 (n-3) polyunsaturated fatty acids (PUFAs) and higher omega-6 (n-6) PUFAs with inflammation and depression, but randomized controlled trial (RCT) data have been mixed. To determine whether n-3 decreases proinflammatory cytokine production and depressive and anxiety symptoms in healthy young adults, this parallel group, placebo-controlled, double-blind 12-week RCT compared n-3 supplementation with placebo. The participants, 68 medical students, provided serial blood samples during lower-stress periods as well as on days before an exam. The students received either n-3 (2.5 g/d, 2085 mg eicosapentaenoic acid and 348 mg docosahexanoic acid) or placebo capsules that mirrored the proportions of fatty acids in the typical American diet. Compared to controls, those students who received n-3 showed a 14% decrease in lipopolysaccharide (LPS) stimulated interleukin 6 (IL-6) production and a 20% reduction in anxiety symptoms, without significant change in depressive symptoms. Individuals differ in absorption and metabolism of n-3 PUFA supplements, as well as in adherence; accordingly, planned secondary analyses that used the plasma n-6:n-3 ratio in place of treatment group showed that decreasing n-6:n-3 ratios led to lower anxiety and reductions in stimulated IL-6 and tumor necrosis factor alpha (TNF-α) production, as well as marginal differences in serum TNF-α. These data suggest that n-3 supplementation can reduce inflammation and anxiety even among healthy young adults. The reduction in anxiety symptoms associated with n-3 supplementation provides the first evidence that n-3 may have potential anxiolytic benefits for individuals without an anxiety disorder diagnosis. ClinicalTrials.gov identifier: NCT00519779.

Fibroblast growth factor 23, cardiovascular disease risk factors, and phosphorus intake in the health professionals follow-up study

BACKGROUND AND OBJECTIVES

Fibroblast growth factor 23 (FGF23) regulates phosphorus and vitamin D metabolism. Elevated FGF23 concentrations are associated with cardiovascular disease events and mortality across a broad range of kidney function, but the predictors of FGF23 concentrations in the general population are unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined cross-sectional associations of dietary and nondietary parameters with plasma FGF23 in 1261 participants of the Health Professionals Follow-up Study (mean age 64 ± 9, mean creatinine 0.9 ± 0.2 mg/dl, mean FGF23 64 ± 28 RU/ml).

RESULTS

In multivariable-adjusted analyses, each 5-year increase in age was associated with 2.1 RU/ml higher FGF23, each 500-mg increase in phosphorus intake was associated with 3.4 RU/ml higher FGF23, and each 0.1-mg/dl increase in creatinine was associated with 3.4 RU/ml higher FGF23. Participants in the highest category of body mass index had 9.5 RU/ml higher FGF23 than those in the lowest, smokers had 17.1 RU/ml higher FGF23 than nonsmokers, and participants with hypertension had 6.0 RU/ml higher FGF23 than those without hypertension. With respect to biochemical parameters, higher parathyroid hormone, phosphate, uric acid, and triglyceride levels all were associated independently with higher FGF23 in models adjusted for age, creatinine, and other factors. In a subset of 748 participants with available data, some inflammatory biomarkers were associated independently with higher FGF23.

CONCLUSIONS

In community-dwelling adults with largely preserved kidney function, established cardiovascular risk factors and higher phosphorus intake were associated with higher FGF23. These results might explain the link between FGF23 and cardiovascular disease.

Dietary α-linolenic acid, linoleic acid, and n-3 long-chain PUFA and risk of ischemic heart disease

BACKGROUND

n-3 (omega-3) PUFA has been proposed as having health-promoting effects, primarily in relation to ischemic heart disease (IHD). Whether these benefits can be achieved by both α-linolenic acid (ALA, 18:3n-3) and n-3 long-chain PUFA (LC-PUFA) is debatable.

OBJECTIVE

The objective was to examine the association between ALA intake and risk of IHD in healthy subjects and to see if this was modified by intake of n-3 LC-PUFA or linoleic acid (LA, 18:2 n-6).

DESIGN

This was a prospective cohort study of 3277 healthy Danish women and men free of known IHD.

RESULTS

Four hundred seventy-one cases of IHD were observed during a median follow-up period of 23.3 y. Higher intake of ALA was not significantly associated with decreased risk of IHD among women or men. Although the HR of IHD was stepwise decreased with increasing ALA intake in men [0.84 (95% CI: 0.62, 1.14) in the medium compared with the lowest tertile (reference) and 0.83 (95% CI: 0.56, 1.24) in the highest compared with the lowest tertile], this change was far from significant (P-trend: 0.39). No evidence of effect modification by n-3 LC-PUFA or LA was observed. High n-3 LC-PUFA intake, in comparison with low intake, was inversely associated with risk of IHD; this trend was significant in women (P = 0.04; HR: 0.62; 95% CI: 0.40, 0.97) but not in men (P = 0.15; HR: 0.74; 95% CI: 0.51, 1.06). No associations were observed between intake of LA and risk of IHD.

CONCLUSION

This study suggests that there is no association between ALA intake and risk of IHD, but a high intake of n-3 LC-PUFA had a significant cardioprotective effect in women.

Serum metabolomics reveals higher levels of polyunsaturated fatty acids in lepromatous leprosy: potential markers for susceptibility and pathogenesis

BACKGROUND

Leprosy is a disease of the skin and peripheral nervous system caused by the obligate intracellular bacterium Mycobacterium leprae. The clinical presentations of leprosy are spectral, with the severity of disease determined by the balance between the cellular and humoral immune response of the host. The exact mechanisms that facilitate disease susceptibility, onset and progression to certain clinical phenotypes are presently unclear. Various studies have examined lipid metabolism in leprosy, but there has been limited work using whole metabolite profiles to distinguish the clinical forms of leprosy.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study we adopted a metabolomics approach using high mass accuracy ultrahigh pressure liquid chromatography mass spectrometry (UPLC-MS) to investigate the circulatory biomarkers in newly diagnosed untreated leprosy patients. Sera from patients having bacterial indices (BI) below 1 or above 4 were selected, subjected to UPLC-MS, and then analyzed for biomarkers which distinguish the polar presentations of leprosy. We found significant increases in the abundance of certain polyunsaturated fatty acids (PUFAs) and phospholipids in the high-BI patients, when contrasted with the levels in the low-BI patients. In particular, the median values of arachidonic acid (2-fold increase), eicosapentaenoic acid (2.6-fold increase) and docosahexaenoic acid (1.6-fold increase) were found to be greater in the high-BI patients.

SIGNIFICANCE

Eicosapentaenoic acid and docosahexaenoic acid are known to exert anti-inflammatory properties, while arachidonic acid has been reported to have both pro- and anti-inflammatory activities. The observed increase in the levels of several lipids in high-BI patients may provide novel clues regarding the biological pathways involved in the immunomodulation of leprosy. Furthermore, these results may lead to the discovery of biomarkers that can be used to investigate susceptibility to infection, facilitate early diagnosis and monitor the progression of disease.

Plasma n-3 and n-6 fatty acids and the incidence of atrial fibrillation following coronary artery bypass graft surgery

BACKGROUND

The anti-inflammatory or anti-arrhythmic effects of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) may decrease the risk of postoperative atrial fibrillation (POAF), but interventional studies have yielded conflicting results. We examined the association between n-3 LC-PUFA and n-6 LC-PUFA in plasma phospholipids (PL) and POAF in patients undergoing coronary artery bypass grafting (CABG).

METHODS

A total of 125 patients undergoing CABG were enrolled in the study. The levels of fatty acids in PL were measured preoperatively and on the third postoperative day. The endpoint was defined as POAF lasting ≥5 min. The incidence of POAF was compared between quartiles of the level of each fatty acid in plasma PL by univariate and multivariable analysis.

RESULTS

The incidence of POAF was 49·6%. By univariate analysis, the incidence of POAF increased significantly with each higher quartile of pre- and postoperative docosahexaenoic acid (DHA) and diminished significantly with each higher quartile of pre- and postoperative arachidonic acid (AA). For postoperative total n-3 LC-PUFA, there was a significant U-curve relationship where the second quartile had the lowest incidence of POAF or 25·8%. In multivariable analysis, this U-curve relationship between n-3 LC-PUFA levels and POAF risk was not significant, whereas the association between POAF and DHA or AA remained statistically significant.

CONCLUSIONS

This study suggests that n-3 LC-PUFA supplements might prevent POAF in CABG patients with low baseline levels of these fatty acids in plasma PL, but may be harmful in those with high levels. AA may play an important role in electrophysiological processes.

Association between Ω3 and Ω6 fatty acid intakes and serum inflammatory markers in COPD

Dietary intake of polyunsaturated fatty acids, including omega-3 and omega-6, could modulate chronic obstructive pulmonary disease (COPD) persistent inflammation. We aimed to assess the relationship between dietary intake of omega-3 and omega-6 fatty acids and serum inflammatory markers in COPD. A total of 250 clinically stable COPD patients were included. Dietary data of the last 2 years were assessed using a validated food frequency questionnaire (122 items), which provided levels of three omega-3 fatty acids: docosahexaenoic acid, eicosapentaenoic acid and α-linolenic acid (ALA); and two omega-6 fatty acids: linoleic acid and arachidonic acid (AA). Inflammatory markers [C-reactive protein (CRP), interleukin (IL)-6, IL-8 and tumor necrosis factor alpha (TNFα)] were measured in serum. Fatty acids and inflammatory markers were dichotomised according to their median values, and their association was assessed using multivariate logistic regression. Higher intake of ALA (an anti-inflammatory omega-3 fatty acid) was associated with lower TNFα concentrations [adjusted odds ratio (OR)=0.46; P=.049]. Higher AA intake (a proinflammatory omega-6 fatty acid) was related to higher IL-6 (OR=1.96; P=.034) and CRP (OR=1.95; P=.039) concentrations. Therefore, this study provides the first evidence of an association between dietary intake of omega-3 and omega-6 fatty acids and serum inflammatory markers in COPD patients.

Secondhand smoke exposure and inflammatory markers in nonsmokers in the trucking industry

BACKGROUND

Few studies have directly assessed the association of secondhand smoke (SHS) with cardiovascular disease-related inflammatory markers, and the findings are inconsistent.

OBJECTIVES

We assessed the association between SHS exposure and the inflammatory markers high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and soluble intercellular adhesion molecule-1 (sICAM-1) in 199 nonsmoking U.S. trucking industry workers.

METHODS

Participants provided blood samples either by mail (blood drawn at local health care provider near home) or at the work site (blood drawn by research staff on-site) and completed a health and work history questionnaire at the time of blood draw. Exposure to SHS was measured by plasma cotinine concentrations. We used multivariate regression analyses to assess the associations between levels of cotinine and inflammatory markers.

RESULTS

The median cotinine level was 0.10 ng/mL (interquartile range, 0.04-0.23 ng/mL). The odds ratios of elevated hs-CRP (above highest CRP tertile, 1.5 mg/L) were 2.85 [95% confidence interval (CI), 1.03-7.89] for the high-cotinine group (> 0.215 ng/mL) and 2.80 (95% CI, 1.11-7.10) for the moderate-cotinine group (0.05-0.215 ng/mL), compared with the low-cotinine group (< 0.05 ng/mL), adjusting for age, sex, race, educational level, obesity, previous smoking history, job title, and medical history. Plasma cotinine levels were not associated with IL-6 or sICAM-1.

CONCLUSIONS

SHS exposure, as assessed by plasma cotinine, was positively associated with hs-CRP in this group of blue-collar workers. The strength of the association with hs-CRP depended on the cut points selected for analysis.

Associations of plasma phospholipid omega-6 and omega-3 polyunsaturated Fatty Acid levels and MRI measures of cardiovascular structure and function: the multiethnic study of atherosclerosis

Background. The association between plasma omega-6 fatty acids and cardiovascular disease (CVD) is unclear, and discrepancy remains concerning the cardiovascular benefit of the omega-3 fatty acid alpha-linolenic acid. Methods. Associations of plasma phospholipid fatty acid levels (arachidonic acid, linoleic acid, eicosapentaenoic acid, docosahexaenoic acid (DHA), and alpha-linolenic acid) with cardiac magnetic resonance imaging measures of left ventricular (LV) mass, LV volume, ejection fraction, stroke volume, and aortic distensibility were investigated in 1,274 adults. Results. Results of multivariate analysis showed no statistically significant associations of plasma omega-6 or omega-3 levels with cardiac magnetic resonance imaging measures. Stratification by gender revealed a positive association between DHA and LV mass in women (β = 1.89, P = 0.02; P interaction = 0.003) and a trend for a positive association between DHA and ejection fraction in men (β = 0.009, P = 0.05; P interaction = 0.03). Conclusion. Additional research is warranted to clarify the effects of plasma DHA on cardiac structure and function in women versus men.

Obesity modifies the association between plasma phospholipid polyunsaturated fatty acids and markers of inflammation: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND OBJECTIVE

Systemic inflammation is a well-known risk factor for diseases such as atherosclerosis and is augmented by the presence of obesity. In addition, it has been shown that inflammation may be negatively influenced by certain macronutrients, specifically the omega-3 and omega-6 fatty acids. The primary aim of this study is to determine whether obesity modifies the association between plasma phospholipid polyunsaturated fatty acids (PUFAs) and markers of inflammation and endothelial activation in Multi-Ethnic Study of Atherosclerosis (MESA) participants.

SUBJECTS

A sample of 2848 adults (25% African American, Chinese, Hispanic, and White) randomly selected from the MESA cohort.

MEASUREMENTS

Relative plasma PUFA concentrations were determined using gas chromatography-flame ionization detection. Levels of three inflammatory markers (high-sensitivity C-reactive protein, interleukin (IL)-6 and tumor necrosis factor-receptor 1) and two endothelial activation markers (soluble intercellular adhesion molecule-1 (sICAM-1) and E-selectin) were determined with enzyme immunoassays. Linear regression analysis was used to evaluate the relationship between these markers and plasma PUFAs.

RESULTS

Obesity modified the associations of linoleic acid (P(int)=0.01), dihomo-γ-linolenic (P(int)=0.07) and eicosapentaenoic acid (EPA) (P(int)=0.04) with sICAM-1 concentrations; in addition, obesity modified the association of IL-6 with dihomo-γ-linolenic (P(int)=0.01). In obese individuals, sICAM-1 was inversely related to EPA levels (P=0.02), but directly related to linoleic acid levels (P<0.001). Conversely, sICAM-1 was inversely related to linoleic acid levels in normal weight individuals (P=0.04). IL-6 concentrations were significantly and directly related to dihomo-γ-linolenic acid (DGLA) in normal weight (P=0.01) and obese participants (P<0.001), but the scale of increase across tertiles was greater in obese adults. Main effects of fatty acid and inflammatory marker associations are also reported.

CONCLUSION

The modifying effect of obesity on the association of plasma PUFAs with IL-6 and sICAM-1 suggests differences in fatty acid metabolism and may also have implications in dietary fatty acid intake for obese individuals, particularly for linoleic and EPAs. Further study is warranted to confirm and explain the strong associations of DGLA with inflammatory and endothelial activation markers.

Modulation of blood cell gene expression by DHA supplementation in hypertriglyceridemic men

Our previous study with docosahexaenoic acid (DHA) supplementation to hypertriglyceridemic men showed that DHA reduced several risk factors for cardiovascular disease, including the plasma concentration of inflammatory markers. To determine the effect of DHA supplementation on the global gene expression pattern, we performed Affymetrix GeneChip microarray analysis of blood cells [treated with lipopolysaccharide (LPS) or vehicle] drawn before and after the supplementation of DHA from the hypertriglyceridemic men who participated in that study. Genes that were significantly differentially regulated by the LPS treatment and DHA supplementation were identified. Differential regulation of 18 genes was then verified by quantitative real-time polymerase chain reaction (qRT-PCR). Both microarray and qRT-PCR data showed that DHA supplementation significantly suppressed the expression of low-density lipoprotein (LDL) receptor and cathepsin L1, both of which were also up-regulated by LPS. DHA supplementation also suppressed oxidized LDL (lectin-like) receptor 1 (OLR1). However, LPS did not induce OLR1 mRNA expression. Enrichment with Gene Ontology categories demonstrated that the genes related to transcription factor activity, immunity, host defense and inflammatory responses were inversely regulated by LPS and DHA. These results provide supporting evidence for the anti-inflammatory effects of DHA supplementation, and reveal previously unrecognized genes that are regulated by DHA and are associated with risk factors of cardiovascular diseases.

Polyunsaturated fatty acids and their effects on cardiovascular disease

Dietary polyunsaturated fatty acids (PUFAs) affect a wide variety of physiological processes. Much attention has been given to the n-3 PUFAs and their role in the prevention and treatment of cardiovascular disease, stemming from evidence obtained through a number of epidemiological studies and clinical trials. Investigators are now focused on elucidating the pathways and mechanisms for the biological action of n-3 PUFAs. Dietary intervention is recognized as a key measure in patient therapy and in the maintenance of human health in general. This review provides a summary of several important clinical trials, and while the exact modes of action of n-3 PUFA are not known, current viewpoints regarding the mechanisms of these fatty acids on atherosclerosis, circulating lipid profile, cell membranes, cell proliferation, platelet aggregation and cardiac arrhythmias are discussed.

[N-6 fatty acids and cardiovascular health: dietary intake recommendations]

Omega-6 polyunsaturated fatty acids (n-6 PUFA) are well known for their critical role in many physiological functions and reduce risks of cardiovascular disease (CVD). However, some argue that excessive consumption of n-6 PUFA may lead to adverse effects on health and therefore recommend reducing dietary n-6 PUFA intake or fixing an upper limit. Epidemiological studies show that n-6 PUFA dietary intake significantly lowers blood LDL-cholesterol levels. In addition, n-6 PUFA intake lower several cardiovascular risk factors such as blood pressure, inflammatory markers, haemostatic parameters and obesity. Data from prospective cohort and interventional studies converge towards a specific protective role of dietary n-6 PUFA intake, in particular linoleic acid, against CVD. In regards to studies examined in this narrative review, recommendation for n-6 PUFA intake above 5%, and ideally about 10% of total energy appears justified for the prevention of ischemic heart disease.

Pharmacology in health foods: effects of arachidonic acid and docosahexaenoic acid on the age-related decline in brain and cardiovascular system function

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are major constituents of cell membranes and play important roles in preserving physiological and psychological function. Recently, data from several studies have indicated that impairments in long-term potentiation (LTP), the process underlying plasticity in synaptic connections, are associated with a decrease in membrane ARA and DHA in aged rats; and treatment of aged rats with either of these polyunsaturated fatty acids (PUFAs) reverses age-related decrease in LTP and the decrease in membrane fatty acid concentration. This review focuses on our recent findings concerning the effects of ARA and DHA on the age-related decline in the function of the brain and cardiovascular system. ARA supplementation decreased P300 latency and increased P300 amplitude of event-related potentials in healthy elderly men. Cognitive impairments in patients with mild cognitive impairment (MCI) and patients with organic brain lesions were significantly improved with ARA and DHA supplementation. ARA and DHA supplementation also increased coronary flow velocity reserve in elderly individuals; this suggests beneficial effects of PUFAs on coronary microcirculation. In conclusion, ARA and DHA may be beneficial in preventing and/or improving age-related declines in brain and cardiovascular system function.

Associations of obesity with triglycerides and C-reactive protein are attenuated in adults with high red blood cell eicosapentaenoic and docosahexaenoic acids

BACKGROUND

N-3 fatty acids are associated with favorable, and obesity with unfavorable, concentrations of chronic disease risk biomarkers.

OBJECTIVE

We examined whether high eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid intakes, measured as percentages of total red blood cell (RBC) fatty acids, modify associations of obesity with chronic disease risk biomarkers.

METHODS

In a cross-sectional study of 330 Yup'ik Eskimos, generalized additive models (GAM) and linear and quadratic regression models were used to examine associations of BMI with biomarkers across RBC EPA and DHA categories.

RESULTS

Median (5th-95th percentile) RBC EPA and DHA were 2.6% (0.5-5.9%) and 7.3% (3.3-8.9%), respectively. In regression models, associations of BMI with triglycerides, glucose, insulin, C-reactive protein (CRP) and leptin differed significantly by RBC EPA and DHA. The GAM confirmed regression results for triglycerides and CRP: at low RBC EPA and RBC DHA, the predicted increases in triglycerides and CRP concentrations associated with a BMI increase from 25 to 35 were 99.5±45.3 mg/dl (106%) and 137.8±71.0 mg/dl (156%), respectively, for triglycerides and 1.2±0.7 mg/l (61%) and 0.8±1.0 mg/l (35%), respectively, for CRP. At high RBC EPA and RBC DHA, these predicted increases were 13.9±8.1 mg/dl (23%) and 12.0±12.3 mg/dl (18%), respectively, for triglycerides and 0.5±0.5 mg/l (50%) and -0.5±0.6 mg/l (-34%), respectively, for CRP.

CONCLUSIONS

In this population, high RBC EPA and DHA were associated with attenuated dyslipidemia and low-grade systemic inflammation among overweight and obese persons. This may help inform recommendations for n-3 fatty acid intakes in the reduction of obesity-related disease risk.

Polyunsaturated fatty acid intake and blood pressure in adolescents

Evidence that intake of polyunsaturated fatty acids (PUFAs) may modify blood pressure (BP) is generally limited to middle-aged or hypertensive populations. This study examined cross-sectional associations between BP and dietary intake of PUFAs in 814 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. Fatty acid intakes were assessed using 3-day diet records and resting BP was determined using multiple oscillometric readings. In multivariate regression models, systolic BP was inversely associated with intakes of polyunsaturated (b=-0.436, P<0.01), omega-3 (b=-2.47, P=0.02), omega-6 (b=-0.362, P=0.04) and long chain omega-3 fatty acids (b=-4.37, P=0.04) in boys. Diastolic BP and mean arterial pressure were inversely associated with intakes of long chain omega-3 fatty acids in boys (b=-3.93, P=0.01, b=-4.05, P=0.01, respectively). For specific long-chain omega-3s, significant inverse associations were observed between eicosapentaenoic acid (EPA) and docosahexaenoic acid, such as systolic BP decreasing by 4.7 mm Hg (95% CI -9.3 to -0.1) for a quarter gram increase in EPA, but no significant associations were observed with docosapentaenoic acid. No significant associations were observed in girls, or with the omega-6 to omega-3 ratio. Our results suggest that gender may moderate relationships between fatty acid intake and BP in adolescence.

Dose-response effects of omega-3 fatty acids on triglycerides, inflammation, and endothelial function in healthy persons with moderate hypertriglyceridemia

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to reduce cardiovascular mortality at a dose of ≈1 g/d. Studies using higher doses have shown evidence of reduced inflammation and improved endothelial function. Few studies have compared these doses.

OBJECTIVE

The objective of this study was to compare the effects of a nutritional dose of EPA+DHA (0.85 g/d) with those of a pharmaceutical dose (3.4 g/d) on serum triglycerides, inflammatory markers, and endothelial function in healthy subjects with moderately elevated triglycerides.

DESIGN

This was a placebo-controlled, double-blind, randomized, 3-period crossover trial (8 wk of treatment, 6 wk of washout) that compared the effects of 0.85 and 3.4 g EPA+DHA/d in 23 men and 3 postmenopausal women with moderate hypertriglyceridemia (150-500 mg/dL).

RESULTS

The higher dose of EPA+DHA lowered triglycerides by 27% compared with placebo (mean ± SEM: 173 ± 17.5 compared with 237 ± 17.5 mg/dL; P = 0.002), whereas no effect of the lower dose was observed on lipids. No effects on cholesterol (total, LDL, and HDL), endothelial function [as assessed by flow-mediated dilation, peripheral arterial tonometry/EndoPAT (Itamar Medical Ltd, Caesarea, Israel), or Doppler measures of hyperemia], inflammatory markers (interleukin-1β, interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein), or the expression of inflammatory cytokine genes in isolated lymphocytes were observed.

CONCLUSION

The higher dose (3.4 g/d) of EPA+DHA significantly lowered triglycerides, but neither dose improved endothelial function or inflammatory status over 8 wk in healthy adults with moderate hypertriglyceridemia. The trial was registered at clinicaltrials.gov as NCT00504309.

Estimation of the contribution of biomarkers of different metabolic pathways to risk of type 2 diabetes

The contribution of different biological pathways to the development of type 2 diabetes was quantified in a case-cohort design based on circulating blood biomarkers from participants aged 35-65 years in the EPIC-Potsdam Study. The analytic sample included 613 participants with incident diabetes and 1965 participants without diabetes. The proportion that each biomarker contributed to the risk of diabetes was quantified using effect decomposition method. Summarized risk of each biomarker was estimated by an index based on quintiles of gamma-glutamyltransferase (GGT), HDL-cholesterol, hs-CRP, and adiponectin. Cox proportional hazard regression was used to estimate relative risks adjusted for age, sex, body mass index, waist-circumference, education, sport activity, cycling, occupational activity, smoking, alcohol intake, and consumptions of red meat, coffee and whole grain bread. Adiponectin explained a total of 32.1% (CI = 16.8, 49.1%) of the risk related to index. For the other biomarkers the corresponding proportions were 23.5% (CI = 10.1, 37.8%) by HDL-cholesterol, 21.5% (CI = 11.5, 32.8%) by GGT, and 15.5% (CI = 4.44, 27.3%) by hs-CRP. The results support the hypothesis that the different biological pathways reflected by GGT, HDL-cholesterol, hs-CRP and adiponectin independent from each other contribute to the risk of type 2 diabetes. Of these pathways the highest contribution was observed for adiponectin which contributed one-third to the risk and that equal proportion was contributed by GGT and HDL-cholesterol, although the contribution of inflammation was lower.

Fatty acid consumption and risk of fracture in the Women's Health Initiative

BACKGROUND

Fatty acids (FAs) may be important dietary components that modulate osteoporotic fracture risk.

OBJECTIVE

The objective was to examine FA intake in relation to osteoporotic fractures.

DESIGN

The participants were postmenopausal women enrolled in the Women's Health Initiative (n = 137,486). Total fractures were identified by self-report; hip fractures were confirmed by medical record review. FA intake was estimated from baseline food-frequency questionnaires and standardized to total caloric intake. No data on omega-3 (n-3) FA supplements were available. Cox proportional hazard models were constructed to estimate risk of fracture.

RESULTS

Higher saturated FA consumption was associated with higher hip fracture risk [quartile 4 multivariate-adjusted hazard ratio (HR): 1.31; 95% CI: 1.11, 1.55; P for trend = 0.001]. Lower total fracture risk was associated with a higher monounsaturated FA intake (quartile 3 HR: 0.94; 95% CI: 0.89, 0.98; P for trend = 0.050) and polyunsaturated FA intake (quartile 4 HR: 0.95; 95% CI: 0.90, 0.99; P for trend = 0.019). Unexpectedly, higher consumption of marine n-3 FAs was associated with greater total fracture risk (quartile 4 HR: 1.07; 95% CI: 1.02, 1.12; P for trend = 0.010), whereas a higher n-6 FA intake was associated with a lower total fracture risk (quartile 4 HR: 0.94; 95% CI: 0.89, 0.98; P for trend 0.009).

CONCLUSIONS

These results suggest that saturated FA intake may significantly increase hip fracture risk, whereas monounsaturated and polyunsaturated FA intakes may decrease total fracture risk. In postmenopausal women with a low intake of marine n-3 FAs, a higher intake of n-6 FAs may modestly decrease total fracture risk. This trial was registered at clinicaltrials.gov as NCT00000611.

Relation of omega-3 fatty acid and dietary fish intake with brachial artery flow-mediated vasodilation in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

The relation between dietary fish intake and brachial artery measures, including brachial artery flow-mediated dilation (FMD), has not been well established across sex and racial-ethnic groups.

OBJECTIVE

We hypothesized that consumption of nonfried fish and plasma phospholipid measures of long-chain omega-3 (n-3) fatty acids would be positively associated with larger FMD in men and women across racial-ethnic groups.

DESIGN

We investigated cross-sectional associations of brachial artery measures with fish intake (ascertained with a food-frequency questionnaire) and plasma phospholipid omega-3 concentrations in 3045 adults, aged 45-84 y, who were free of clinical cardiovascular disease.

RESULTS

In overall multivariate-adjusted analyses, there were no significant associations between fish intake or any brachial artery measures. However, when stratified by sex, there was an association between the highest quartile of nonfried fish consumption and a 0.10-mm lower (1 SD) brachial artery diameter in men (P = 0.01) and a 0.27% smaller FMD in women (P = 0.02) compared with the lowest quartile of nonfried fish intake in each respective sex strata. When stratified by race-ethnicity and race-ethnicity by sex, additional heterogeneity was noted, but results were difficult to interpret because of small sample sizes. Plasma phospholipid omega-3 concentrations showed a similar directionality of association with brachial artery measures observed for nonfried fish consumption, although statistical significance was not achieved in fully adjusted models.

CONCLUSION

This study indicates that the association between nonfried fish intake and baseline brachial artery size varies by sex, with suggestive evidence of sex differences in the association between nonfried fish intake and FMD.

n-3 polyunsaturated fatty acids prevents atrial fibrillation by inhibiting inflammation in a canine sterile pericarditis model

OBJECTIVE

It has been recently reported that atrial fibrillation (AF) is associated with inflammation and inflammatory cytokines, and n-3 polyunsaturated fatty acids (PUFAs) might be of anti-inflammatory effects. This study was to evaluate the anti-inflammatory effect of PUFAs on AF in a canine sterile pericarditis model.

METHODS

20 dogs were randomly assigned to two groups: control group (10 dogs) and PUFA treatment group (10 dogs), in which sterile pericarditis was created by open-chest operation. PUFAs were administered orally (2g/day) 4 weeks before the operation till the end of the study. Before and 2 days after the operation, CRP, IL-6, TNF-α levels, the inducibility and maintenance of AF, the atrial effective refractory period (AERPs), and intra-atrial conduction time were determined.

RESULTS

Before the operation, there were no significant differences in any of the parameters between the two groups. On the second postoperative day, the PUFA group had a lower CRP level (7.6 ± 0.5 vs. 11.7 ± 1.3mg/dl, P<0.0001), a lower IL-6 level (112.0 ± 37.3 vs. 142.0 ± 19.6 pg/ml, P<0.01), a lower TNF-α level (83.3 ± 8.5 vs. 112.4 ± 8.2 pg/ml, P<0.0001), a less AF inducibility (percentage of burst attempts leading to AF episodes: 11 ± 7.4 vs. 28 ± 10.3, P<0.001) and maintenance [median AF duration: 1105 s (655.8-1406.5) vs. 2516.5 s (1187-3361), P<0.05], a longer AERP (133.4 ± 4.1 vs. 129.8 ± 4.3 ms, P<0.05), and a shorter intra-atrial conduction time (46.6 ± 4.4 vs. 51.9 ± 4.8 ms, P<0.05) than the control group.

CONCLUSIONS

Dietary n-3 PUFA supplementation attenuates the inducibility and maintenance of AF in the sterile pericarditis model by reducing the production of proinflammatory cytokines.

Circulating C-reactive protein concentrations and risks of colon and rectal cancer: a nested case-control study within the European Prospective Investigation into Cancer and Nutrition

The authors investigated associations between serum C-reactive protein (CRP) concentrations and colon and rectal cancer risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (1992-2003) among 1,096 incident cases and 1,096 controls selected using risk-set sampling and matched on study center, age, sex, time of blood collection, fasting status, menopausal status, menstrual cycle phase, and hormone replacement therapy. In conditional logistic regression with adjustment for education, smoking, nutritional factors, body mass index, and waist circumference, CRP showed a significant nonlinear association with colon cancer risk but not rectal cancer risk. Multivariable-adjusted relative risks for CRP concentrations of > or = 3.0 mg/L versus <1.0 mg/L were 1.36 (95% confidence interval (CI): 1.00, 1.85; P-trend = 0.01) for colon cancer and 1.02 (95% CI: 0.67, 1.57; P-trend = 0.65) for rectal cancer. Colon cancer risk was significantly increased in men (relative risk = 1.74, 95% CI: 1.11, 2.73; P-trend = 0.01) but not in women (relative risk = 1.06, 95% CI: 0.67, 1.68; P-trend = 0.13). Additional adjustment for C-peptide, glycated hemoglobin, and high density lipoprotein cholesterol did not attenuate these results. These data provide evidence that elevated CRP concentrations are related to a higher risk of colon cancer but not rectal cancer, predominantly among men and independently of obesity, insulin resistance, and dyslipidemia.

Fat intake interacts with polymorphisms of Caspase9, FasLigand and PPARgamma apoptotic genes in modulating Crohn's disease activity

BACKGROUND & AIMS

Crohn's disease (CD) is a multifactorial disease where resistance to apoptosis is one major defect. Also, dietary fat intake has been shown to modulate disease activity. We aimed to explore the interaction between four single nucleotide polymorphisms (SNPs) in apoptotic genes and dietary fat intake in modulating disease activity in CD patients.

METHODS

Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) techniques were used to analyze Caspase9+93C/T, FasLigand-843C/T, Peroxisome Proliferator-Activated Receptor gamma+161C/T and Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNPs in 99 patients with CD and 116 healthy controls. Interactions between SNPs and fat intake in modulating disease activity were analyzed using regression analysis.

RESULTS

None of the polymorphisms analyzed influenced disease susceptibility and/or activity, but a high intake of total, saturated and monounsaturated fats and a higher ratio of n-6/n-3 polyunsaturated fatty acids(PUFA), was associated with a more active phenotype (p < 0.05). We observed that the detrimental effect of a high intake of total and trans fat was more marked in wild type carriers of the Caspase9+93C/T polymorphism [O.R(95%CI) 4.64(1.27-16.89) and O.R(95%CI) 4.84(1.34-17.50)]. In the Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNP, we also observed that a high intake of saturated and monounsaturated fat was associated to a more active disease in wild type carriers [OR(95%CI) 4.21(1.33-13.26) and 4.37(1.52-12.51)]. Finally, a high intake of n-6 PUFA was associated with a more active disease in wild type carriers for the FasLigand-843C/T polymorphism [O.R(95%CI) 5.15(1.07-24.74)].

CONCLUSIONS

To our knowledge, this is the first study to disclose a synergism between fat intake and SNPs in apoptotic genes in modulating disease activity in CD patients.

High habitual dietary alpha-linolenic acid intake is associated with decreased plasma soluble interleukin-6 receptor concentrations in male twins

BACKGROUND

alpha-Linolenic acid (ALA) is associated with a low risk of cardiovascular disease; however, the underlying mechanism is not completely known.

OBJECTIVE

The objective was to examine whether habitual dietary ALA intake is associated with plasma concentrations of inflammatory biomarkers after control for shared genetic and common environmental factors.

DESIGN

We cross-sectionally studied 353 middle-aged male twins. Habitual diet was assessed with the Willett food-frequency questionnaire. Fasting plasma concentrations of interleukin-6 (IL-6) and its soluble receptor (sIL-6R), high-sensitivity C-reactive protein (hsCRP), and tumor necrosis factor-alpha (TNF-alpha) were measured. Linear mixed-effect regression analysis was used to partition the overall association into within- and between-pair associations.

RESULTS

A 1-g increment in habitual dietary ALA intake was associated with 11.0% lower concentrations of sIL-6R (P = 0.004) but not of IL-6 (P = 0.31), TNF-alpha (P = 0.16), or hsCRP (P = 0.36) after adjustment for energy intake, nutritional factors, known cardiovascular disease risk factors, and medications. After further control for shared genetic and common environmental factors by comparison of brothers within a twin pair, a twin with a 1-g higher ALA intake was likely to have 10.9% (95% CI: 3.7%, 17.6%; P = 0.004) lower sIL-6R concentrations than his co-twin with a low intake, whereas ALA intake was not significantly associated with plasma concentrations of IL-6, TNF-alpha, or hsCRP. These results were validated by using 1000 bootstrap samples.

CONCLUSIONS

Habitual dietary ALA intake is inversely associated with plasma sIL-6R concentrations independent of shared genetic and common environmental influences. Lowering sIL-6R may be a mechanism underlying the cardioprotective properties of habitual dietary ALA. This study was registered at clinicaltrials.gov as NCT00017836.

Effects of weight loss and seafood consumption on inflammation parameters in young, overweight and obese European men and women during 8 weeks of energy restriction

BACKGROUND/OBJECTIVES

In vitro studies have shown that long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs) can affect inflammation; however, results from intervention studies in overweight or obese individuals are contradicting. The aim of this study was to investigate the effects of weight loss and seafood consumption on inflammation parameters during energy restriction.

SUBJECTS/METHODS

In this 8-week intervention trial, 324 subjects (aged 20-40 years, body mass index 27.5-32.5 kg/m(2) from Iceland, Spain and Ireland) were randomized to one of four energy-restricted diets (-30% relative to estimated requirements): salmon (3 x 150 g/week, 2.1 g LC n-3 PUFA per day); cod (3 x 150 g/week, 0.3 g LC n-3 PUFA per day); fish oil capsules (1.3 g LC n-3 PUFA per day); and control (sunflower oil capsules, no seafood). Body weight, high-sensitivity C-reactive protein (CRP), interleukin-6 (IL-6), glutathione reductase and prostaglandin F2 alpha (PGEF2alpha) were measured at baseline and end point.

RESULTS

Subjects experienced weight loss (-5.2+/-3.2 kg, P<0.001). Taken together for all subjects, there were significant decreases in all inflammation parameters. On a group level, salmon consumption was most effective, three of the four inflammation parameters decreased in the salmon group (high-sensitivity CRP=-32.0%; IL-6=-18.4%; PGEF2alpha=-18.5%; all P<0.05). Cod consumption decreased high-sensitivity CRP and IL-6 (-21.5 and -10.8%, respectively, both P<0.05). Changes in the other two groups were not significant, which can be partly explained by the large s.d.

CONCLUSIONS

The mean concentrations of inflammation parameters decreased during a period of weight loss and dietary intervention. In our study, salmon consumption was most effective, three of the four measured inflammation parameters decreased significantly in the salmon group.

The relationship between dietary lipids and cognitive performance in an elderly population

Epidemiological studies on the association between diet and cognitive function suggested a possible role of dietary fatty acids in cognitive decline. The aim of the present study was to examine whether intake of different types of fatty acids is associated with cognitive status. A cohort of 304 (127 men and 177 women) institutionalized elderly people, with a mean age of 75.3 +/- 6.7 years, were studied. Subjects were evaluated for global cognitive functions (Mini-Mental State Examination [MMSE], Spanish version). Fatty acid intake was assessed with a semi-quantitative food frequency questionnaire. Intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found to be predictors of cognitive impairment as they were negatively associated with the MMSE score. In accordance with this, fish intake was inversely associated with cognitive impairment. On the contrary, the n-6/n-3 polyunsaturated fatty acid ratio was positively related to the MMSE score. These results could not be explained by differences in age, sex, education, smoking behaviour, inactivity, alcohol, institution or energy intake. We suggest that consumption of EPA and DHA should be encouraged for reducing the risk of cognitive impairment and subsequently disability in elderly people.

n-6 Fatty acids and cardiovascular health: a review of the evidence for dietary intake recommendations

n-6 PUFA are well known for their critical role in many physiological functions and seem to reduce risks of CHD. However, some argue that excessive consumption of n-6 PUFA may lead to adverse effects on health and therefore recommend reducing dietary n-6 PUFA intake or fixing an upper limit. In this context, the present work aimed to review evidence on the link between n-6 PUFA and risks of CVD. Epidemiological studies show that n-6 PUFA dietary intake significantly lowers blood LDL-cholesterol levels. In addition, n-6 PUFA intake does not increase several CVD risk factors such as blood pressure, inflammatory markers, haemostatic parameters and obesity. Data from prospective cohort and interventional studies converge towards a specific protective role of dietary n-6 PUFA intake, in particular linoleic acid, against CVD. n-6 PUFA benefits are even increased when SFA intake is also reduced. In regards to studies examined in this narrative review, recommendation for n-6 PUFA intake above 5 %, and ideally about 10 %, of total energy appears justified.

Stress, food, and inflammation: psychoneuroimmunology and nutrition at the cutting edge

Inflammation is the common link among the leading causes of death. Mechanistic studies have shown how various dietary components can modulate key pathways to inflammation, including sympathetic activity, oxidative stress, transcription factor nuclear factor-kappaB activation, and proinflammatory cytokine production. Behavioral studies have demonstrated that stressful events and depression can also influence inflammation through these same processes. If the joint contributions of diet and behavior to inflammation were simply additive, they would be important. However, several far more intriguing interactive possibilities are discussed: stress influences food choices; stress can enhance maladaptive metabolic responses to unhealthy meals; and diet can affect mood as well as proinflammatory responses to stressors. Furthermore, because the vagus nerve innervates tissues involved in the digestion, absorption, and metabolism of nutrients, vagal activation can directly and profoundly influence metabolic responses to food, as well as inflammation; in turn, both depression and stress have well-documented negative effects on vagal activation, contributing to the lively interplay between the brain and the gut. As one example, omega-3 fatty acid intake can boost mood and vagal tone, dampen nuclear factor-kappaB activation and responses to endotoxin, and modulate the magnitude of inflammatory responses to stressors. A better understanding of how stressors, negative emotions, and unhealthy meals work together to enhance inflammation will benefit behavioral and nutritional research, as well as the broader biomedical community.

Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Reduced saturated fat (SFA) consumption is recommended to reduce coronary heart disease (CHD), but there is an absence of strong supporting evidence from randomized controlled trials (RCTs) of clinical CHD events and few guidelines focus on any specific replacement nutrient. Additionally, some public health groups recommend lowering or limiting polyunsaturated fat (PUFA) consumption, a major potential replacement for SFA.

METHODS AND FINDINGS

We systematically investigated and quantified the effects of increased PUFA consumption, as a replacement for SFA, on CHD endpoints in RCTs. RCTs were identified by systematic searches of multiple online databases through June 2009, grey literature sources, hand-searching related articles and citations, and direct contacts with experts to identify potentially unpublished trials. Studies were included if they randomized participants to increased PUFA for at least 1 year without major concomitant interventions, had an appropriate control group, and reported incidence of CHD (myocardial infarction and/or cardiac death). Inclusions/exclusions were adjudicated and data were extracted independently and in duplicate by two investigators and included population characteristics, control and intervention diets, follow-up duration, types of events, risk ratios, and SEs. Pooled effects were calculated using inverse-variance-weighted random effects meta-analysis. From 346 identified abstracts, eight trials met inclusion criteria, totaling 13,614 participants with 1,042 CHD events. Average weighted PUFA consumption was 14.9% energy (range 8.0%-20.7%) in intervention groups versus 5.0% energy (range 4.0%-6.4%) in controls. The overall pooled risk reduction was 19% (RR = 0.81, 95% confidence interval [CI] 0.70-0.95, p = 0.008), corresponding to 10% reduced CHD risk (RR = 0.90, 95% CI = 0.83-0.97) for each 5% energy of increased PUFA, without evidence for statistical heterogeneity (Q-statistic p = 0.13; I(2) = 37%). Meta-regression identified study duration as an independent determinant of risk reduction (p = 0.017), with studies of longer duration showing greater benefits.

CONCLUSIONS

These findings provide evidence that consuming PUFA in place of SFA reduces CHD events in RCTs. This suggests that rather than trying to lower PUFA consumption, a shift toward greater population PUFA consumption in place of SFA would significantly reduce rates of CHD. Please see later in the article for the Editors' Summary.

Adjuvant therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging US population and affecting more than 2.3 million people. Current approaches for managing AF are rate- or rhythm-control strategies, both using anti-thrombotic therapy to prevent thromboembolism. While great advances have been made in understanding the pathophysiology of AF, few new strategies have shown promise in prevention or treatment of AF. Recent data suggest that non-antiarrhythmic medication may be useful in modifying the substrate that allows AF precipitation and perpetuation. This article reviews the data on the role of these agents in the prevention and management of AF as an adjunct to standard therapy.

Associations of very high intakes of eicosapentaenoic and docosahexaenoic acids with biomarkers of chronic disease risk among Yup'ik Eskimos

BACKGROUND

Few studies have examined the associations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with biomarkers of chronic disease risk in populations with high intakes.

OBJECTIVE

We examined the associations of red blood cell (RBC) EPA and DHA, as percentages of total fatty acids, with biomarkers of chronic disease risk across a wide range of EPA and DHA intakes.

DESIGN

In a cross-sectional study of 357 Yup'ik Eskimos, generalized additive models were used to plot covariate-adjusted associations of EPA and DHA with chronic disease biomarkers. Linear regression models were used to test for the statistical significance of these associations.

RESULTS

Means (5th-95th percentiles) for RBC EPA and DHA were 2.8% (0.5-5.9%) and 6.8% (3.3-9.0%), respectively. Associations of EPA and DHA were inverse and linear for triglycerides (beta +/- SE = -0.10 +/- 0.01 and -0.05 +/- 0.01, respectively) and positive and linear for HDL cholesterol (beta +/- SE = 2.0 +/- 0.5 and 0.9 +/- 0.6, respectively) and apolipoprotein A-I (beta +/- SE = 2.6 +/- 0.8 and 1.7 +/- 0.8, respectively). Positive linear associations of DHA with LDL and total cholesterol (beta +/- SE = 7.5 +/- 1.4 and 6.80 +/- 1.57, respectively) were observed; for EPA, these associations were nonlinear and restricted to concentrations approximately <5% of total fatty acids. Associations of EPA and DHA with C-reactive protein were inverse and nonlinear: for EPA, the association appeared stronger at concentrations approximately >3% of total fatty acids; for DHA, it was observed only at concentrations approximately >7% of total fatty acids.

CONCLUSION

Increasing EPA and DHA intakes to amounts well above those consumed by the general US population may have strong beneficial effects on chronic disease risk.

Inflammatory effects of nutritional stimuli: further support for the need for a big picture approach to tackling obesity and chronic disease

The discovery of a form of low-grade systemic inflammation (called 'metaflammation'), and the close evolutionary link between the immune and metabolic systems, poses questions about the supposed antigens (inducers) of such an immune reaction. Initially, this was thought to be mediated through obesity. However, we have identified a number of lifestyle or environmentally related inducers that may cause metaflammation, even in the absence of obesity. In this paper, the third of a series linking obesity with broad environmental and evolutionary factors, we identify nutritional stimuli with evidence of an involvement in metaflammation. From this we propose that components of certain foods and beverages with which humans have not evolved, are more often the inducers of an inflammatory effect in the body than those with which humans have become more familiar, and to which a neutral, or anti-inflammatory response may be expected to have developed. The implications of such a finding are considered in relation to broader aspects of the environment, economic growth, policy change and current global financial issues.

Unsaturated fatty acids are inversely associated and n-6/n-3 ratios are positively related to inflammation and coagulation markers in plasma of apparently healthy adults

BACKGROUND

Blood lipids and inflammatory markers levels have been associated with the development and progression of atherosclerosis. As the association of inflammatory markers with plasma fatty acids has not been extensively evaluated and understood, we sought to investigate the associations between dietary and plasma fatty acids with various inflammation and coagulation markers.

METHODS

High sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), fibrinogen, and homocysteine were measured in serum of 374 free-living, healthy men and women, randomly selected from the ATTICA's study database. Total plasma fatty acids were determined by gas chromatography. Dietary fatty acids were assessed through a semi-quantitative FFQ.

RESULTS

Multi-adjusted regression analyses revealed that plasma n-3 fatty acids were inversely associated with CRP, IL-6 and TNF-alpha; plasma n-6 fatty acids were inversely associated with CRP, IL-6 and fibrinogen; monounsaturated fatty acids were inversely associated with CRP and IL-6 (all p-values<0.05). Interestingly, the n-6/n-3 ratios exhibited the strongest positive correlations with all the markers studied. No associations were observed between dietary fatty acids and the investigated markers.

CONCLUSIONS

Measurements of total plasma fatty acids could provide insights into the relationships between diet and atherosclerotic disease. Moreover, the n-6/n-3 ratio may constitute a predictor of low-grade inflammation and coagulation.

Plasma free fatty acid patterns and their relationship with CVD risk in a male middle-aged population

BACKGROUND/OBJECTIVES

The role of individual fatty acids in the development of cardiovascular disease (CVD) is well established, but the effects of an overall pattern of fatty acids in CVD risk has yet to be elucidated. Circulating fatty acid levels are related to metabolic disturbances associated with the metabolic syndrome and CVD, due to disturbances in the activity of enzymes that catalyse fatty acid desaturation (Delta-desaturases). Therefore, we determined patterns of fatty acids and estimated desaturase activity in plasma and analysed how these patterns were related to a 10-year CVD risk estimates in a middle-aged male population in Northern Ireland.

SUBJECTS/METHODS

Principal components analysis (PCA) was performed for defining fatty acid patterns in 379 men aged 30-49 years. Logistic regression analyses were then carried out for analysing the relationship between these fatty acid patterns and the 10-year CVD risk estimates.

RESULTS

The PCA generated three high fatty acid patterns: high saturated fatty acid (SFA), high omega 3 fatty acid (omega 3) and high monosaturated fatty acid (MNFA). Results from logistic regression analyses show that a 1 s.d. increase in the SFA pattern score was significantly and positively associated with an increase in the 10-year CVD risk category (odds ratio 1.71, 95% confidence interval 1.33-2.21, P<0.0001) even after adjustment for lifestyle factors. There were no significant relationships between the other two pattern scores and the 10-year CVD risk.

CONCLUSIONS

An unhealthy fatty acid pattern representing both dietary intake and in vivo fatty acid metabolism is related to the 10-year CVD risk estimates and provide evidence that, as with dietary patterns, the synergistic effect of multiple fatty acids may be more important in relation to the development of CVD risk.

A new approach for decreasing postoperative peritoneal adhesions: preventing peritoneal trauma with soybean oil

BACKGROUND

Covering peritoneal surfaces with soybean oil may decrease peritoneal adhesions by preventing peritoneal trauma.

METHOD(S)

Forty female albino Wistar rats were divided into four equal groups. In Group 1, soybean oil only (0.1 ml) was injected into the peritoneal cavity. In Group 2, an untreated adhesion model was generated. In Group 3, an adhesion model was generated, followed by covering the area with soybean oil (0.1 ml). In Group 4, the area was first covered with soybean oil (0.1 ml) followed by generation of an adhesion model. All rats were sacrificed on postoperative day 10, and adhesions were scored.

RESULTS

The mean macroscopic adhesion scores in Groups 1, 2, 3, and 4 were 0.0 +/- 0.0, 2.90 +/- 0.21, 1.90 +/- 0.94, and 0.50 +/- 0.71, respectively. The Group 4 score differed significantly from that of Group 2 (p <. 001), but was not different from that of Group 1 or 3 (p >. 05).

DISCUSSION

Soybean oil can effectively decrease adhesion formation if applied before peritoneal trauma.