Beyond the Mediterranean Diet: The Role of Omega‐3 Fatty Acids in the Prevention of Coronary Heart Disease

The Effects of the Mediterranean Diet on Health and Gut Microbiota

The Mediterranean Diet (MD) is plant-based and consists of multiple daily portions of vegetables, fruit, cereals, and olive oil. Although there are challenges with isolating the MD from the typical Mediterranean lifestyle and culture (including prolonged 'social' meals and siestas), much evidence supports the health benefits of the MD that include improved longevity, reduced metabolic risk of Diabetes Mellitus, obesity, and Metabolic Syndrome, reduced risk of malignancy and cardiovascular disease, and improved cognitive function. The MD is also associated with characteristic modifications to gut microbiota, mediated through its constituent parts (primarily dietary fibres, extra virgin olive oil, and polyunsaturated fatty acids [including ω-3]). These include enhanced growth of species that produce short-chain fatty acids (butyrate), such as Clostridium leptum and Eubacterium rectale, enhanced growth of Bifidobacteria, Bacteroides, and Faecalibacterium prausnitzii species, and reduced growth of Firmicutes and Blautia species. Such changes in gut microbiota are known to be associated favourably with inflammatory and oxidative status, propensity for malignancy and overall metabolic health. A key challenge for the future is to explore the extent to which the health benefits of the MD are mediated by such changes to gut microbiota. The MD confers both health and environmental benefits. Adoption of the MD should perhaps be encouraged and facilitated more generally and not just restricted to populations from Mediterranean regions. However, there are key challenges to this approach that include limited perennial availability of the constituent parts of the MD in some non-Mediterranean regions, intolerability of a high-fibre diet for some people, and potential cultural disconnects that juxtapose some traditional (including Western) diets with the MD.

Probiotics, bioactive compounds and dietary patterns for the effective management of hyperuricemia: a review

Hyperuricemia is closely linked with an increased risk of developing hypertension, diabetes, renal failure and other metabolic syndromes. Probiotics, bioactive compounds and dietary patterns are safe cost-efficient ways to control hyperuricemia, whereas comprehensive reviews of their anti-hyperuricemic mechanisms are limited. This review summarizes the roles of probiotics, bioactive compounds and dietary patterns in treating hyperuricemia and critically reviews the possible mechanisms by which these interventions exert their activities. The dietary patterns are closely related to the occurrence of hyperuricemia through the indirect action of gut microbiota or the direct effects of host purine metabolism. The Mediterranean and Dietary Approaches to Stop Hypertension diets help reduce serum uric acid concentrations and thus prevent hyperuricemia. Meanwhile, probiotics alleviate hyperuricemia by ways of absorbing purine, restoring gut microbiota dysbiosis and inhibiting xanthine oxidase (XO) activity. Bioactive compounds such as polyphenols, peptides and alkaloids exert various anti-hyperuricemic effects, by regulating urate transporters, blocking the active sites of XO and inhibiting the toll-like receptor 4/nuclear factor kappa B signaling pathway and NOD-, LRR- and pyrin domain-containing protein 3 signaling pathway. This review will assist people with hyperuricemia to adopt a healthy diet and contribute to the application of natural products with anti-hyperuricemic activity.

Conditional Recommendations for Specific Dietary Ingredients as an Approach to Chronic Musculoskeletal Pain: Evidence-Based Decision Aid for Health Care Providers, Participants, and Policy Makers

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular for a wide range of pain conditions, decisions to use supplements are often driven by information that is not evidence-based. This work evaluates whether the current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. A decision table was constructed to make evidence-informed judgments across factors required for decision-making, and recommendations were made for practice and self-care use.

RESULTS

Nineteen dietary ingredients were included. Conditional evidence-based recommendations were made for the use of avocado soybean unsaponifiables, capsaicin, curcuma, ginger, glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D. In these cases, desirable effects outweighed undesirable effects, but there was uncertainty about the trade-offs, either because the evidence was low quality or because benefits and downsides were closely balanced.

CONCLUSIONS

The evidence showed that certain dietary ingredients, when taken as part of a balanced diet and/or as a supplement (e.g., pill, tablet, capsule, cream), may alleviate musculoskeletal pain with no to minimal risk of harm. This finding emphasizes and reinforces the critical importance of shared decision-making between Operators and their health care providers.

Plasma, Urine, and Adipose Tissue Biomarkers of Dietary Intake Differ Between Vegetarian and Non-Vegetarian Diet Groups in the Adventist Health Study-2

BACKGROUND

Differences in food composition, nutrient intake, and various health outcomes have been reported for vegetarians and non-vegetarians in the Adventist Health Study-2 (AHS-2) cohort.

OBJECTIVE

We sought to determine whether biomarkers of dietary intake also differed between individuals classified as vegetarian (vegan, lacto-ovo-vegetarian, pesco-vegetarian, semi-vegetarian) and non-vegetarians based on patterns of consumption of meat, dairy, and eggs.

METHODS

Fasting plasma, overnight urine, and adipose tissue samples were collected from a representative subset of AHS-2 participants classified into 5 diet groups (vegan, lacto-ovo-vegetarian, pesco-vegetarian, semi-vegetarian, non-vegetarian) who also completed food-frequency questionnaires. Diet-related biomarkers including carotenoids, isoflavones, enterolactone, saturated and polyunsaturated fatty acids, and vitamins were analyzed in 840 male and female participants. Multiple linear regression was used to examine the association between diet pattern and biomarker abundance, comparing each of 4 vegetarian dietary groups to non-vegetarians, and adjusted mean values were calculated. Bonferroni correction was applied to control for multiple testing.

RESULTS

Vegans had higher plasma total carotenoid concentrations (1.6-fold, P < 0.0001), and higher excretion of urinary isoflavones (6-fold, P < 0.0001) and enterolactone (4.4-fold) compared with non-vegetarians. Vegans had lower relative abundance of saturated fatty acids including myristic, pentadecanoic, palmitic, and stearic acids (P < 0.0001). Vegans had higher linoleic acid (18:2ω-6) relative to non-vegetarians (23.3% compared with 19.1%) (P < 0.0001), and a higher proportion of total ω-3 fatty acids (2.1% compared with 1.6%) (P < 0.0001). Results overall were similar but less robust for lacto-ovo- and pesco-vegetarians. 1-Methylhistidine was 92% lower in vegans, and lower in lacto-ovo- and pesco-vegetarians by 90% and 80%, respectively, relative to non-vegetarians (P < 0.0001).

CONCLUSION

AHS-2 participants following vegan, and lacto-ovo- or pesco-vegetarian diet patterns have significant differences in plasma, urine, and adipose tissue biomarkers associated with dietary intakes compared with those who consume a non-vegetarian diet. These findings provide some validation for the prior classification of dietary groups within the AHS-2 cohort.

Metabolic syndrome, Mediterranean diet, and polyphenols: Evidence and perspectives

Metabolic syndrome (MetS) is defined as the co-occurrence of metabolic risk factors that includes insulin resistance, hyperinsulinemia, impaired glucose tolerance, type 2 diabetes mellitus, dyslipidemia, and visceral obesity. The clinical significance of MetS consists of identifying a subgroup of patients sharing a common physiopathological state predisposing to chronic diseases. Clinical and scientific studies pinpoint lifestyle modification as an effective strategy aiming to reduce several features accountable for the risk of MetS onset. Among the healthy dietary patterns, the Mediterranean diet (MedDiet) emerges in terms of beneficial properties associated with longevity. Current evidence highlights the protective effect exerted by MedDiet on the different components of MetS. Interestingly, the effect exerted by polyphenols contained within the representative MedDiet components (i.e., olive oil, red wine, and nuts) seems to be accountable for the beneficial properties associated to this dietary pattern. In this review, we aim to summarize the principal evidence regarding the effectiveness of MedDiet-polyphenols in preventing or delaying the physiopathological components accountable for MetS onset. These findings may provide useful insights concerning the health properties of MedDiet-polyphenols as well as the novel targets destined to a tailored approach to MetS.

Assessment of the efficacy of omega-3 fatty acids on metabolic and inflammatory parameters in patients with schizophrenia taking clozapine and sodium valproate

Omega-3 fatty acid (FA) supplementation has been reported to improve several cardio-metabolic risk factors. We aimed to assess the efficacy of omega-3 fatty acids on metabolic and inflammatory indices in patients with schizophrenia who were taking clozapine and sodium valproate. All patients were on a stable dose of 300-400mg of clozapine for 3 months. Subjects were randomized to treatment with either omega-3 fatty acid (4gr/day) or a placebo for 8 weeks. Height, weight, abdominal circumference, serum lipid profile, fasting blood glucose (FBG), and serum high sensitivity-C-reactive protein (hs-CRP) were determined at baseline and after 8 weeks of treatment. Fifty six subjects were recruited into the study. Patients with schizophrenia who were in the group receiving omega-3 FA capsules had an improvement in some anthropometric indices including weight, BMI, wrist and waist circumference, compared to the placebo group. Only changes in waist circumferences remained significantly different after adjustment for serum fasted TG. Our results showed omega-3 FA supplementation can improve some anthropometric indices in patients with schizophrenia who are taking clozapine pharmacotherapy.

Roquefort cheese proteins inhibit Chlamydia pneumoniae propagation and LPS-induced leukocyte migration

Inflammation in atherosclerosis, which could be associated with some subclinical infections such as C. pneumoniae, is one of the key factors responsible for the development of clinical complications of this disease. We report that a proprietary protein extract isolated from Roquefort cheese inhibits the propagation of C. pneumoniae in a human HL cell line in a dose-dependent manner, as revealed by the immunofluorescence analysis. These changes were accompanied by a significant reduction in the infective progeny formation over the protein extract range of 0.12–0.5 μg/mL. Moreover, short term feeding of mice with Roquefort cheese (twice, 10 mg per mouse with an interval of 24 hours) led to the inhibition of the migration of peritoneal leukocytes caused by intraperitoneal injection of E. coli lipopolysaccharide. These changes were complemented by a reduction in neutrophil count and a relative increase in peritoneal macrophages, suggesting that ingestion of Roquefort could promote regenerative processes at the site of inflammation. The ability of this protein to inhibit propagation of Chlamydia infection, as well as the anti-inflammatory and proregenerative effects of Roquefort itself, may contribute to the low prevalence of cardiovascular mortality in France where consumption of fungal fermented cheeses is the highest in the world.

The fatty acid and tocopherol constituents of the seed oil extracted from 21 grape varieties (Vitis spp.)

BACKGROUND

Fatty acids and tocopherols in appropriate quantities are invaluable attributes that are desirable in seeds of agricultural products. Studies have generally focused on the evaluation of the oil and tocopherol components of oil crops. Recently, investigations revealed that the grape seed has robust potential in the production of healthy fatty acids as well as tocopherols. This study was thus conducted to determine the oil and tocopherol components of grape seeds, obtained from various grape cultivars of different species, including two rootstock varieties.

RESULTS

The grape seed oil concentration of the studied varieties ranged from 7.3 to 22.4%. The determined fatty acid profiles of the genotypes conformed to the pattern described in the literature for grapes. Linoleic acid is the major component comprising 53.6-69.6% of the total, followed by oleic (16.2-31.2%), palmitic (6.9-12.9%) and stearic (1.44-4.69%). The oils of all the seeds analysed showed a preponderance of α-tocopherol (ranging from 260.5 to 153.1 mg kg⁻¹ oil extract). β-Tocopherol, γ-tocopherol and δ-tocopherol were also detected with the general means of 0.98, 22.2 and 0.92 mg kg⁻¹, respectively. Linoleic acid showed a significantly negative correlation with all the fatty acids analysed. The strongest negative correlation existed between linoleic and oleic acids (r = -0.834, P < 0.01).

CONCLUSION

Present investigations indicated that oil content, fatty acid composition and tocopherol constituents of grape seed show great variation among the genotypes. Markedly higher proportions of linoleic acid with considerable amounts of tocopherols found in the oil samples suggest that grape seed is a good source for culinary, pharmaceutical and cosmetic uses.

Essential fatty acid intake and coronary heart disease risk factors among college students of 3 ethnic groups

OBJECTIVES

Few studies address gender and ethnic variations in essential fatty acid (EFA) intake and risk factors for coronary heart disease (CHD). The purpose of this study was to estimate EFA intake among college students of 3 ethnic groups and compare the relationship between EFA intake and CHD risk factors.

METHODS

Using a cross-sectional design, 300 subjects from 3 ethnic groups--one-third (n = 100) non-Hispanic white, one-third Hispanic, and one-third non-Hispanic black-completed the Cardiovascular Risk Assessment Instruments and a Food Frequency Questionnaire to determine fatty acid intake. Measured CHD risk factors were quantified as CHD Risk Point Standards (CHDRPS).

RESULTS

Results showed that Hispanic females had a significantly higher mean percent intake of arachidonic acid and ratio of linoleic acid to alpha-linolenic acid than non-Hispanic white females, and Hispanic males had significantly higher mean percent intake of EPA and [EPA plus docosahexaenoic acid (DHA)] than non-Hispanic white males. An inverse correlation was found between CHDRPS and DHA among non-Hispanic blacks. A significant positive correlation was found between CHDRPS and linoleic acid among non-Hispanic white females, as well as serum homocysteine (tHcy) concentrations and the ratio of linoleic acid to alpha-linolenic acid intake among non-Hispanic black females.

CONCLUSION

Gender and ethnic differences play a role in adherence to dietary guidelines, demonstrating relevance for future research in this area.

Session 4: CVD, diabetes and cancer Evidence for the use of the Mediterranean diet in patients with CHD

Diet is associated with the development of CHD. The incidence of CHD is lower in southern European countries than in northern European countries and it has been proposed that this difference may be a result of diet. The traditional Mediterranean diet emphasises a high intake of fruits, vegetables, bread, other forms of cereals, potatoes, beans, nuts and seeds. It includes olive oil as a major fat source and dairy products, fish and poultry are consumed in low to moderate amounts. Many observational studies have shown that the Mediterranean diet is associated with reduced risk of CHD, and this result has been confirmed by meta-analysis, while a single randomised controlled trial, the Lyon Diet Heart study, has shown a reduction in CHD risk in subjects following the Mediterranean diet in the secondary prevention setting. However, it is uncertain whether the benefits of the Mediterranean diet are transferable to other non-Mediterranean populations and whether the effects of the Mediterranean diet will still be feasible in light of the changes in pharmacological therapy seen in patients with CHD since the Lyon Diet Heart study was conducted. Further randomised controlled trials are required and if the risk-reducing effect is confirmed then the best methods to effectively deliver this public health message worldwide need to be considered.

Modificaciones en el perfil lipídico tras el consumo regular de conservas de pescado. Influencia de la adición de isoflavonas, ácidos grasos omega-3 y fitoesteroles

BACKGROUND AND OBJECTIVE

Changes in dietary habits are associated with an improvement of lipid profile. We decided to assess changes in lipid profile reached with a dietary enrichment with canned tuna in olive oil and compared them with those reached with canned tuna with additional supplementation.

SUBJECTS AND METHOD

In a prospective, randomized, single blind study, 400 participants were assigned to a daily intake of canned tuna in olive oil alone (control group) or enriched with: isoflavones, omega-3 fatty acids of phytosterols, during three months. Plasmatic lipid levels were measured before and after intervention. Changes of lipid levels between basal and final visits and differences between the 4 types of supplementations were evaluated.

RESULTS

The mean age of the study population was 53 years, 45% of them being males. In all 4 groups a significant reduction of total cholesterol, low-density lipoprotein (LDL)-cholesterol levels and total cholesterol/high-density lipoprotein (HDL)-cholesterol ratio was observed after 3 months of follow-up; there were no significant changes of triglycerides nor HDL-cholesterol levels. The comparison between different types of supplementation revealed that only phytosterols addition reached a greater reduction of total cholesterol and LDL-cholesterol levels than canned tuna in olive oil alone (p < 0.05), and the differences between the remaining 2 supplementations and the control group were not significant.

CONCLUSIONS

Regular intake of enrichment with canned tuna supplementation is associated with improvement of lipid profile. The addition of isoflavones, omega-3 fatty acids or phytosterols supplementations increases fish consume effect, although only the enrichment with phytosterols reaches significantly better results.

Alpha-linolenic acid-enriched diet prevents myocardial damage and expands longevity in cardiomyopathic hamsters

Randomized clinical trials have demonstrated that the increased intake of omega-3 polyunsaturated fatty acids significantly reduces the risk of ischemic cardiovascular disease, but no investigations have been performed in hereditary cardiomyopathies with diffusely damaged myocardium. In the present study, delta-sarcoglycan-null cardiomyopathic hamsters were fed from weaning to death with an alpha-linolenic acid (ALA)-enriched versus standard diet. Results demonstrated a great accumulation of ALA and eicosapentaenoic acid and an increased eicosapentaenoic/arachidonic acid ratio in cardiomyopathic hamster hearts, correlating with the preservation of myocardial structure and function. In fact, ALA administration preserved plasmalemma and mitochondrial membrane integrity, thus maintaining proper cell/extracellular matrix contacts and signaling, as well as a normal gene expression profile (myosin heavy chain isoforms, atrial natriuretic peptide, transforming growth factor-beta1) and a limited extension of fibrotic areas within ALA-fed cardiomyopathic hearts. Consequently, hemodynamic indexes were safeguarded, and more than 60% of ALA-fed animals were still alive (mean survival time, 293+/-141.8 days) when all those fed with standard diet were deceased (mean survival time, 175.9+/-56 days). Therefore, the clinically evident beneficial effects of omega-3 polyunsaturated fatty acids are mainly related to preservation of myocardium structure and function and the attenuation of myocardial fibrosis.

Effect of omega-3 fatty acids on the lipid profile of patients taking clozapine

OBJECTIVE

This study aimed to assess the lipid-lowering properties of omega-3 fatty acids (also known as n-3 polyunsaturated fatty acids) in a group of patients taking clozapine.

METHOD

Twenty-eight persons suffering from schizophrenia or schizoaffective disorder and currently taking clozapine participated in an open-label single-arm trial. Participants received supplements of 10 g of fish oil (containing 1.8 g of eicosopentaenoic acid and 1.2 g of docosahexaenoic acid) for a period of 28 days. Plasma lipids were measured on days 0 and 28.

RESULTS

This study demonstrated high rates of lipid abnormalities in the participants. Participants taking omega-3 fatty acids demonstrated a statistically significant reduction in mean serum triglyceride levels of 22%. There was an associated increase in total cholesterol (6.6%) and low-density lipoprotein cholesterol (22%). Common side-effects included fishy burps or breath, but no serious side-effects or interactions where observed.

CONCLUSION

Omega-3 fatty acids may be of value in patients taking clozapine and who have elevated serum triglyceride levels. Limitations of the study, practical implications and directions for future research are discussed.

Schizophrenia and increased risks of cardiovascular disease

OBJECTIVE

The aim of the study is to review the absolute and relative impacts of the major causes for premature mortality among patients with schizophrenia.

DATA SOURCES

We reviewed published articles on causes of mortality in the general population as well as among patients with schizophrenia.

STUDY SELECTION

We selected articles which published total and cause-specific mortality rates.

DATA EXTRACTION

We reviewed the causes of mortality and their risk factors.

DATA SYNTHESIS

The average life expectancy of the general population is 76 years (72 years in men, 80 years in women), whereas the corresponding figure is 61 years (57 years in men, 65 years in women) among patients with schizophrenia. Thus, patients with schizophrenia have approximately a 20% reduced life expectancy compared with the general population. Although patients with schizophrenia are 10 to 20 times more likely than the general population to commit suicide, more than two thirds of patients with schizophrenia, compared with approximately one-half in the general population, die of coronary heart disease (CHD). The chief risk factors for this excess risk of death are cigarette smoking, obesity leading to dyslipidemia, insulin resistance and diabetes, and hypertension.

CONCLUSIONS

The chief cause of excess premature mortality among patients with schizophrenia is CHD, caused mainly by their adverse risk factor profile. Because patients with schizophrenia have less access to medical care, consume less medical care, and are less compliant with their regimens, the choice of antipsychotic drug regimens that do not further adversely affect their risk factor for CHD is a major clinical and public health challenge among patients with schizophrenia.

DEMONSTRATION OF DOCOSAHEXAENOIC ACID AS A BIOAVAILABILITY ENHANCER FOR CYP3A SUBSTRATES: IN VITRO AND IN VIVO EVIDENCE USING CYCLOSPORIN IN RATS

To investigate the pharmacokinetic interaction between cyclosporin A (CsA) and docosahexaenoic acid (DHA) in vivo, 5 mg/kg CsA was orally or intravenously coadministered with DHA (50-200 microg/kg) to rats. The effect of DHA on CYP3A activity was determined using rat liver microsomes in vitro. Moreover, the effect of DHA on P-glycoprotein (P-gp) function was examined using cultured Caco-2 cells in vitro. After oral coadministration of CsA with 100 microg/kg and 200 microg/kg DHA, bioavailability (BA) was significantly increased, compared with control rats. In contrast, no pharmacokinetic interaction was observed when CsA was intravenously administered in rats dosed orally with DHA, suggesting that DHA did not affect hepatic metabolism. The formation of 6beta-hydroxytestosterone from testosterone in rat liver microsomes was competitively inhibited by DHA. The Km, Vmax, and Ki values were 25.5 microM, 2.45 nmol/min/mg protein, and 5.52 microM, respectively. Moreover, basal-to-apical transport of [3H]CsA in the Caco-2 cell monolayer was not affected by DHA but was decreased by valspodar (PSC 833), a P-gp inhibitor. Our finding is the first to indicate that DHA inhibits intestinal CYP3A both in vitro and in vivo, but not P-gp. It was thus demonstrated that DHA could be used as a BA enhancer for the drugs that are extensively metabolized by CYP3A in the gut.

Government perspective: food labeling

The Food and Drug Administration acknowledges the severity of the obesity epidemic. The Food and Drug Administration recognizes the importance of food labeling as a vehicle for dietary messages and, thus, enforces stringent guidelines to maintain the integrity of the food label. As food labels await another upgrade to make them more effective and easier to understand, the Food and Drug Administration considers what information will be most useful for consumers to make healthy choices. The causal relationship between food labels and subsequent diet choice is not well understood; more research in this area is needed. The Commissioner of the Food and Drug Administration has recently appointed an Obesity Working Group to develop proposals on pertinent topics of obesity, including the role of food labeling as a dietary guide.

Identification of a long-chain polyunsaturated fatty acid acyl-coenzyme A synthetase from the diatom Thalassiosira pseudonana

The draft genome of the diatom Thalassiosira pseudonana was searched for DNA sequences showing homology with long-chain acyl-coenzyme A synthetases (LACSs), since the corresponding enzyme may play a key role in the accumulation of health-beneficial polyunsaturated fatty acids (PUFAs) in triacylglycerol. Among the candidate genes identified, an open reading frame named TplacsA was found to be full length and constitutively expressed during cell cultivation. The predicted amino acid sequence of the corresponding protein, TpLACSA, exhibited typical features of acyl-coenzyme A (acyl-CoA) synthetases involved in the activation of long-chain fatty acids. Feeding experiments carried out in yeast (Saccharomyces cerevisiae) transformed with the algal gene showed that TpLACSA was able to activate a number of PUFAs, including eicosapentaenoic acid and docosahexaenoic acid (DHA). Determination of acyl-CoA synthetase activities by direct measurement of acyl-CoAs produced in the presence of different PUFA substrates showed that TpLACSA was most active toward DHA. Heterologous expression also revealed that TplacsA transformants were able to incorporate more DHA in triacylglycerols than the control yeast.