Fish oil and cardiovascular disease: lipids and arterial function

[Fish omega-3 fatty acids and risk of coronary heart disease]

A great amount of evidence from epidemiological studies and clinical trials supports a protective effect against coronary heart disease for fish consumption and intake of marine omega-3 fatty acids. Biological pathways for this risk reduction include membrane stabilization in the cardiac myocite, inhibition of platelet aggregation, favourable modifications of the lipid profile, decrease in blood pressure and reduction of the inflammatory response of the endothelium. Results from epidemiological studies suggest a threshold effect for the consumption of fish and omega-3 fatty acids. Risk reduction is especially important for cardiac sudden death. Nevertheless, protection against non-fatal coronary heart disease has also been observed. Recently published studies have shown that mercury intake, present in high concentrations in fish, could counteract the beneficial effect from fish consumption.

Fish consumption and blood lipids in three ethnic groups of Québec (Canada)

The purpose of this study was to compare fish intake and plasma phospholipid concentrations of n-3 fatty acids, in particular of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), among representative population samples of Québecers, James Bay Cree, and Inuit of Nunavik (Canada). The relationships between these concentrations and cardiovascular disease (CVD) risk factors were also investigated and compared in the three populations. In 1990-1992, the study subjects had participated in the extensive Santé Québec health surveys conducted in southern Québec, James Bay, and Nunavik. Significant differences in levels of CVD risk factors were found among these three populations. Globally, Inuit showed the lowest risk status for CVD compared with Cree and Québecers, despite the high prevalence of cigarette smoking and obesity. Daily fish intakes varied significantly among the three groups, averaging 13, 60, and 131 g for Québecers, Cree, and Inuit, respectively. Concentrations of EPA + DHA in plasma phospholipids were highest among Inuit (8.0%), second-highest among Cree (3.9%), and lowest among Québecers (1.8%). When the three populations were grouped together, there was a positive association between concentrations of EPA + DHA stratified into quartiles and HDL cholesterol, with a significant relation in quartile 4 (EPA + DHA > or = 4.04%). An inverse relation was also found between EPA + DHA and triacylglycerols in quartile 4. Our results indicate that increased consumption of fish as a source of n-3 fatty acids is beneficially associated with levels of HDL cholesterol and triacylglycerols.

Dietary intake of fish vs. formulations leads to higher plasma concentrations of n-3 fatty acids

The n-3 fatty acids from fish appear to be more efficacious, in terms of cardioprotection, than equivalent amounts provided as capsules. Volunteers were given, for 6 wk, either 100 g/d of salmon, providing 383 mg of EPA and 544 mg of DHA, esterified in glycerol lipids, or 1 or 3 capsules of fish oil/d, providing 150 mg of EPA and 106 mg of DHA or 450 mg of EPA and 318 mg of DHA, as ethyl esters. Further, we reevaluated data from a previous study carried out with the same design, i.e., with 3 and 6 capsules/d of fish oil, providing 1290 and 2580 mg/d EPA and 960 and 1920 mg/d DHA. Marked increments in plasma EPA and DHA concentrations (microg/mg total lipid) and percentages of total fatty acids were recorded at the end of treatment with either n-3 capsules or salmon. Net increments of EPA and DHA in plasma lipids were linearly and significantly correlated with the dose after capsule administration. Further, increments in plasma EPA and DHA concentration after salmon intake were significantly higher than after administration of capsules. The same increments would be obtained with at least two- and ninefold higher doses of EPA and DHA, respectively, if administered with capsules rather than salmon. We provide experimental evidence that n-3 fatty acids from fish are more effectively incorporated into plasma lipids than when administered as capsules and that increments in plasma concentrations of EPA and DHA given as capsules are linearly correlated with their intakes.

Fat, fishing patterns, and health among the Bardi people of north Western Australia

Research into the resource use strategies of the Bardi Aboriginal People of One Arm Point, Western Australia, found that they maximize the consumption of specific beneficial marine FA. The Bardi assess the relative fatness of fish and animal species in their environment, procuring fish and marine species only when they are considered to be at their fattest stage: during specific seasons; at specific physiological life stages, or through on-site evaluation. In June 1999 and September 2000, samples of fish, dugong, oyster, and turtle were collected by Bardi fishermen, focusing specifically on species considered to be high in fat content and very popular among the Bardi. Nine species were analyzed for total lipids and FA profile, which were determined by capillary GLC. Comparative lipid analysis established that the Bardi hunters' selection process between species and within species and the selection of specific fish fat deposits increase the levels of beneficial F made available to the community. Bardi fishing and hunting patterns meet a demand for fat within the community and may protect many species of fish whose spawning season is inversely related to the accumulation of the specific gut fat deposits sought by the Bardi. These fat deposits make up for the relatively low levels of fat in the flesh of tropical fish. The Bardi model provides important insights into the nature of human-environment interaction and expands our understanding of the role that warmer-water fisheries can play in human health.

Cardiac benefits of fish consumption may depend on the type of fish meal consumed: the Cardiovascular Health Study

BACKGROUND

Few studies have examined associations of fish consumption with ischemic heart disease (IHD) risk among older adults or how different types of fish meals relate to IHD risk.

METHODS AND RESULTS

In a population-based prospective cohort study, usual fish consumption was ascertained at baseline among 3910 adults aged > or =65 years and free of known cardiovascular disease in 1989 and 1990. Consumption of tuna and other broiled or baked fish correlated with plasma phospholipid long-chain n-3 fatty acids, whereas consumption of fried fish or fish sandwiches (fish burgers) did not. Over 9.3 years' mean follow-up, there were 247 IHD deaths (including 148 arrhythmic deaths) and 363 incident nonfatal myocardial infarctions (MIs). After adjustment for potential confounders, consumption of tuna or other broiled or baked fish was associated with lower risk of total IHD death (P for trend=0.001) and arrhythmic IHD death (P=0.001) but not nonfatal MI (P=0.44), with 49% lower risk of total IHD death and 58% lower risk of arrhythmic IHD death among persons consuming tuna/other fish 3 or more times per week compared with less than once per month. In similar analyses, fried fish/fish sandwich consumption was not associated with lower risk of total IHD death, arrhythmic IHD death, or nonfatal MI but rather with trends toward higher risk.

CONCLUSIONS

Among adults aged > or =65 years, modest consumption of tuna or other broiled or baked fish, but not fried fish or fish sandwiches, is associated with lower risk of IHD death, especially arrhythmic IHD death. Cardiac benefits of fish consumption may vary depending on the type of fish meal consumed.

Kinetic studies of lipoprotein metabolism in the metabolic syndrome including effects of nutritional interventions

Nutritional interventions may favourably regulate dyslipoproteinemia and, hence, decrease cardiovascular disease risk. Lipoprotein kinetic studies afford a powerful approach to understanding and defining the mechanisms by which such interventions modulate lipoprotein metabolism. Stable isotope tracers and compartment models are now commonly employed for such studies. We review the recent application of tracer methodologies to the study of dyslipoproteinemia in the metabolic syndrome. We also focus on the effects of nutritional intervention studies that have addressed the effects of weight loss, n-3 fatty acids, plant sterols and alcohol on very low density lipoprotein, LDL and HDL metabolism. The potential for statin treatment as an adjunct to dietary modification is also discussed. New tracer methodologies are discussed, specifically those referring to reverse cholesterol transport. The nutritional interventions discussed in this review are readily transferable into clinical preventive practice. The potential benefits to be gained by weight loss and fish oil supplementation in the metabolic syndrome extend beyond their specific and positive effects on lipoprotein metabolism. Furthermore, recent developments in tracer methodologies afford new tools for probing the in-vivo pathways of lipoprotein metabolism in future studies.

Effects of supplementation with fish oil-derived n-3 fatty acids and gamma-linolenic acid on circulating plasma lipids and fatty acid profiles in women

BACKGROUND

Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and gamma-linolenic acid (GLA) have lipid-modifying and antiinflammatory properties. The effects of supplement mixtures of these fatty acids on plasma lipids and the fatty acid compositions of serum phospholipids have received little attention.

OBJECTIVE

The objective was to determine the effects of different levels of GLA supplementation together with a constant intake of EPA plus DHA on the triacylglycerol-lowering effect of EPA plus DHA alone and on the fatty acid patterns (eicosanoid precursors) of serum phospholipids.

DESIGN

Thirty-one women were assigned to 1 of 4 groups, equalized on the basis of their fasting triacylglycerol concentrations. They received supplements providing 4 g EPA+DHA (4:0, EPA+DHA:GLA; control group), 4 g EPA+DHA plus 1 g GLA (4:1), 2 g GLA (4:2), or 4 g GLA (4:4) daily for 28 d. Plasma lipids and fatty acids of serum phospholipids were measured on days 0 and 28.

RESULTS

Plasma triacylglycerol concentrations were significantly lower on day 28 than on day 0 in the 4:0, 4:1, and 4:2 groups. LDL cholesterol decreased significantly (by 11.3%) in the 4:2 group. Dihomo-gamma-linolenic acid increased significantly in serum phospholipids only in the 4:2 and 4:4 groups; however, total n-3 fatty acids increased in all 4 groups.

CONCLUSIONS

A mixture of 4 g EPA+DHA and 2 g GLA favorably altered blood lipid and fatty acid profiles in healthy women. On the basis of calculated PROCAM values, the 4:2 group was estimated to have a 43% reduction in the 10-y risk of myocardial infarction.

Effect of fish oil on LDL oxidation and plasma homocysteine concentrations in health

Oxidation of low-density lipoprotein (LDL) and hyperhomocysteinemia are believed to play a role in therogenesis. Whether n-3 polyunsaturated fatty acids increase LDL susceptibility to oxidation or influence homocysteine (Hcy) metabolism has long been a subject of controversy. In this study, we evaluated the effect of 8 weeks of dietary supplementation with 6 g/day of fish oil (FO; 3 g of n-3 fatty acids) on plasma lipoproteins, in vitro LDL peroxidation, antioxidant status, and plasma Hcy concentrations in 16 normolipidemic subjects. FO rapidly and significantly (P < .01) decreased plasma total and very low density lipoprotein triglyceride concentrations and had no effect on LDL or high-density-lipoprotein cholesterol. The mean lag time before onset of Cu(2+)-induced LDL oxidation, as well as plasma and LDL alpha-tocopherol and beta-carotene concentrations, was unchanged. However, changes in plasma aminothiol concentrations occurred during the study. Specifically, a progressive and significant increase in total Hcy plasma concentrations was observed (13.4% and 20% after 4 and 8 weeks, respectively; P < .01). Total glutathione concentrations were significantly higher after 8 weeks (P < .05). The tHcy increase was not associated with changes in plasma folate or vitamin B(12) concentrations. However, concentrations of plasma nitric oxide metabolites (NO(x) = NO(2) + NO(3)) were significantly higher than at baseline after 8 weeks of FO intake (74%; P < .01). Further, the changes in total Hcy and NO(x) plasma concentrations observed after 8 weeks of FO were found to be significantly correlated (r = .78, P < .001). With this study, we report for the first time the apparent interaction of n-3 fatty acids and nitric oxide on Hcy metabolism.

Variability of fish consumption within the 10 European countries participating in the European Investigation into Cancer and Nutrition (EPIC) study

OBJECTIVE

To describe and compare the consumption of total fish (marine foods) and the fish sub-groups - white fish, fatty fish, very fatty fish, fish products and crustacea, in participants from the European Investigation into Cancer and Nutrition (EPIC) study.

DESIGN

Cross-sectional analysis of dietary intake using a computerised standardised 24-hour recall interview. Crude means, means and standard errors adjusted by age, season and day of the week were calculated, stratified by centre and gender.

SETTING

Twenty-seven redefined centres in the 10 European countries participating in the EPIC study.

SUBJECTS

In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, selected from the main EPIC cohort.

RESULTS

A six- to sevenfold variation in total fish consumption exists in women and men, between the lowest consumption in Germany and the highest in Spain. Overall, white fish represented 49% and 45% of the intake of total fish in women and men, respectively, with the greatest consumption in centres in Spain and Greece and the least in the German and Dutch centres. Consumption of fatty fish reflected that of total fish. However, the greatest intake of very fatty fish was in the coastal areas of northern Europe (Denmark, Sweden and Norway) and in Germany. Consumption of fish products was greater in northern than in southern Europe, with white fish products predominating in centres in France, Italy, Spain, The Netherlands and Norway. Intake of roe and roe products was low. The highest consumption of crustacea was found in the French, Spanish and Italian centres. The number of fish types consumed was greater in southern than in northern Europe. The greatest variability in consumption by day of the week was found in the countries with the lowest fish intake.

CONCLUSIONS

Throughout Europe, substantial geographic variation exists in total fish intake, fish sub-groups and the number of types consumed. Day-to-day variability in consumption is also high.

The n-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid increase systemic arterial compliance in humans

BACKGROUND

n-3 Fatty acids influence vascular function, but the effect of individual fatty acids on systemic arterial compliance (SAC) has not been reported. SAC, which reflects arterial elasticity, is emerging as a new cardiovascular risk factor and appears to predict future cardiovascular events.

OBJECTIVE

We tested whether the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) improve SAC in dyslipidemic subjects.

DESIGN

Thirty-eight dyslipidemic subjects were randomly assigned to receive 3 g EPA/d (n = 12), 3 g DHA/d (n = 12), or a placebo (n = 14) in a 7-wk parallel, double-blind trial. Arterial functions were measured at the beginning and end of the interventions. Plasma lipids and plasma fatty acids were also measured.

RESULTS

Consumption of the n-3 fatty acids significantly increased SAC, whereas consumption of the placebo did not (P = 0.043; repeated-measures analysis of variance across the 3 groups); the increase was 36% with EPA and 27% with DHA. The major components contributing to the increase in SAC (systolic and pulse pressures and total vascular resistance) tended to decrease but not significantly. Plasma total and VLDL triacylglycerol were significantly lower in the n-3 fatty acid groups (P = 0.026 and 0.006, respectively; repeated-measures analysis of variance) than in the placebo group.

CONCLUSION

EPA and DHA increase SAC and tend to reduce pulse pressure and total vascular resistance, effects that may reduce the risk of adverse cardiovascular events.

Glu298Asp endothelial nitric oxide synthase gene polymorphism interacts with environmental and dietary factors to influence endothelial function

An endothelial nitric oxide synthase (eNOS) gene polymorphism (Glu298Asp) has been associated with cardiovascular disease. We investigated whether carriage of the polymorphism was associated with functional changes in the endothelium, and how genotype altered the harmful and beneficial impact of environmental influences on the endothelium. Endothelium-dependent, flow-mediated brachial artery dilatation (FMD) and endothelium-independent dilatation response to glyceryl trinitrate were measured using high-resolution ultrasound in 248 subjects (131 female, 117 male, aged 20 to 28) genotyped for the Glu298Asp polymorphism. Vascular function was compared between genotype groups and interactions with the proatherogenic risk factor, smoking, and the antiatherogenic influence of n-3 fatty acids (n-3FA) were investigated. Vascular function was not related to genotype in the group as a whole or within sexes. However, among males, smoking was associated with lower FMD in Asp298 carriers (nonsmokers 0.125+/-0.085 mm versus smokers 0.070+/-0.060 mm, P=0.006) but not in Glu298 homozygotes (nonsmokers 0.103+/-0.090 mm versus smokers 0.124+/-0.106, P=0.5). In the whole group, n-3FA levels were positively related to FMD in Asp298 carriers (reg coeff=0.023 mm/%, P=0.04, r=0.20) but not in Glu298 homozygotes (reg coeff=-0.019 mm/%, P=0.1). These differences between genotype groups were significant in interaction models. The Glu298Asp polymorphism is associated with differences in endothelial responses to both smoking and n-3 FA in healthy young subjects. These findings raise the possibility of genotype-specific prevention strategies in cardiovascular disease.

Lipid, FA, and sterol composition of New Zealand green lipped mussel (Perna canaliculus) and Tasmanian blue mussel (Mytilus edulis)

The lipid, FA, and sterol composition of the New Zealand green lipped mussel (NZGLM, Perna canaliculus) and of the Tasmanian blue mussel (TBM, Mytilus edulis) were compared using TLC-FID and GC-MS. The respective mussel species were obtained from three different sites in both New Zealand (NZ) and Tasmania. Lipid class distribution of both mussel species was characterized by a high proportion of phospholipid (PL, 57-79%) and TG (10-25%), FFA (7-12%), and sterols (ST, 12-18%). The NZGLM had higher proportions of TG, FFA, and ST (P < 0.01), whereas the TBM had a higher proportion of PL (P < 0.01). There were higher proportions of total PUFA, saturated FA, n-3 FA, and hydroxy and nonmethylene-interrupted FA (P < 0.05) in the TBM compared with the NZGLM. The major FA in the NZGLM were 16:0 (15-17%), 20:5n-3 (14-20%), and 22:6n-3 (11-17%). The same FA dominated lipids in the TBM, although there were significantly higher proportions of 16:0 (P = 0.000) and 22:6 n-3 (P = 0.003) and lower proportions of 20:5n-3 (P = 0.0072) in the TBM. A novel PUFA, 28:8n-3, was detected in both mussels with higher amounts in the TBM, which probably reflects a greater dietary contribution of dinoflagellates for this species. Cholesterol was the dominant sterol in both mussels. Other major sterols included brassicasterol, 22-methylcholesterol, trans-22-dehydrocholesterol, and desmosterol. There were significant differences (P < 0.05) between the NZGLM and TBM for 12 of the 20 sterols measured. Six sterols showed significant site differences for the NZGLM, and 10 for the TBM. The differences in the FA and sterol composition between the two species may be due to the diet of the NZGLM being more diatom-derived and the diet of the TBM having a greater dinoflagellate component.

Herbal and nonherbal supplements in medical-psychiatric patient populations

Nutritional supplements remain a popular choice for patients seeking relief or prevention from a wide range of physical and mental disorders. Review of available literature finds support for some therapeutic uses, but flaws in study design (e.g., small sample sizes) and methodology (e.g., inadequate blinding and a lack of placebo control) limit the possibility of making strong recommendations. Quality-control issues also raise concerns about the safety of supplement use (see previous list). In addition, potential interactions with prescription drugs are another consideration (Table 1). By becoming more knowledgeable about the risks and benefits of nutritional supplements, psychiatrists can assist patients in making informed choices and avoiding unnecessary harm.

Effects of oleic-rich and omega-3-rich diets on serum lipid pattern and lipid oxidation in mildly hypercholesterolemic patients

AIMS

To evaluate which dietary fat elicits the best response in terms of plasma lipids, lipoproteins, and oxidative processes.

METHODS

After a 4-week run-in period, 14 mildly hypercholesterolemic subjects were fed two balanced diets for 6-week periods. During the first intervention period, patients received a monounsaturated fatty acid (MUFA)-enriched diet (olive oil diet). During the second period this diet was supplemented by n-3 polyunsaturated fatty acids (PUFAs) (n-3 diet).

RESULTS

After the olive oil diet, a significant decrease in total serum cholesterol (-8.54%, P<0.01), and in apolipoprotein B (Apo B) (-10.0%, P<0.01) was observed. With the addition of n-3 fatty acids no further significant changes in serum lipid concentrations were found. However, the n-3 diet was followed by an increase in lipoperoxides in isolated native low-density lipoprotein (LDL) (67.23%, P<0.01).

CONCLUSIONS

A beneficial effect on the serum lipid pattern was observed with the olive oil-enriched diet. The lack of further beneficial modifications on blood lipids and lipoproteins and the increase in the oxidative susceptibility of LDL observed after the addition of n-3 PUFA to the olive oil diet does not favor the use of this diet in hypercholesterolemic patients if it is not associated with a high intake of antioxidants.

Incorporation of alpha-tocopherol in marine lipid-based liposomes: in vitro and in vivo studies

Liposomes made from a natural marine lipid extract and containing a high polyunsaturated n-3 fatty lipid ratio were envisaged as oral route vectors and a potential alpha-tocopherol supplement. The behavior of vesicles obtained by simple filtration and of giant vesicles prepared by electroformation was investigated in gastrointestinal-like conditions. The influence of alpha-tocopherol incorporation into liposomes was studied on both physical and chemical membrane stability. Propanal, as an oxidation product of n-3 polyunsaturated fatty acids, was quantified by static headspace gas chromatography when alpha-tocopherol incorporation into liposome ratios ranged from 0.01 to 12 mol%. Best oxidative stability was obtained for liposomes that contained 5 mol% alpha-tocopherol. Compared to the other formulas, propanal formation was reduced, and time of the oxidation induction phase was longer. Moreover, alpha-tocopherol induced both liposome structural modifications, evidenced by turbidity, and phospholipid chemical hydrolysis, quantified as the amount of lysophospholipids. This physicochemical liposome instability was even more pronounced in acid storage conditions, i.e., alpha-tocopherol incorporation into liposome membranes accelerated the structural rearrangements and increased the rate of phospholipid hydrolysis. In particular, giant vesicles incubated at pH 1.5 underwent complex irreversible shape transformations including invaginations. In parallel, the absorption rate of alpha-tocopherol was measured in lymph-cannulated rats when alpha-tocopherol was administrated, as liposome suspension or added to sardine oil, through a gastrostomy tube. Alpha-tocopherol recovery in lymph was increased by almost threefold, following liposome administration. This may be related to phospholipids that should favor alpha-tocopherol solubilization and to liposome instability in the case of a high amount of alpha-tocopherol in the membranes. A need to correlate results obtained from in vitro liposome behavior with in vivo lipid absorption was demonstrated by this study.

n-3 Polyunsaturated fatty acids, fish, and nonfatal acute myocardial infarction

BACKGROUND

The relation between n-3 polyunsaturated fatty acids (PUFAs), fish intake, and risk of coronary heart disease is controversial.

METHODS AND RESULTS

An Italian case-control study including 507 patients with nonfatal acute myocardial infarction (AMI) and 478 hospital controls found a multivariate odds ratio (OR) of 0.67 (95% CI, 0.47 to 0.95) for the highest n-3 PUFA intake and 0.68 (95% CI, 0.47 to 0.98) for an intake of >1 portion of fish per week compared with >/=2 portions per week.

CONCLUSIONS

Small amounts of n-3 PUFAs may be inversely related to AMI risk in this low-risk population.

Site-specific differences in the fatty acid composition of abdominal adipose tissue in an obese population from a Mediterranean area: relation with dietary fatty acids, plasma lipid profile, serum insulin, and central obesity

BACKGROUND

Abdominal obesity is associated with coronary risk, although causality is not well established.

OBJECTIVE

In an obese Mediterranean population, we measured the fatty acid composition of adipose tissue, its relation with dietary fatty acids and central fat deposition, and its influence on plasma lipids and insulin.

DESIGN

Adipose tissue samples were obtained from 84 obese patients (29 men, 55 women) aged 30-70 y (body mass index, in kg/m(2): 27-35). We measured concentrations of insulin and lipids in plasma and fatty acids in subcutaneous, omental, and perivisceral fat. Dietary fatty acid intake was assessed with a 7-d diet record.

RESULTS

The population studied was normolipidemic and normoinsulinemic. There were important differences in fatty acid composition between tissue sites: saturated fatty acids were higher and monounsaturated fatty acids were lower in perivisceral than in subcutaneous fat (P < 0.05). Significant correlations were found for oleic, linoleic, alpha-linolenic, and total n-6 polyunsaturated fatty acids between the subject's habitual diet and adipose tissue composition. Oleic and n-3 fatty acids from adipose regions were negatively correlated with apolipoprotein B and triacylglycerols; adipose tissue 22:1n-9, 20:2n-6, stearic acid, and eicosapentaenoic acid were positively correlated with HDL and apolipoprotein A; and adipose tissue myristic acid was negatively correlated with apolipoprotein A (P < 0.05). Central obesity was positively associated with n-6 polyunsaturated fatty acids and inversely associated with monounsaturated fatty acids and n-3 polyunsaturated fatty acids in adipose tissue (P < 0.05).

CONCLUSION

The differences found in the composition and metabolism of perivisceral, omental, and subcutaneous fats may indicate that their atherogenic capacities also differ.

Relations between n-3 fatty acid status and cardiovascular disease risk factors among Quebecers

BACKGROUND

Epidemiologic evidence shows an inverse relation between fish consumption and death from ischemic heart disease. This beneficial effect is attributed to n-3 fatty acids.

OBJECTIVES

The purpose of this study was to examine the association between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among Quebecers.

DESIGN

The study population consisted of 1460 subjects aged 18-74 y who participated in the 1990 Quebec Heart Health and Nutrition Survey. Data were obtained through home interviews and clinic visits.

RESULTS

Expressed as the percentage of total fatty acids in plasma phospholipids, the geometric means of EPA, DHA, and their combination were 0.47%, 1.19%, and 1.70%, respectively. Concentrations of n-3 fatty acids were positively associated with fish intake. We found positive associations between EPA and total cholesterol, LDL cholesterol, HDL cholesterol, plasma glucose, and systolic and diastolic blood pressure. We found positive associations between DHA and total cholesterol, the ratio of total to HDL cholesterol, triacylglycerols, systolic blood pressure, and plasma glucose and insulin. We also found positive associations between the ratio of EPA to arachidonic acid and total cholesterol, HDL cholesterol, and systolic blood pressure and a negative association with the ratio of total to HDL cholesterol.

CONCLUSIONS

Our results indicate that concentrations of EPA and DHA in plasma phospholipids reflected Quebecer fish consumption. Results also show that EPA and the ratio of EPA to arachidonic acid can positively influence HDL-cholesterol concentrations.

Life span is prolonged in food-restricted autoimmune-prone (NZB x NZW)F(1) mice fed a diet enriched with (n-3) fatty acids

Moderate food and/or energy (calorie) restriction delays age-related immune dysfunction and prolongs life span in multiple animal models. The amount and type of dietary fatty acids can also profoundly affect life span. Marine-derived fish oils contain (n-3) fatty acids, which have potent anti-inflammatory properties. We therefore examined the influence of food restriction (40% overall reduction in intake of all dietary components) combined with substitution of fish oil for corn oil in a factorial design. Autoimmune-prone (NZB x NZW)F(1) (B/W) mice, which develop fatal autoimmune renal disease, were used. The food-restricted/fish oil diet maximally extended median life span to 645 d (vs. 494 d for the food-restricted corn oil diet). Similarly, fish oil prolonged life span in the ad libitum-fed mice to 345 d (vs. 242 for the ad libitum/corn oil diet). Increased life span was partially associated with decreased body weight, blunting renal proinflammatory cytokine (interferon-gamma, interleukins-10 and -12 and tumor necrosis factor-alpha) levels and lower nuclear factor-kappaB (NF-kappaB). Reductions in NF-kappaB were preceded by enhanced superoxide dismutase, catalase and glutathione peroxidase activities. These findings demonstrate the profound additive effects of food restriction and (n-3) fatty acids in prolonging life span in B/W mice. These observations may have additional implications in the management of obesity, diabetes, cancer and/or the aging process.

n-3 Fatty acids and cardiovascular disease risk factors among the Inuit of Nunavik

BACKGROUND

Inuit traditionally consume large amounts of marine foods rich in n-3 fatty acids. Evidence exists that n-3 fatty acids have beneficial effects on key risk factors for cardiovascular disease.

OBJECTIVE

Our goal was to verify the relation between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among the Inuit of Nunavik, Canada.

DESIGN

The study population consisted of 426 Inuit aged 18-74 y who participated in a 1992 health survey. Data were obtained through home interviews and clinical visits. Plasma samples were analyzed for phospholipid fatty acid composition.

RESULTS

Expressed as the percentage of total fatty acids, geometric mean concentrations of EPA, DHA, and their combination in plasma phospholipids were 1.99%, 4.52%, and 6.83%, respectively. n-3 Fatty acids were positively associated with HDL-cholesterol concentrations and inversely associated with triacylglycerol concentrations and the ratio of total to HDL cholesterol. In contrast, concentrations of total cholesterol, LDL cholesterol, and plasma glucose increased as n-3 fatty acid concentrations increased. There were no significant associations between n-3 fatty acids and diastolic and systolic blood pressure and plasma insulin.

CONCLUSIONS

Consumption of marine products, the main source of EPA and DHA, appears to beneficially affect some cardiovascular disease risk factors. The traditional Inuit diet, which is rich in n-3 fatty acids, is probably responsible for the low mortality rate from ischemic heart disease in this population.

Non-herbal nutritional supplements-the next wave: a comprehensive review of risks and benefits for the C-L psychiatrist

The continuing popularity of complementary medicine has led to the frequent appearance of new products in the marketplace. Non-herbal supplements are now a popular choice for patients seeking relief from a variety of medical conditions. As with herbal medicines, there are concerns about the safety of these products in those with physical illness. Clearly, consultation-liaison psychiatrists will encounter patients using non-herbal products or inquiring about them. This article seeks to provide knowledge about the risks and benefits of non-herbal supplements that consultation-liaison psychiatrists are likely to encounter.

Effects of fish oils and fish on cardiovascular disease

The effects of fish oils, fish, and omega-3 (n-3) fatty acids on cardiovascular functions and outcomes in recently published studies are reviewed. The original hypothesis that eating fish is protective has been largely sustained but refined to indicate benefit mainly in those who are at increased risk. Biologic plausibility has been extended from the established benefit of lipid-lowering to improvements in vascular and arterial functions. A major intervention trial in patients with cardiovascular disease has confirmed the benefits of moderate amounts of long-chain n-3 fatty acids. Thus, the triad of evidence comprising epidemiology, biologic plausibility, and interventional success through a randomized, controlled trial has been established.

Hypertriglyceridemia: associated risks and effect of drug treatment

Accumulating evidence indicates that hypertriglyceridemia (HTG) is a risk factor for cardiovascular disease. This increased risk is probably substantially mediated through the metabolic interrelationships between serum triglyceride (TG) levels and other risk factors, such as the atherogenic lipid profile (low high density lipoprotein-cholesterol levels and elevated small dense low density lipoprotein levels), insulin resistance, a prothrombotic propensity and low grade systemic inflammation. TG-lowering strategy in patients with HTG encompasses dietary modification and pharmacological agents, such as fibric acid derivatives, fish-oil and hydroxymethylglutaryl coenzyme A reductase inhibitors, which have, besides their known effects on the atherogenic lipid profile, beneficial effects on other determinants of cardiovascular disease. However, in spite of data from trials investigating fibric acid derivative-induced reduction in coronary events in patients with distinct types of hyperlipidemia, no specific trials have been performed that investigated this risk reduction in patients with HTG, in whom other cardiovascular risk factors are clustered as well. Small-scale studies on determinants of cardiovascular disease in patients with HTG and post-hoc analyses of the Helsinki Heart, Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial and Bezafibrate Infarction Prevention trials in patients with high serum TG levels suggest a drug-induced reduction in cardiovascular events. However, a specific trial should be conducted to investigate the effects of lipid-lowering therapy on clinical end-points in patients with HTG of defined types.

In vitro behavior of marine lipid-based liposomes. Influence of pH, temperature, bile salts, and phospholipase A2

To deliver polyunsaturated fatty acids (PUFA) by the oral route, liposomes based on a natural mixture of marine lipids were prepared by filtration and characterized in media that mimic gastrointestinal fluids. First the influence of large pH variations from 1.5-2.5 (stomach) to 7.4 (intestine) at the physiological temperature (37 degrees C) was investigated. Acidification of liposome suspensions induced instantaneous vesicle aggregation, which was partially reversible when the external medium was further neutralized. Simultaneously, complex morphological bilayer rearrangements occurred, leading to the formation of small aggregates. These pH- and temperature-dependent structural changes were interpreted in terms of osmotic shock and lipid chemical alterations, i.e., oxidation and hydrolysis, especially in the first hours of storage. Besides, oxidative stability was closely related to the state of liposome aggregation and the supramolecular organization (vesicles or mixed micelles). The effects of bile salts and phospholipase A2 (PLA2) on the liposome structures were also studied. Membrane solubilization by bile salts was favored by preliminary liposome incubation in acid conditions. PLA2 showed a better activity on liposome structures than on the corresponding mixed lipid-bile salt micelles. As a whole, in spite of slight morphological modifications, vesicle structures were preserved after an acid stress and no lipid oxidation products were detected during the first 5 h of incubation. Thus, marine lipids constituted an attractive material for the development of liposomes as potential oral PUFA supplements.

Functional foods and cardiovascular disease

Functional foods are foods that, by virtue of physiologically active food components, provide health benefits beyond basic nutrition. Many functional foods have been found to be potentially beneficial in the prevention and treatment of cardiovascular disease, the leading cause of mortality in the United States. These foods include soybeans, oats, psyllium, flaxseed, garlic, tea, fish, grapes, nuts, and stanol- and sterol ester enhanced margarine. When eaten in adequate amounts on a consistent basis, these foods may aid in decreasing the risk of cardiovascular disease by several potential mechanisms: lowering blood lipid levels, improving arterial compliance, reducing low-density lipoprotein oxidation, decreasing plaque formation, scavenging free radicals, and inhibiting platelet aggregation.