Fatty fish in the diet of patients with type 2 diabetes: comparison of the metabolic effects of foods rich in n-3 and n-6 fatty acids

Fish intake and risk of cardiovascular events: an analysis of the VITAL cohort

BACKGROUND

Dietary habits with fish consumption have been associated with a lower risk of cardiovascular (CV) disease, based on heterogenous observational studies. Current recommendations suggest eating at least 1-2 fish servings per week for CV prevention.

METHODS

We conducted a retrospective evaluation of a cohort study that enrolled a large primary prevention population to determine the potential benefit of fish intake ≥1.5 serving per week, through a multivariate Cox regression model. The outcomes of interest included all-cause mortality, cardiovascular mortality, MACE (composite endpoint of myocardial infarction, stroke, and death from cardiovascular causes), expanded MACE (MACE plus coronary revascularization), total myocardial infarction (MI), total coronary heart disease (CHD) and total stoke. The estimates were reported using hazard ratio (HR) with 99% confidence intervals (99% CI).

RESULTS

A total of 25,435 patients were evaluated (11,921 individuals ≥1.5 fish servings/week; 13,514 < 1.5 fish servings per week). Intake ≥1.5 servings/week was not independently associated with CV outcomes reduction, such as CV mortality, MI risk MACE, expanded MACE outcomes, CHD or stroke (HR 0.78, 99% CI 0.57-1.07).

CONCLUSION

Fish intake ≥1.5 servings/week was not associated with CV outcomes improvement in this analysis, but potential benefit cannot be ruled out.

Associations of Fish Consumption With Risk of Cardiovascular Disease and Mortality Among Individuals With or Without Vascular Disease From 58 Countries

IMPORTANCE

Cohort studies report inconsistent associations between fish consumption, a major source of long-chain ω-3 fatty acids, and risk of cardiovascular disease (CVD) and mortality. Whether the associations vary between those with and those without vascular disease is unknown.

OBJECTIVE

To examine whether the associations of fish consumption with risk of CVD or of mortality differ between individuals with and individuals without vascular disease.

DESIGN, SETTING, AND PARTICIPANTS

This pooled analysis of individual participant data involved 191 558 individuals from 4 cohort studies-147 645 individuals (139 827 without CVD and 7818 with CVD) from 21 countries in the Prospective Urban Rural Epidemiology (PURE) study and 43 413 patients with vascular disease in 3 prospective studies from 40 countries. Adjusted hazard ratios (HRs) were calculated by multilevel Cox regression separately within each study and then pooled using random-effects meta-analysis. This analysis was conducted from January to June 2020.

EXPOSURES

Fish consumption was recorded using validated food frequency questionnaires. In 1 of the cohorts with vascular disease, a separate qualitative food frequency questionnaire was used to assess intake of individual types of fish.

MAIN OUTCOMES AND MEASURES

Mortality and major CVD events (including myocardial infarction, stroke, congestive heart failure, or sudden death).

RESULTS

Overall, 191 558 participants with a mean (SD) age of 54.1 (8.0) years (91 666 [47.9%] male) were included in the present analysis. During 9.1 years of follow-up in PURE, compared with little or no fish intake (≤50 g/mo), an intake of 350 g/wk or more was not associated with risk of major CVD (HR, 0.95; 95% CI, 0.86-1.04) or total mortality (HR, 0.96; 0.88-1.05). By contrast, in the 3 cohorts of patients with vascular disease, the HR for risk of major CVD (HR, 0.84; 95% CI, 0.73-0.96) and total mortality (HR, 0.82; 95% CI, 0.74-0.91) was lowest with intakes of at least 175 g/wk (or approximately 2 servings/wk) compared with 50 g/mo or lower, with no further apparent decrease in HR with consumption of 350 g/wk or higher. Fish with higher amounts of ω-3 fatty acids were strongly associated with a lower risk of CVD (HR, 0.94; 95% CI, 0.92-0.97 per 5-g increment of intake), whereas other fish were neutral (collected in 1 cohort of patients with vascular disease). The association between fish intake and each outcome varied by CVD status, with a lower risk found among patients with vascular disease but not in general populations (for major CVD, I2 = 82.6 [P = .02]; for death, I2 = 90.8 [P = .001]).

CONCLUSIONS AND RELEVANCE

Findings of this pooled analysis of 4 cohort studies indicated that a minimal fish intake of 175 g (approximately 2 servings) weekly is associated with lower risk of major CVD and mortality among patients with prior CVD but not in general populations. The consumption of fish (especially oily fish) should be evaluated in randomized trials of clinical outcomes among people with vascular disease.

Seafood intake and the development of obesity, insulin resistance and type 2 diabetes

We provide an overview of studies on seafood intake in relation to obesity, insulin resistance and type 2 diabetes. Overweight and obesity development is for most individuals the result of years of positive energy balance. Evidence from intervention trials and animal studies suggests that frequent intake of lean seafood, as compared with intake of terrestrial meats, reduces energy intake by 4–9 %, sufficient to prevent a positive energy balance and obesity. At equal energy intake, lean seafood reduces fasting and postprandial risk markers of insulin resistance, and improves insulin sensitivity in insulin-resistant adults. Energy restriction combined with intake of lean and fatty seafood seems to increase weight loss. Marine n-3 PUFA are probably of importance through n-3 PUFA-derived lipid mediators such as endocannabinoids and oxylipins, but other constituents of seafood such as the fish protein per se, trace elements or vitamins also seem to play a largely neglected role. A high intake of fatty seafood increases circulating levels of the insulin-sensitising hormone adiponectin. As compared with a high meat intake, high intake of seafood has been reported to reduce plasma levels of the hepatic acute-phase protein C-reactive protein level in some, but not all studies. More studies are needed to confirm the dietary effects on energy intake, obesity and insulin resistance. Future studies should be designed to elucidate the potential contribution of trace elements, vitamins and undesirables present in seafood, and we argue that stratification into responders and non-responders in randomised controlled trials may improve the understanding of health effects from intake of seafood.

Effect of combined use of a low-carbohydrate, high-protein diet with omega-3 polyunsaturated fatty acid supplementation on glycemic control in newly diagnosed type 2 diabetes: a randomized, double-blind, parallel-controlled trial

Background

The combined effect of a low-carbohydrate, high-protein (LCHP) diet and omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on patients with type 2 diabetes (T2D) is not known.

Objective

The aim of this study was to evaluate the effect of an LCHP diet combined with ω-3 (LCHP+ω-3) on glycemic control in patients with T2D.

Design

In this randomized, double-blind, parallel-controlled trial, 122 newly diagnosed participants with T2D were randomly assigned to receive a high-carbohydrate, low-protein diet with low ω-3 PUFAs [control (CON)], an LCHP, ω-3, or LCHP+ω-3 diet for 12 wk. The ratio of carbohydrate to protein was 42:28 in the LCHP and LCHP+ω-3 diet and 54:17 in the CON and ω-3 diet. The participants were given 6 g fish oil/d (containing 3.65 g docosahexaenoic acid, eicosapentaenoic acid, and docosapentaenoic acid/d) in the ω-3 and LCHP+ω-3 diet groups or 6 g corn oil/d (placebo) in the CON and LCHP diet groups.

Results

Compared with the CON diet group, greater decreases in glycated hemoglobin (HbA1c) and fasting glucose were observed in all of the other 3 diet groups at 12 wk. Of note, HbA1c reduction in the LCHP+ω-3 diet group (-0.51%; 95% CI: -0.64%, -0.37%) was greater than that in the LCHP (P = 0.03) and ω-3 (P = 0.01) diet groups at 12 wk. In terms of fasting glucose, only the LCHP+ω-3 diet group showed a significant decrease at 4 wk (P = 0.03 compared with CON). Moreover, the reduction in fasting glucose in the LCHP+ω-3 diet group (-1.32 mmol/L; 95% CI: -1.72, -0.93 mmol/L) was greater than that in the LCHP (P = 0.04) and ω-3 (P = 0.03) diet groups at 12 wk.

Conclusions

The LCHP+ω-3 diet provided greater effects on HbA1c and fasting glucose and faster effects on fasting glucose than both the LCHP and ω-3 diets, indicating the potential necessity of combining an LCHP diet with ω-3 PUFAs in T2D control. This trial was registered at chictr.org.cn/ as ChiCTR-TRC-14004704.

Dietary polyunsaturated fatty acids mediate the inverse association of stearoyl-CoA desaturase activity with the risk of fatty liver in dyslipidaemic individuals

PURPOSE

The activity of stearoyl-CoA desaturase-1 (SCD1) is increased in non-alcoholic fatty liver disease (NAFLD). Polyunsaturated fatty acids (PUFA) inhibit SCD1, but clinical studies on whether all dietary PUFA species are equal in SCD1 inhibition are scarce. Serum phospholipids are an objective proxy of dietary intake of plant-derived PUFA (C18:2n-6, C18:3n-3) and marine-derived PUFA (C20:5n-3, C22:6n-3). In 355 participants with primary dyslipidemia, we cross-sectionally investigated whether the presumed association between surrogate markers of NAFLD and SCD1 activity is mediated by intake of PUFA, and, if it is, what PUFA species are relevant in this regard.

METHODS

We determined the fatty acid profile of serum phospholipids by gas chromatography, and used the ratio C16:1n-7/C16:0 as a marker of SCD1 activity. NAFLD was diagnosed by values ≥ 60 in the fatty liver index (FLI), a surrogate recently validated against ultrasonography.

RESULTS

FLI ≥ 60 was detected in 37.5% (n = 133) of study participants. In a multivariate model, SCD1 activity showed an expected significant association with the risk of NAFLD, with odds ratio (OR) (95% confidence interval) of 1.44 (1.04-2.01) for each 0.01 increase. In a model further allowing the stepwise inclusion of plant-derived PUFA, marine-derived PUFA, and total PUFA (vegetable + marine), total PUFA replaced SCD1 activity as a significant (inverse) association of NAFLD, with OR 0.89 (0.81-0.99).

CONCLUSIONS

Total PUFA, regardless of their origin, mediates the relationship between SCD1 activity and NAFLD. This provides a new insight in the protective effects of PUFA against NAFLD, heretofore mostly focussed on PUFA species from marine origin.

Cardio-Metabolic Benefits of Plant-Based Diets

Cardio-metabolic disease, namely ischemic heart disease, stroke, obesity, and type 2 diabetes, represent substantial health and economic burdens. Almost one half of cardio-metabolic deaths in the U.S. might be prevented through proper nutrition. Plant-based (vegetarian and vegan) diets are an effective strategy for improving nutrient intake. At the same time, they are associated with decreased all-cause mortality and decreased risk of obesity, type 2 diabetes, and coronary heart disease. Evidence suggests that plant-based diets may reduce the risk of coronary heart disease events by an estimated 40% and the risk of cerebral vascular disease events by 29%. These diets also reduce the risk of developing metabolic syndrome and type 2 diabetes by about one half. Properly planned vegetarian diets are healthful, effective for weight and glycemic control, and provide metabolic and cardiovascular benefits, including reversing atherosclerosis and decreasing blood lipids and blood pressure. The use of plant-based diets as a means of prevention and treatment of cardio-metabolic disease should be promoted through dietary guidelines and recommendations.

Effect of n-3 Polyunsaturated Fatty Acid Supplementation on Metabolic and Inflammatory Biomarkers in Type 2 Diabetes Mellitus Patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is accompanied by chronic low-grade inflammation, with an imbalance in the secretion of adipokines and, worsening insulin resistance. Supplementation with n-3 PUFA in T2DM decreases inflammatory markers, the purpose of the study was to investigate the effect of n-3 PUFA supplementation on adipokines, metabolic control, and lipid profile in T2DM Mexican adults.

METHODS

In a randomized, single-blind, placebo-controlled pilot study, 54 patients with T2DM received 520 mg of DHA + EPA-enriched fish-oil (FOG) or a placebo (PG) daily. Baseline and 24-week anthropometric and biochemical measurements included glucose, insulin, glycosylated hemoglobin (Hb1Ac), leptin, adiponectin, resistin, and lipid profile; n-3 PUFA intake was calculated in g/day.

RESULTS

Waist circumference and blood glucose showed significant reductions in the FOG group (p = 0.001 and p = 0.011, respectively). Hb1Ac (p = 0.009 and p = 0.004), leptin (p < 0.000 and p < 0.000), and leptin/adiponectin ratio (p < 0.000 and p < 0.000) decreased significantly in both groups after 24 weeks (FOG and PG respectively). Serum resistin (FOG p < 0.000 and PG p = 0.001), insulin (FOG p < 0.000 and PG p < 0.000), and HOMA-IR (FOG p = 0.000 and PG p < 0.000) increased significantly in both groups. FOG had an overall improvement in the lipid profile with a significant decrease in triacylgycerols (p = 0.002) and atherogenic index (p = 0.031); in contrast, the PG group had increased total cholesterol (p < 0.000), non-HDL cholesterol (p < 0.000), and atherogenic index (p = 0.017).

CONCLUSIONS

We found a beneficial effect of n-3 PUFA supplementation on waist circumference, glucose, Hb1Ac, leptin, leptin/adiponectin ratio, and lipid profile, without significant changes in adiponectin, and increases in resistin, insulin, and HOMA-IR in both groups.

Long-chain n-3 PUFA supplied by the usual diet decrease plasma stearoyl-CoA desaturase index in non-hypertriglyceridemic older adults at high vascular risk

BACKGROUND & AIMS

The activity of stearoyl-CoA desaturase-1 (SCD1), the central enzyme in the synthesis of monounsaturated fatty acids (MUFA), has been associated with de novo lipogenesis. In experimental models SCD1 is down-regulated by polyunsaturated fatty acids (PUFA), but clinical studies are scarce. The effect of long-chain n-3 PUFA (LCn-3PUFA) supplied by the regular diet, in the absence of fatty fish or fish oil supplementation, remains to be explored.

METHODS

We related 1-y changes in plasma SCD1 index, as assessed by the C16:1n-7/C16:0 ratio, to both adiposity traits and nutrient intake changes in a sub-cohort (n = 243) of non-hypertriglyceridemic subjects of the PREDIMED (PREvención con DIeta MEDiterranea) trial.

RESULTS

After adjustment for confounders, including changes in fasting triglycerides, plasma SCD1 index increased in parallel with body weight (0.221 [95% confidence interval, 0.021 to 0.422], P = 0.031) and BMI (0.115 [0.027 to 0.202], P = 0.011). Additionally, dietary LCn-3PUFA (but not MUFA or plant-derived PUFA) were associated with decreased plasma SCD1 index (-0.544 [-1.044 to -0.043], P = 0.033, for each 1 g/d-increase in LCn-3PUFA). No associations were found for other food groups, but there was a trend for fatty fish intake (-0.083 [-0.177 to 0.012], P = 0.085, for each 10 g/d-increase).

CONCLUSIONS

Our data add clinical evidence on the down-regulation of plasma SCD1 index by LCn-3PUFA in the context of realistic changes in fish consumption in the customary, non-supplemented diet.

CLINICAL TRIAL REGISTRATION

http://www.Controlled-trials.com/ISRCTN35739639.

Update on the treatment of type 2 diabetes mellitus

To achieve good metabolic control in diabetes and keep long term, a combination of changes in lifestyle and pharmacological treatment is necessary. Achieving near-normal glycated hemoglobin significantly, decreases risk of macrovascular and microvascular complications. At present there are different treatments, both oral and injectable, available for the treatment of type 2 diabetes mellitus (T2DM). Treatment algorithms designed to reduce the development or progression of the complications of diabetes emphasizes the need for good glycaemic control. The aim of this review is to perform an update on the benefits and limitations of different drugs, both current and future, for the treatment of T2DM. Initial intervention should focus on lifestyle changes. Moreover, changes in lifestyle have proven to be beneficial, but for many patients is a complication keep long term. Physicians should be familiar with the different types of existing drugs for the treatment of diabetes and select the most effective, safe and better tolerated by patients. Metformin remains the first choice of treatment for most patients. Other alternative or second-line treatment options should be individualized depending on the characteristics of each patient. This article reviews the treatments available for patients with T2DM, with an emphasis on agents introduced within the last decade.

Effects of sardine-enriched diet on metabolic control, inflammation and gut microbiota in drug-naïve patients with type 2 diabetes: a pilot randomized trial

BACKGROUND

Nutrition therapy is the cornerstone of treating diabetes mellitus. The inclusion of fish (particularly oily fish) at least two times per week is recommended by current international dietary guidelines for type 2 diabetes. In contrast to a large number of human studies examining the effects of oily fish on different cardiovascular risk factors, little research on this topic is available in patients with type 2 diabetes. The aims of this pilot study were to investigate the effects of a sardine-enriched diet on metabolic control, adiponectin, inflammatory markers, erythrocyte membrane fatty acid (EMFA) composition, and gut microbiota in drug-naïve patients with type 2 diabetes.

METHODS

35 drug-naïve patients with type 2 diabetes were randomized to follow either a type 2 diabetes standard diet (control group: CG), or a standard diet enriched with 100 g of sardines 5 days a week (sardine group: SG) for 6 months. Anthropometric, dietary information, fasting glycated hemoglobin, glucose, insulin, adiponectin, inflammatory markers, EMFA and specific bacterial strains were determined before and after intervention.

RESULTS

There were no significant differences in glycemic control between groups at the end of the study. Both groups decreased plasma insulin (SG: -35.3%, P = 0.01, CG: -22.6%, P = 0.02) and homeostasis model of assessment--insulin resistance (HOMA-IR) (SG: -39.2%, P = 0.007, CG: -21.8%, P = 0.04) at 6-months from baseline. However only SG increased adiponectin in plasma compared to baseline level (+40.7%, P = 0.04). The omega-3 index increased 2.6% in the SG compared to 0.6% in the CG (P = 0.001). Both dietary interventions decreased phylum Firmicutes (SG and CG: P = 0.04) and increased E. coli concentrations (SG: P = 0.01, CG: P = 0.03) at the end of the study from baseline, whereas SG decreased Firmicutes/Bacteroidetes ratio (P = 0.04) and increased Bacteroides-Prevotella (P = 0.004) compared to baseline.

CONCLUSIONS

Although enriching diet with 100 g of sardines 5 days a week during 6 months to a type 2 diabetes standard diet seems to have neutral effects on glycemic control in drug-naïve patients with type 2 diabetes, this nutritional intervention could have beneficial effects on cardiovascular risk. Furthermore, both dietary interventions decreased HOMA-IR and altered gut microbiota composition of drug-naïve patients with type 2 diabetes.

TRIAL REGISTRATION

Trial number and name of the registry: NCT02294526, ClinicalTrials.gov.

Changes in plasma metabolites and glucose homeostasis during omega-3 polyunsaturated fatty acid supplementation in women with polycystic ovary syndrome

Background

Both fish (FO) and flaxseed oils (FLX) are n-3 polyunsaturated fatty acids (PUFA). Fish oil contains long chain while FLX contains essential n-3 PUFA. We demonstrated that FO altered insulin secretion and resistance in polycystic ovary syndrome (PCOS) women but FLX did not. Surprisingly, the effects of FO were similar to those of the n-6 PUFA-rich soybean oil (SBO). Since increased branched chain (BCAA) and aromatic amino acids (AA) affect insulin secretion and resistance, we investigated whether FO, FLX and /or SBO affect plasma metabolites, especially AA.

Methods and findings

In this six-week, randomized, 3-parallel arm, double-blinded study, 54 women received 3.5 g/day FO, FLX or SBO. In 51 completers (17 from each arm), fasting plasma metabolites were measured at the beginning and at the end.

As compared to FLX, FO and SBO increased insulin response and resistance as well as several BCAA and aromatic AA. Pathway analysis indicated that FO exerted the largest biochemical impact, affecting AA degradation and biosynthesis, amine, polyamine degradation and alanine, glycine, l-carnitine biosynthesis and TCA cycle, while FLX had minimal impact affecting only alanine biosynthesis and l-cysteine degradation.

Conclusion

Effects of FO and SBO on plasma AA were similar and differed significantly from those of the FLX. The primary target of dietary PUFA is not known. Dietary PUFA may influence insulin secretion and resistance directly and alter plasma AA indirectly. Alternatively, as a novel concept, dietary PUFA may directly affect AA metabolism and the changes in insulin secretion and resistance may be secondary.

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Increased serum branched chain amino acids (BCAA) and aromatic amino acids are associated with insulin resistance and type 2 diabetes.

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Although both fish oil (FO) and flaxseed oil (FLX) are n-3 PUFA, FO contains the long chain, while FLX contains the essential n-3 PUFA.

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We compared the effects of different PUFAs on plasma metabolites in women with insulin resistance.

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Fish oil, but not FLX, increased plasma BCAA, and insulin resistance and secretion, indicating differential effects of essential vs. long chain n-3 PUFA.

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It is possible that effects of FO on insulin resistance and secretion may have been indirect, through its actions on BCAA metabolism.

Effect of Increasing Doses of Linoleic and α-Linolenic Acids on High-Fructose and High-Fat Diet Induced Metabolic Syndrome in Rats

Doses and ratio of linoleic acid (LA) and α-linolenic acid (ALA) preventing metabolic syndrome (MS) were investigated. SD rats were fed (i) basal diet, (ii) high-fructose and high-fat diet (HFFD), (iii) HFFD with increasing-dose LA (0.75 energy-% ALA + 3, 6, 9, 12, 15, and 30 energy-% LA), and (iv) HFFD with increasing-dose ALA (6 energy-% LA + 0.3, 0.5, 0.75, 1.5, 2.25, and 3.75 energy-% ALA) for 18 weeks. Results showed 6, 12, 15, and 30 energy-% LA significantly ameliorated central obesity, hyperlipidemia, glucose homeostasis, and leptin status; 0.5 and 0.75 energy-% ALA significantly improved insulin sensitivity, adiponectin, and anti-inflammatory status. Moreover, high intakes of ALA (1.5, 2.25, and 3.75 energy-%) presented a pro-oxidant activity. In conclusion, dose instead of ratio determines the prevention of MS. The optimal doses are 6 energy-% LA and 0.75 energy-% ALA; high intakes of ALA may have side effects.

Fish Oil-Rich Diet Promotes Hematopoiesis and Alters Hematopoietic Niche

The self-renewal and differentiation of hematopoietic stem cells (HSCs) in bone marrow are essential to replenish all blood cell types, but how this process is influenced by diet remains largely unclear. Here we show that a diet rich in fish oils promotes self-renewal of HSCs and extramedullary hematopoiesis. Chronic intake of a fish oil-rich diet increases the abundance of HSCs, alters the hematopoietic microenvironment, and, intriguingly, induces the expression of matrix metalloproteinase 12 (MMP12) in the bone marrow. Pointing to a direct effect of fish oil on MMP12 expression, omega-3 polyunsaturated fatty acids induce the expression of MMP12 in a dose-dependent manner in bone marrow cells. Importantly, down-regulation of MMP12 activity using an MMP12-specific inhibitor attenuates diet-induced myelopoiesis in both bone marrow and spleen. Thus, a fish oil-rich diet promotes hematopoiesis in the bone marrow and spleen, in part via the activity of MMP12. Taken together, these data provide new insights into diet-mediated regulation of hematopoiesis.

Influence of dietary intake of fish oil, magnesium, and zinc on metabolic parameters among individuals tested for diabetes

OBJECTIVE

The aim of this study was to assess the significance and degree of correlation between the intake of fish oil, magnesium (Mg), and zinc (Zn) and metabolic parameters.

METHODS

Correlation coefficients among nutrient intake and physical and laboratory parameters were determined using Spearman's rho (ρ) test or a multiple regression model among Japanese individuals (male:female, 37:66; median age, 55 y) who completed a semiquantitative food questionnaire and underwent testing for diabetes. Individuals with diabetes were excluded.

RESULTS

Spearman's test revealed several weak but significant correlations between intake of fish oil including ω-3 polyunsaturated fatty acids (PUFAs) and various metabolic parameters. The test showed that Zn intake in women significantly correlated with reduced systolic blood pressure (SBP), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γ-GPT), and homeostasis model assessment-insulin resistance (HOMA-IR). Multivariate analysis revealed that intake of fish oil, eicosapentaenoic acid (EPA), and Zn was significantly associated with increased serum levels of high-density lipoprotein cholesterol (HDL-C; fish oil versus HDL-C, P = 0.0438; 95% confidence interval [CI], 0.0055-0.3724; EPA versus HDL-C, P = 0.0439; 95% CI, 0.0053-0.3724; Zn versus HDL-C, P = 0.0041; 95% CI, 0.0890-0.4609). Multivariate analysis revealed that ω-3 PUFAs were associated with decreased serum ALT levels (P = 0.0240; 95% CI, -5.000 to -0.0367) and that Zn correlated with SBP (P = 0.0239; 95% CI, -0.5149 to -0.0377) in women.

CONCLUSION

Intake of fish oil, Mg, and Zn was associated with some metabolic parameters. Abundant intake of fish oil including ω-3 PUFAs and Zn can exert antiarteriosclerotic effects through increasing serum levels of HDL-C. ω-3 PUFAs can reduce liver inflammation and Zn can reduce SBP in women.

Effects of whole grain, fish and bilberries on serum metabolic profile and lipid transfer protein activities: a randomized trial (Sysdimet)

OBJECTIVE

We studied the combined effects of wholegrain, fish and bilberries on serum metabolic profile and lipid transfer protein activities in subjects with the metabolic syndrome.

METHODS

Altogether 131 subjects (40-70 y, BMI 26-39 kg/m(2)) with impaired glucose metabolism and features of the metabolic syndrome were randomized into three groups with 12-week periods according to a parallel study design. They consumed either: a) wholegrain and low postprandial insulin response grain products, fatty fish 3 times a week, and bilberries 3 portions per day (HealthyDiet), b) wholegrain and low postprandial insulin response grain products (WGED), or c) refined wheat breads as cereal products (Control). Altogether 106 subjects completed the study. Serum metabolic profile was studied using an NMR-based platform providing information on lipoprotein subclasses and lipids as well as low-molecular-weight metabolites.

RESULTS

There were no significant differences in clinical characteristics between the groups at baseline or at the end of the intervention. Mixed model analyses revealed significant changes in lipid metabolites in the HealthyDiet group during the intervention compared to the Control group. All changes reflected increased polyunsaturation in plasma fatty acids, especially in n-3 PUFAs, while n-6 and n-7 fatty acids decreased. According to tertiles of changes in fish intake, a greater increase of fish intake was associated with increased concentration of large HDL particles, larger average diameter of HDL particles, and increased concentrations of large HDL lipid components, even though total levels of HDL cholesterol remained stable.

CONCLUSIONS

The results suggest that consumption of diet rich in whole grain, bilberries and especially fatty fish causes changes in HDL particles shifting their subclass distribution toward larger particles. These changes may be related to known protective functions of HDL such as reverse cholesterol transport and could partly explain the known protective effects of fish consumption against atherosclerosis.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov NCT00573781.

Dietary risk factors for the development of insulin resistance in adolescent girls: a 3-year prospective study

OBJECTIVE

Identifying risk factors for insulin resistance in adolescence could provide valuable information for early prevention. The study sought to identify risk factors for changes in insulin resistance and fasting blood glucose levels.

DESIGN

Prospective cohort of girls participating in the National Heart, Lung, and Blood Institute Growth and Health Study.

SETTING USA SUBJECTS

Adolescent girls (n 774) assessed at the ages of 16-17 and 18-19 years. Over a 3-year period, measurements of fasting blood glucose and insulin and serum cotinine were taken, and dietary intake (3 d food diary), smoking status and physical activity levels were self-reported.

RESULTS

Improvements in homeostasis model assessment of insulin resistance (HOMA-IR) were associated with increases in the percentage of energy intake from polyunsaturated fats (β = -3·33, 95% CI -6·28, -0·39, P = 0·03) and grams of soluble fibre (β = -5·20, 95% CI -9·81, -0·59, P = 0·03) between the ages of 16-17 and 18-19 years; with similar findings for insulin. Transitioning into obesity was associated with an increase in insulin (β = 6·34, 95% CI 2·78, 9·91, P < 0·001) and HOMA-IR (β = 28·77, 95% CI 8·13, 49·40, P = 0·006). Serum cotinine concentrations at 16-17 years, indicating exposure to tobacco, were associated with large increases (β = 15·43, 95% CI 6·09, 24·77, P < 0·001) in fasting blood glucose concentrations.

CONCLUSIONS

Increases in the percentage of energy from polyunsaturated fat and fibre, and avoidance of excess weight gain and tobacco exposure, could substantially reduce the risk of insulin resistance in late adolescence.

Why fish oil fails: a comprehensive 21st century lipids-based physiologic analysis

The medical community suffered three significant fish oil failures/setbacks in 2013. Claims that fish oil's EPA/DHA would stop the progression of heart disease were crushed when The Risk and Prevention Study Collaborative Group (Italy) released a conclusive negative finding regarding fish oil for those patients with high risk factors but no previous myocardial infarction. Fish oil failed in all measures of CVD prevention-both primary and secondary. Another major 2013 setback occurred when fish oil's DHA was shown to significantly increase prostate cancer in men, in particular, high-grade prostate cancer, in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) analysis by Brasky et al. Another monumental failure occurred in 2013 whereby fish oil's EPA/DHA failed to improve macular degeneration. In 2010, fish oil's EPA/DHA failed to help Alzheimer's victims, even those with low DHA levels. These are by no means isolated failures. The promise of fish oil and its so-called active ingredients EPA / DHA fails time and time again in clinical trials. This lipids-based physiologic review will explain precisely why there should have never been expectation for success. This review will focus on underpublicized lipid science with a focus on physiology.

Serum fatty acid patterns, insulin sensitivity and the metabolic syndrome in individuals with chronic kidney disease

OBJECTIVES

The causes of the multiple metabolic disorders of individuals with chronic kidney disease (CKD) are not fully known. We investigated the relationships between dietary fat quality, the metabolic syndrome (MetS), insulin sensitivity and inflammation in individuals with CKD.

SUBJECTS

Two population-based surveys were conducted in elderly Swedish individuals (aged 70 years) with serum cystatin C-estimated glomerular filtration rate <60 mL min(-1) /1.73 m2: the Uppsala Longitudinal Study of Adult Men (ULSAM) and the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) surveys. The present population comprised 274 men and 187 subjects (63% women) from the ULSAM and PIVUS cohorts, respectively.

DESIGN

Factor analyses of serum fatty acids were used to evaluate dietary fat quality. Insulin sensitivity was measured by homeostasis model assessment of insulin resistance (IR) and, in ULSAM, also by euglycaemic clamp.

RESULTS

Factor analyses generated two fatty acid patterns of (i) low linoleic acid (LA)/high saturated fatty acid (SFA) or (ii) high n-3 polyunsaturated fatty acid (n-3 PUFA) levels. In both surveys, the low LA/high SFA pattern increased the odds of having MetS [adjusted odds ratio 0.60 [95% confidence interval (CI) 0.44-0.81] and 0.45 (95% CI 0.30-0.67) per SD decrease in factor score in the ULSAM and PIVUS surveys, respectively] and was directly associated with both IR and C-reactive protein. The n-3 PUFA pattern was not consistently associated with these risk factors.

CONCLUSIONS

A serum fatty acid pattern reflecting low LA and high SFA was strongly associated with MetS, IR and inflammation in two independent surveys of elderly individuals with CKD. At present, there are no specific dietary guidelines for individuals with CKD; however, these findings indirectly support current recommendations to replace SFAs with PUFAs from vegetable oils.

Nutrition therapy recommendations for the management of adults with diabetes

There is no standard meal plan or eating pattern that works universally for all people with diabetes. In order to be effective, nutrition therapy should be individualized for each patient/client based on his or her individual health goals; personal and cultural preferences; health literacy and numeracy; access to healthful choices; and readiness, willingness, and ability to change. Nutrition interventions should emphasize a variety of minimally processed nutrient dense foods in appropriate portion sizes as part of a healthful eating pattern and provide the individual with diabetes with practical tools for day-to-day food plan and behavior change that can be maintained over the long term.

Identification and quantitation of fatty acid double bond positional isomers: a shotgun lipidomics approach using charge-switch derivatization

The specific locations of double bonds in mammalian lipids have profound effects on biological membrane structure, dynamics and lipid second messenger production. Herein, we describe a shotgun lipidomics approach that exploits charge-switch derivatization with N-(4-aminomethylphenyl) pyridinium (AMPP) and tandem mass spectrometry for identification and quantification of fatty acid double bond positional isomers. Through charge-switch derivatization of fatty acids followed by positive-ion mode ionization and fragmentation analysis, a marked increase in analytic sensitivity (low fmol/μL) and the identification of double bond positional isomers can be obtained. Specifically, the locations of proximal double bonds in AMPP-derivatized fatty acids are identified by diagnostic fragment ions resulting from the markedly reduced 1,4-hydrogen elimination from the proximal olefinic carbons. Additional fragmentation patterns resulting from allylic cleavages further substantiated the double bond position assignments. Moreover, quantification of fatty acid double bond positional isomers is achieved by the linear relationship of the normalized intensities of characteristic fragment ions vs the isomeric compositions of discrete fatty acid positional isomers. The application of this approach for the analysis of fatty acids in human serum demonstrated the existence of two double bond isomers of linolenic acid (i.e., Δ(6,9,12) 18:3, γ-linolenic acid (GLA), and Δ(9,12,15) 18:3, α-linolenic acid (ALA)). Remarkably, the isomeric ratio of GLA vs ALA esterified in neutral lipids was 3-fold higher than the ratio of their nonesterified moieties. Through this developed method, previously underestimated or unidentified alterations in fatty acid structural isomers can be determined facilitating the identification of novel biomarkers and maladaptive alterations in lipid metabolism during disease.

Concurrent physical activity modifies the association between n3 long-chain fatty acids and cardiometabolic risk in midlife adults

Greater consumption of n3 (ω3) polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can reduce risk for cardiovascular disease events, yet their effects on metabolic risk factors and diabetes remain unclear. This cross-sectional study used a community volunteer sample to test whether the associations between n3 fatty acids and cardiometabolic risk vary as a function of physical activity. Participants were 344 generally healthy adults, 30-54 y of age, not taking fish oil supplements or confounding medications. Serum phospholipid EPA and DHA were used together (EPA+DHA) as a biomarker of n3 fatty acid exposure. Cardiometabolic risk was calculated as a continuous measure based on standardized distributions of blood pressure, waist circumference, HDL cholesterol, triglycerides, glucose, and a simple count of risk factors. Insulin resistance was estimated from the homeostatic model assessment. Physical activity was found to predict cardiometabolic risk (P ≤ 0.02) and insulin resistance (P ≤ 0.02) and to moderate the association between EPA+DHA and both cardiometabolic risk (P-interaction ≤ 0.02) and insulin resistance (P-interaction ≤ 0.02). Specifically, higher EPA+DHA was associated with lower cardiometabolic risk and insulin resistance in persons engaged in regular physical activity but not in relatively inactive individuals. These findings were noted in several components of cardiometabolic risk, in men and women separately, and in models adjusted for overall diet quality. In midlife adults, habitual physical activity may be necessary to unmask the salutary effects of n3 fatty acids on cardiometabolic risk and insulin resistance.

Stearidonic and γ-linolenic acids in echium oil improves glucose disposal in insulin resistant monkeys

Echium oil (EO) contains stearidonic acid (18:4), a n-3 polyunsaturated fatty acids (PUFAs), and gamma-linolenic acids (18:3), a n-6 PUFA that can be converted to long chain (LC)-PUFAs. We aimed to compare a safflower oil (SO)-enriched diet to EO- and fish oil (FO)-enriched diets on circulating and tissue PUFAs levels and glycemic, inflammatory, and cardiovascular health biomarkers in insulin resistant African green monkeys. In a Latin-square cross-over study, eight monkeys consumed matched diets for 6 weeks with 3-week washout periods. Monkeys consuming FO had significantly higher levels of n-3 LC-PUFAs and EO supplementation resulted in higher levels of circulating n-3 LC-PUFAs and a significant increase in dihomo-gamma linolenic acid (DGLA) in red blood cells and muscle. Glucose disposal was improved after EO consumption. These data suggest that PUFAs in EO supplementation have the capacity to alter circulating, RBC and muscle LC-PUFA levels and improve glucose tolerance in insulin-resistant monkeys.

Fish consumption, omega-3 fatty acids, and environmental contaminants in relation to low-grade inflammation and early atherosclerosis

BACKGROUND

Fish consumption and omega-3 polyunsaturated fatty acid (PUFA) intake are shown to protect from cardiovascular diseases (CVD). However, most fish contain environmental contaminants such as dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and methylmercury (MeHg) that may have adverse effects on cardiovascular health.

OBJECTIVE

Our aim was to elucidate the associations of fish consumption, omega-3 PUFAs, environmental contaminants with low-grade inflammation, early atherosclerosis, and traditional CVD risk factors.

METHODS

The Health 2000 survey participants (n=1173) represented the general Finnish population and the Fishermen study participants (n=255) represented a population with high fish consumption and high exposure to environmental contaminants. Model-adjusted geometric means and tests for linear trend were calculated for CVD risk factors by tertiles of fish consumption and serum omega-3 PUFAs, and additionally in the Fishermen study only, by tertiles of serum PCDD/F+PCB, and blood MeHg.

RESULTS

Serum triglyceride decreased across omega-3 PUFA tertiles in both sexes and studies. Insulin resistance, C-reactive protein, tumour necrosis factor α, and interleukin 6 decreased across omega-3 PUFA tertiles among the Health 2000 survey participants. Among the Fishermen study men, insulin resistance and arterial stiffness indicated by β-stiffness index tended to increase and the RR estimate for carotid artery plaque tended to decrease across tertiles of PCDD/F+PCB and MeHg.

CONCLUSION

Previously established hypotriglyceridemic and anti-inflammatory effects of omega-3 PUFAs were seen also in this study. The hypothesised favourable effect on insulin sensitivity and arterial elasticity was suggested to be counteracted by high exposure to environmental contaminants but the effect on plaque prevalence appeared not to be harmful.