DHA-rich fish oil reverses the detrimental effects of saturated fatty acids on postprandial vascular reactivity

Background: Experimental elevation of nonesterified fatty acids (NEFAs) impairs endothelial function, but the effect of NEFA composition is unknown. Objective: The objective was to test the effect of acute elevation of NEFAs enriched with either saturated fatty acids (SFAs) or SFAs with long-chain (LC) n−3 (omega-3) PUFAs on vascular function measured via flow-mediated dilatation (FMD), laser Doppler iontophoresis (LDI), and digital volume pulse (DVP). Design: In 59 subjects (30 men and 29 women), repeated oral fat feeding of either palm stearin (SFA) or palm stearin with DHA-rich fish oil (SFA + LC n−3 PUFA) was performed on 2 separate occasions with continuous heparin infusion to elevate NEFAs for a duration of 60 to 240 min. Vascular function was measured at baseline and at the end of NEFA elevation; venous blood was collected for measurement of lipids and circulating markers of endothelial function. Results: NEFA elevation during consumption of the SFA-rich drinks was associated with a marked impairment of FMD, whereas consumption of SFAs + LC n−3 PUFAs improved FMD response, with a mean (±SEM) difference of 2.06 ± 0.29% (P < 0.001). Positive correlations were found with percentage weight of LC n−3 PUFAs in circulating NEFAs and change in FMD response [Spearman's rho (rs) = 0.460, P < 0.001]. LDI measures increased during both treatments (P ≤ 0.026), and there was no change in DVP indexes. Conclusions: The composition of NEFAs can acutely affect FMD. The beneficial effect of LC n−3 PUFAs on postprandial vascular function warrants further investigation but may be mediated by nitric oxide–independent mechanisms. This trial is registered at clinicaltrials.gov as NCT01351324.

The impact of catechol-O-methyltransferase genotype on the acute responsiveness of vascular reactivity to a green tea extract

The beneficial effects of green tea catechins, such as the proposed improvement in endothelial function, may be influenced by phase II metabolism during and after absorption. The methylation enzyme, catechol-O-methyltransferase (COMT), has a missense mutation rs4680 (G to A), proposed to result in a 40 % reduction in enzyme activity. In the present pilot study, twenty subjects (ten of each homozygous COMT genotype) were recruited. Green tea extract capsules (836 mg green tea catechins) were given in a fasted state, and a high-carbohydrate breakfast was given after 60 min. Blood samples and vascular function measurements were taken at regular intervals. The change in digital volume pulse stiffness index (SI) from baseline was shown to be different between genotype groups at 120 and 240 min, with a lower SI in the GG individuals (P ≤ 0·044). The change in blood pressure from baseline also differed between genotype groups, with a greater increase in systolic (P = 0·023) and diastolic (P = 0·034) blood pressure at 120 min in the GG group. The AA group was shown to have a greater increase in insulin concentrations at 120 min (P = 0·019) and 180 min (P = 0·008) compared with baseline, despite similar glucose profiles. No genotypic differences were found in vascular reactivity measured using laser Doppler iontophoresis, total nitrite, lipids, plasma total antioxidant capacity or inflammatory markers after ingestion of the green tea extract. In conclusion, SI and insulin response to the glucose load differed between the COMT genotype groups, and this may be suggestive of a green tea extract and genotype interaction.

Attitudinal and demographic determinants of diet quality and implications for policy targeting

Background:  Poor diet quality is a major public health concern that has prompted governments to introduce a range of measures to promote healthy eating. For these measures to be effective, they should target segments of the population with messages relevant to their needs, aspirations and circumstances. The present study investigates the extent to which attitudes and constraints influence healthy eating, as well as how these vary by demographic characteristics of the UK population. It further considers how such information may be used in segmented diet and health policy messages. Methods:  A survey of 250 UK adults elicited information on conformity to dietary guidelines, attitudes towards healthy eating, constraints to healthy eating and demographic characteristics. Ordered logit regressions were estimated to determine the importance of attitudes and constraints in determining how closely respondents follow healthy eating guidelines. Further regressions explored the demographic characteristics associated with the attitudinal and constraint variables. Results:  People who attach high importance to their own health and appearance eat more healthily than those who do not. Risk-averse people and those able to resist temptation also eat more healthily. Shortage of time is considered an important barrier to healthy eating, although the cost of a healthy diet is not. These variables are associated with a number of demographic characteristics of the population; for example, young adults are more motivated to eat healthily by concerns over their appearance than their health. Conclusions:  The approach employed in the present study could be used to inform future healthy eating campaigns. For example, messages to encourage the young to eat more healthily could focus on the impact of diets on their appearance rather than health.

Milk in the diet: good or bad for vascular disease?

CVD still represent the greatest cause of death and disease burden in Europe and there remains uncertainty whether or not diets rich in milk and/or dairy products affect CVD risk. This paper reviews current evidence on this from prospective studies and the role of serum lipids and blood pressure as markers of CVD risk with such diets. Also the potential of animal nutrition-based approaches aimed at reducing CVD risk from consumption of milk and dairy products is outlined. Briefly, the evidence from prospective studies indicates that increased consumption of milk does not result in increased CVD risk and may give some long-term benefits, although few studies relate specifically to cheese and butter and more information on the relationship between milk/dairy product consumption and dementia is needed. Recent data suggest that the SFA in dairy products may be less of a risk factor than previously thought; although this is based on serum cholesterol responses which taken in isolation may be misleading. Milk and some dairy products have counterbalancing effects by reducing blood pressure and possibly BMI control. Despite this, animal nutrition strategies to replace some SFA in milk with cis-MUFA or cis-PUFA are extensive and intuitively beneficial, although this remains largely unproven, especially for milk. There is an urgent need for robust intervention studies to evaluate such milk-fat modifications using holistic markers of CVD risk including central arterial stiffness.

The impact of the catechol-O-methyltransferase genotype on vascular function and blood pressure after acute green tea ingestion

SCOPE: Evidence for the benefits of green tea catechins on vascular function is inconsistent, with genotype potentially contributing to the heterogeneity in response. Here, the impact of the catechol-O-methyltransferase (COMT) genotype on vascular function and blood pressure (BP) after green tea extract ingestion are reported. METHODS AND RESULTS: Fifty subjects (n = 25 of the proposed low-activity [AA] and of the high-activity [GG] COMT rs4680 genotype), completed a randomized, double-blind, crossover study. Peripheral arterial tonometry, digital volume pulse (DVP), and BP were assessed at baseline and 90 min after 1.06 g of green tea extract or placebo. A 5.5 h and subsequent 18.5 h urine collection was performed to assess green tea catechin excretion. A genotype × treatment interaction was observed for DVP reflection index (p = 0.014), with green tea extract in the AA COMT group attenuating the increase observed with placebo. A tendency for a greater increase in diastolic BP was evident at 90 min after the green tea extract compared to placebo (p = 0.07). A genotypic effect was observed for urinary methylated epigallocatechin during the first 5.5 h, with the GG COMT group demonstrating a greater concentration (p = 0.049). CONCLUSION: Differences in small vessel tone according to COMT genotype were evident after acute green tea extract.

The Glu298Asp single nucleotide polymorphism in the endothelial nitric oxide synthase gene differentially effects the vascular response to acute consumption of fruit and vegetable puree-based drinks

Scope Diets low in fruits and vegetables (FV) are responsible for 2.7 million deaths from cardiovascular diseases (CVD) and certain cancers annually. Many FV and their juices contain flavonoids, some of which increase endothelial nitric oxide synthase (eNOS) activity. A single nucleotide polymorphism in the eNOS gene, where thymine (T) replaces guanine (G) at position 894 predicting substitution of glutamate for aspartate at codon 298 (Glu298Asp), has been associated with increased CVD risk due to effects on nitric oxide synthesis and subsequently vascular reactivity. Individuals can be homozygous for guanine (GG), thymine (TT) or heterozygous (GT). Methods and results We investigated the effects of acute ingestion of a FV-puree-based-drink (FVPD) on vasodilation and antioxidant status in subjects retrospectively genotyped for this polymorphism. Healthy volunteers (n = 24; 11 GG, 11 GT, 2 TT) aged 30–70 were recruited to a randomized, controlled, crossover, acute study. We showed that acute consumption of 400 mL FVPD differentially affected individuals depending on their genotype. There was a significant genotype interaction for endothelium-dependent vasodilation measured by laser Doppler imaging with iontophoresis (P < 0.05) and ex vivo low-density lipoproteins (LDL) oxidation (P = 0.002). GG subjects had increased endothelium-dependent vasodilation 180 min (P = 0.028) and reduced ex vivo LDL oxidation (P = 0.013) after 60 min after FVPD compared with control, no differences were observed in GT subjects. Conclusion eNOS Glu298Asp genotype differentially affects vasodilation and ex vivo LDL oxidation after consumption of FV in the form of a puree-based drink.

New direct payments scheme: targeting and redistribution in the future CAP

The Commission has proposed that a revised version of the present regime of direct payments should be rolled forward into the post-2013 CAP. There would be a limited redistribution of funds between Member States. Thirty per cent of the budget would be allocated to a new greening component, which would be problematic in the WTO. Non-active farmers would not qualify for aid; and payments would be capped. Special schemes would be introduced for small farmers, for young new entrants, and for disadvantaged regions.

Glu298Asp polymorphism influences the beneficial effects of fish oil fatty acids on postprandial vascular function

Our objective was to determine whether the endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism influences vascular response to raised NEFA enriched with saturated fatty acids (SFA) or long-chain (LC) n-3 polyunsaturated fatty acids (PUFA). Subjects were prospectively recruited for genotype (Glu298, n = 30 and Asp298, n = 29; balanced for age and gender) consumed SFA on two occasions, with and without the substitution of 0.07 g fat/kg body weight with LC n-3 PUFA, and with heparin infusion to elevate NEFA. Endothelial function was measured before and after NEFA elevation (240 min), with blood samples taken every 30 min. Flow-mediated dilation (FMD) decreased following SFA alone and increased following SFA+LC n-3 PUFA. There were 2-fold differences in the change in FMD response to the different fat loads between the Asp298 and Glu298 genotypes (P = 0.002) and between genders (P < 0.02). Sodium nitroprusside-induced reactivity, measured by laser Doppler imaging with iontophoresis, was significantly greater with SFA+LC n-3 PUFA in all female subjects (P < 0.001) but not in males. Elevated NEFA influences both endothelial-dependent and endothelial-independent vasodilation during the postprandial phase. Effects of fat composition appear to be genotype and gender dependent, with the greatest difference in vasodilatory response to the two fat loads seen in the Asp298 females.

Acute and long-term effects of dietary fatty acids on vascular function in health and disease

Purpose of review: Vascular function is recognized as an early and integrative marker of cardiovascular disease. While there is consistent evidence that the quantity of dietary fat has significant effects on vascular function, the differential effects of individual fatty acids is less clear. This review summarizes recent evidence from randomly controlled dietary studies on the impact of dietary fatty acids on vascular function, as determined by flow-mediated dilatation (FMD). Recent findings: Critical appraisal is given to five intervention studies (one acute, four chronic) which examined the impact of long-chain n-3 polyunsaturated fatty acid [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] on FMD. In the acute setting, a high dose of long-chain n-3 polyunsaturated fatty acid (4.9 g per 70 kg man) improved postprandial FMD significantly, compared with a saturated fatty acid-rich meal in healthy individuals. In longer-term studies, there was limited evidence for a significant effect of EPA/DHA on FMD in diseased groups. Summary: The strongest evidence for the benefits of EPA/DHA on vascular function is in the postprandial state. More evidence from randomly controlled intervention trials with foods will be required to substantiate the long-term effects of EPA/DHA, to inform public health and clinical recommendations.

Fish oil fatty acids and vascular reactivity

Endothelial dysfunction and an associated increase in vascular tone are risk factors for cardiovascular disease and highly predictive of future cardiovascular events. A part of the benefits associated with increased intake of the long chain (LC) n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid and docosahexaenoic acid, found in fish oils is a positive impact on cardiovascular health. Here, the recent evidence from human observational and intervention trials are reviewed, and an insight into potential mechanisms underlying the impact of LC n-3 PUFA on vascular reactivity is provided.