Damian O. McCall

Dietary Intake of Fruits and Vegetables Improves Microvascular Function in Hypertensive Subjects in a Dose-Dependent Manner

Background— Observational evidence has consistently linked increased fruit and vegetable consumption with reduced cardiovascular morbidity; however, there is little direct trial evidence to support the concept that fruit and vegetable consumption improves vascular function. This study assessed the dose-dependent effects of a fruit and vegetable intervention on arterial health in subjects with hypertension. Methods and Results— After a 4-week run-in period during which fruit and vegetable intake was limited to 1 portion per day, participants were randomized to consume either 1, 3, or 6 portions daily for the next 8 weeks. Endothelium-dependent and -independent arterial vasodilator responses were assessed by venous occlusion plethysmography in the brachial circulation before and after intervention. Compliance was monitored with serial contemporaneous 4-day food records and by measuring concentrations of circulating dietary biomarkers. A total of 117 volunteers completed the 12-week study. Participants in the 1-, 3-, and 6-portions/d groups reported consuming on average 1.1, 3.2, and 5.6 portions of fruit and vegetables, respectively, and serum concentrations of lutein and &bgr;-cryptoxanthin increased across the groups in a dose-dependent manner. For each 1-portion increase in reported fruit and vegetable consumption, there was a 6.2% improvement in forearm blood flow responses to intra-arterial administration of the endothelium-dependent vasodilator acetylcholine (P=0.03). There was no association between increased fruit and vegetable consumption and vasodilator responses to sodium nitroprusside, an endothelium-independent vasodilator. Conclusions— The present study illustrates that among hypertensive volunteers, increased fruit and vegetable consumption produces significant improvements in an established marker of endothelial function and cardiovascular prognosis.

Micronutrients: dietary intake v. supplement use

Whilst clinical deficiency of micronutrients is uncommon in the developed world, a suboptimal intake of certain micronutrients has been linked with an increased risk of chronic diseases such as CVD and cancer. Attention has therefore focused on increasing micronutrient status in order to theoretically reduce chronic disease risk. Increasing micronutrient status can involve a number of approaches: increasing dietary intake of micronutrient-rich foods; food fortification; use of supplements. Observational cohort studies have demonstrated an association between high intakes of micronutrients such as vitamin E, vitamin C, folic acid and beta-carotene, and lower risk of CHD, stroke and cancer at various sites. However, randomised intervention trials of micronutrient supplements have, to date, largely failed to show an improvement in clinical end points. The discordance between data from cohort studies and the results so far available from clinical trials remains to be explained. One reason may be that the complex mixture of micronutrients found, for example, in a diet high in fruit and vegetables may be more effective than large doses of a small number of micronutrients, and therefore that intervention studies that use single micronutrient supplements are unlikely to produce a lowering of disease risk. Studies concentrating on whole foods (e.g. fruit and vegetables) or diet pattern (e.g. Mediterranean diet pattern) may be more effective in demonstrating an effect on clinical end points. The present review will consider the clinical trial evidence for a beneficial effect of micronutrient supplements on health, and review the alternative approaches to the study of dietary intake of micronutrients.

The assessment of vascular function during dietary intervention trials in human subjects.

The potential to reduce cardiovascular morbidity through dietary modification remains an area of intense clinical and scientific interest. Any putatively beneficial intervention should be tested within a randomised controlled trial which records appropriate endpoints, ideally incident CVD and death. However, the large sample sizes required for these endpoints and associated high costs mean that the majority of dietary intervention research is conducted over short periods among either healthy volunteers or those at only slightly increased risk, with investigators using a diverse range of surrogate measures to estimate arterial health in these studies. The present review identifies commonly employed techniques, discusses the relative merits of each and highlights emerging approaches.

Beneficial effect of a polyphenol-rich diet on cardiovascular risk: a randomised control trial

Objectives There is previous epidemiological evidence that intake of polyphenol-rich foods has been associated with reduced cardiovascular disease risk. We aimed to investigate the effect of increasing dietary polyphenol intake on microvascular function in hypertensive participants. Methods All participants completed a 4-week run-in phase, consuming <2 portions of fruit and vegetables (F&V) daily and avoiding berries and dark chocolate. Subjects were then randomised to continue with the low-polyphenol diet for 8 weeks or to consume a high-polyphenol diet of six portions F&V (including one portion of berries/day and 50 g of dark chocolate). Endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside) vasodilator responses were assessed by venous occlusion plethysmography. Compliance with the intervention was measured using food diaries and biochemical markers. Results Final analysis of the primary endpoint was conducted on 92 participants. Between-group comparison of change in maximum % response to ACh revealed a significant improvement in the high-polyphenol group (p=0.02). There was a significantly larger increase in vitamin C, carotenoids and epicatechin in the high-polyphenol group (between-group difference p<0.001; p<0.001; p=0.008, respectively). Conclusions This study has shown that increasing the polyphenol content of the diet via consumption of F&V, berries and dark chocolate results in a significant improvement in an established marker of cardiovascular risk in hypertensive participants. Trial registration number NCT01319786.

The relationship between microvascular endothelial function and carotid radial pulse wave velocity in patients with mild hypertension

Carotid-radial pulse wave velocity (CRPWV) can be measured rapidly using applanation tonometry and significantly higher values have been reported among patients with risk factors for vascular disease. Forearm blood flow responses to intrabrachial infusion of acetylcholine independently predict cardiovascular morbidity among hypertensive patients. We aimed to examine the relationship between CRPWV, a potentially informative, noninvasive measure and this more established parameter of arterial health. One hundred and fifteen mildly hypertensive individuals (67% men, mean (± SD) age 54 ± 8 years, mean (± SD) blood pressure (BP) 143 ± 16/83 ± 12 mmHg) were recruited from a weekly medical outpatient clinic. Each volunteer had CRPWV measured using sequential tonometry before forearm blood flow responses to intra-arterial, endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) vasodilators were assessed. There was a significant negative correlation between CRPWV and maximum forearm blood flow response to acetylcholine (r = −0.225, p = 0.016). This association remained significant in a multiple regression analysis (β = −0.213, p = 0.034). Mean arterial pressure and weight were additional independent predictors of CRPWV in this model. There was no such relationship between CRPWV and response to sodium nitroprusside (r = 0.088, p = 0.349). In patients with mild hypertension, a poor forearm blood flow response to acetylcholine independently predicted faster CRPWV, thus linking an established measure of microvascular endothelial function with a noninvasive index of conduit vessel stiffness.

107 Effect of a Polyphenol-rich Diet on Vascular Function and other Markers of Cardiovascular Risk

Introduction Observational evidence indicates that polyphenol-rich foods, in particular berries and dark chocolate, have the potential to influence cardiovascular disease (CVD) risk.There are few polyphenol dietary intervention studies of sufficiently robust design that assess the effect of polyphenol-rich foods on a range of cardiovascular endpoints in hypertensive patients.The aim of this study was to investigate the effect of increasing overall polyphenol dietary intake on microvascular function and other markers of cardiovascular risk in hypertensive participants. Methodology All participants commenced with a 4-week run-in phase, during which they were asked to exclude berries and dark chocolate and consume <2 portions of FandV.Subjects were then randomised to continue with the low polyphenol diet for a further 8 weeks, or to consume a high polyphenol diet of 6 portions fruit and vegetables (FandV) (including one portion of berries/day) and 50 g of dark chocolate.Endothelium-dependent and –independent vasodilator responses were assessed by venous occlusion plethysmography.Compliance was assessed with 4-day food diaries and biochemical markers including vitamin C, carotenoids and epicatechin.Other measures of cardiovascular risk included systolic blood pressure (SBP), lipid profile, hsCRP and PAI-1. Results A total of 99 volunteers completed the study, 6 were excluded from analysis due to elevated hsCRP.Between group comparison of maximum % response to acetylcholine (Ach) was significantly improved in the high polyphenol group (p = 0.02). Results were re-analysed with polyphenol-rich foods as a continuous variable, which revealed an absolute increase in the maximum response to Ach of 14.0% (p = 0.008) with an extra daily portion of FandV, and 112.5% (p = 0.020) with an extra daily portion of dark chocolate.There was no significant between group change in response to sodium nitroprusside. There was a strong trend in favour of a reduction in SBP (p = 0.059), as well as a significant decrease in total cholesterol (p = 0.042), in the high polyphenol group. PAI-1 and hsCRP did not improve with a polyphenol-rich diet, though there was a significant decrease in hsCRP in the low polyphenol group (p = 0.026).There was a significant increase in the high polyphenol group on between group comparison of vitamin C (p < 0.001), carotenoids (p < 0.001 for all except lycopene, p = 0.098) and epicatechin (p = 0.008), indicating good dietary compliance. Conclusions This work has shown that polyphenol-rich foods can effect a significant improvement in endothelium-dependent vasodilation following an 8-week intervention in hypertensive participants. These findings suggest that a well-tolerated, simple lifestyle modification can have a significant positive effect on markers of cardiovascular risk.

The effect of increased fruit and vegetable consumption on selected macronutrient and micronutrient intakes in four randomised-controlled trials

Fruit and vegetable (FV) intake is associated with reduced risk of a number of non-communicable diseases. Research tends to focus on antioxidants, flavonoids and polyphenols contained in FV as the main beneficial components to health; however, increasing FV may also alter overall diet profile. Extra FV may be substituted for foods thought to be less healthy, therefore altering the overall macronutrient and/or micronutrient content in the diet. This analysis merged dietary data from four intervention studies in participants with varying health conditions and examined the effect of increased FV consumption on diet profile. Dietary intake was assessed by either diet diaries or diet histories used in four FV randomised intervention studies. All food and drink intake recorded was analysed using WISP version 3.0, and FV portions were manually counted using household measures. Regression analysis revealed significant increases in intakes of energy (172 kJ (+41 kcal)), carbohydrate (+3·9 g/4184 kJ (1000 kcal)), total sugars (+6·0 g/4184 kJ (1000 kcal)) and fibre (+0·8 g/4184 kJ (1000 kcal)) and significant decreases in intakes of total fat (-1·4 g/4184 kJ (1000 kcal)), SFA (-0·6 g/4184 kJ (1000 kcal)), MUFA (-0·6 g/4184 kJ (1000 kcal)), PUFA (-0·1 g/4184 kJ (1000 kcal)) and starch (-2·1 g/4184 kJ (1000 kcal)) per one portion increase in FV. Significant percentage increases were also observed in vitamin C (+24 %) and -carotene (+20 %) intake, per one portion increase in FV. In conclusion, pooled analysis of four FV intervention studies, that used similar approaches to achieving dietary change, in participants with varying health conditions, demonstrated an increase in energy, total carbohydrate, sugars and fibre intake, and a decrease in fat intake alongside an expected increase in micronutrient intake.

35 The ambulatory cardiology unit; reduction of admissions and patient outcomes after 1 year

Introduction Recent developments in health service reform in Northern Ireland have seen the publication of the Bengoa Report, Systems, Not Structures, [1] which clearly states that “something very different has to happen at the delivery of care level.” Maintenance of existing services is not sustainable, and new methods of managing health care needs must be developed and evaluated. In 2015, the Belfast Trust piloted an Ambulatory Cardiology Unit (ACU). The ethos of ACU was to reduce pressure on the ED by providing a unit where rapid evaluation, treatment and follow-up could be provided by the Cardiology team, and at the same time reduce in-patient admissions to Cardiology beds. Here we report on the experience of an Ambulatory Cardiology Unit during the first year of service. Methods In order to measure the impact of the new service, a pre- post design was used for comparison with admission rates for 1 year after the initiation of ACU with admission rates in the preceding year, when there was no alternative to in-patient admission or out-patient care. In addition, a database was maintained for all ACU patients. This allowed the team to not only keep track of how many patients were seen and which conditions were treated in the ACU, but also allowed for follow-up for unscheduled care re-attendance, admission to hospital and mortality at 30 days, 6 months and 1 year. Results Activity; 946 new patients were seen in the first year. 698 reviews were carried out within the first year, bringing the total number of patient episodes to 1644. Reduction in admissions; There was an overall decrease in cardiology admissions of 13.5% over a period of 1 year. Admissions with AF were reduced by 24% and syncope by 29%. There was a reduction of 45% in admissions with Pericarditis. Outcomes at 30 days – unscheduled re-attenders, n=60. Admissions, n=25. Admissions with same condition as originally seen in ACU, n=4 (0.4% of patients seen). Mortality n=4 – none from the same cause as original referral. Outcomes at 6 months – Unscheduled re-attenders, n=217. Admissions, n=60. Admissions with same condition as originally seen in ACU, n=12 (1.3 % of patients seen). Mortality n=12–2 from the same cause as original referral ( end-stage HF). This equates to 0.2% of all patients seen. Conclusion Our unit has demonstrated that it has been possible to reduce admissions to cardiology in-patient beds by 13.5%, and patient outcomes indicate that the service is safe with only 1.7% admitted for the same reason as originally seen and only 0.2% mortality from the same condition as originally seen in ACU. Although this is a very small service, it has made an impact and demonstrates an alternative way of working. In the current climate, where ministers and clinicians agree that current methods of managing emergency care are unsustainable, our service represents a model which could be implemented by other specialities.