Biomedical subjects

I B Puddey

Publications and source records attributed to I B Puddey.

At least 19 recordsLinked to original sources

PubMed2006

Alcohol intake and incidence of coronary disease in Australian aborigines.

AIMS: To examine risk for coronary heart disease (CHD) and cardiovascular disease (CVD) in relation to alcohol in a cohort of Australian Aborigines. METHODS: In 1988-1989, alcohol intake, drinking pattern, and beverage preference were elicited by interviewer-administered questionnaire in Western Australian Aborigines (258 men, 256 women) and cardiovascular outcomes ascertained through linkage to mortality and hospital admission records to 2002. RESULTS: In proportional hazards models, risk for CHD, relative to lifetime abstainers, was significantly increased in ex-drinkers [Hazard ratio (HR) 2.29, 95% CL 1.23, 4.27], those drinking 41-60 g/day in men or 21-40 g/day in women (HR 2.80, 95% CL 1.04, 7.53), and those drinking >150 g/day for men or >100 g/day for women (HR 2.25, 95% CL 1.03, 4.90) with a J-shaped relationship. Low-to-moderate drinkers had lower waist girth, exercised more, and had a lower prevalence of overweight and smoking than at-risk drinkers. A preference for wine was associated with lower HR (0.28, 95% CL 0.10, 0.95). With CVD, only ex-drinkers showed significantly increased risk (HR 1.87, 95% CL 1.20, 2.91). CONCLUSIONS: More favourable health-related behaviours in low-to-moderate drinkers suggest that lower risk could be mediated by lifestyle, as proposed in other populations.

Adolescent↗

PubMed2006

Alcohol intake and incidence of coronary disease in Australian aborigines.

AIMS: To examine risk for coronary heart disease (CHD) and cardiovascular disease (CVD) in relation to alcohol in a cohort of Australian Aborigines. METHODS: In 1988-1989, alcohol intake, drinking pattern, and beverage preference were elicited by interviewer-administered questionnaire in Western Australian Aborigines (258 men and 256 women) and cardiovascular outcomes ascertained through linkage to mortality and hospital admission records to 2002. RESULTS: In proportional hazards models, risk for CHD, relative to lifetime abstainers, was significantly increased in ex-drinkers [Hazard ratio (HR), 2.29; 95% confidence intervals (CI), 1.23-4.27], those drinking 41-60 g/day in men or 21-40 g/day in women (HR 2.80; 95% CI, 1.04-7.53) and those drinking >150 g/day for men or >100 g/day for women (HR, 2.25; 95% CI, 1.03-4.90) with a J-shaped relationship. Low-to-moderate drinkers had lower waist girth, exercised more and had a lower prevalence of overweight and smoking than at-risk drinkers. A preference for wine was associated with lower HR (0.28; 95% CI, 0.10-0.95). With CVD, only ex-drinkers showed significantly increased risk (HR, 1.87; 95% CI, 1.20-2.91). CONCLUSIONS: More favourable health-related behaviours in low-to-moderate drinkers suggest that lower risk could be mediated by lifestyle, as proposed in other populations.

Adolescent↗

PubMed2006

Health-related behaviours as predictors of mortality and morbidity in Australian Aborigines.

OBJECTIVE: To examine predictors of coronary heart disease (CHD) and all-cause mortality in Aboriginal Australians. METHOD: In 1988-89, a survey of Western Australian Aborigines (256 women, 258 men) aged 15-88 years documented diet, alcohol and smoking habits. Linkage to mortality and hospital admissions to the end of 2002 provided longitudinal data for modelling of coronary heart disease endpoints and all-cause mortality using Cox regression. RESULTS: Coronary heart disease risk increased with smoking (HR 2.62, 95% CI: 1.19, 5.75), consumption of processed meats >once/week (HR 2.21, 95% CI: 1.05, 4.63), eggs >twice/week (HR 2.59, 95% CI: 1.11, 6.04) and using spreads on bread (HR 3.14. 95% CI: 1.03, 9.61). All-cause mortality risk was lower with exercise >once/week (HR 0.51, 95% CI 0.26, 1.05), increased in ex-drinkers (HR 3.66, 95% CI: 1.08, 12.47), heavy drinkers (HR 5.26, 95% CI: 1.46, 7.52) and with consumption of take away foods >nine times/month (HR 1.78, 95% CI 0.96, 3.29). Greater alcohol intake, smoking and adverse dietary choices clustered in 53% of men and 56% of women and increased risk of coronary heart disease (HR 2.1, 95% CI: 1.1, 4.0) and all-cause mortality (HR 2.3, 95% CI: 1.2, 4.2). CONCLUSION: Lifestyle in Aboriginal Australians predicts coronary heart disease and all-cause mortality. Clustering of adverse behaviours is common and increases risk of coronary heart disease and death.

Adolescent↗

PubMed2003

Controlled comparison of retention and adherence in home- vs center-initiated exercise interventions in women ages 40-65 years: The S.W.E.A.T. Study (Sedentary Women Exercise Adherence Trial).

BACKGROUND: In an 18-month exercise intervention in previously sedentary older women (40-65 years), we examined whether an initial 6 months of supervised exercise leads to greater long-term retention and adherence to regular physical activity than an unsupervised home-based program and whether these outcomes are influenced by the exercise intensity. METHODS: Women (N = 126) were recruited from the community and randomly assigned to either center-based or home-based exercise three times/week. The center-based group attended supervised sessions for 6 months, while after 10 initial sessions the home-based group exercised at home. After 6 months both groups were home-based for a further 12 months. Within each arm, subjects were further randomized to exercise at either moderate or vigorous intensity. RESULTS: The center-based group had higher retention than the home-based (97, 94, 81 versus 87, 76, and 61%) at 6, 12, and 18 months, respectively (P < 0.05). At 6 months, adherence was higher in the center-based group (84 versus 63%, P < 0.001) and energy expenditure was higher at 6 (P < 0.05) and 12 (P < 0.01) months. At 18 months, retention was higher with moderate exercise (P < 0.05), while adherence was similar with both intensities. CONCLUSION: An initial 6 months of center-based exercise enhanced retention in both the short and the long term and promoted short-term adherence and energy expenditure. Long-term, moderate exercise retained more subjects, but had little influence on adherence.

Adult↗

PubMed2003

Exercise behaviour change in 40 to 65-year-old women: The SWEAT Study (Sedentary Women Exercise Adherence Trial).

OBJECTIVE: The purpose of this study was to examine the relation between self-reported psychological processes and changes in exercise behaviour in an 18-month longitudinal stage-based intervention trial in 115 initially sedentary women aged 40-65 years. DESIGN: A two-way factorial design was used. METHODS: Participants were assigned randomly to either moderate or vigorous and either home or centre-based exercise. After six months, all participants exercised at home. Participants completed questionnaires at baseline, six, 12 and 18 months which assessed stage of exercise behaviour, self-efficacy, decisional balance and processes of change. RESULTS: 28 patterns of stage change were identified across the 18 months with 6.1% remaining sedentary and 45% demonstrating linear movement from contemplation to action to maintenance to continued maintenance. Two interpretable clusters were identified within both the contemplation (at baseline) and action (at six months) stages. Cluster membership, however, did not influence behaviour change. For participants demonstrating a linear pattern of change, self-efficacy for overcoming barriers and behavioural processes increased from contemplation to action. Self-efficacy for exercise competence increased from contemplation to action but was more pronounced for the vigorous exercise groups. Decisional balance showed a three-way interaction and there was no change for experimental processes. There was no change in any variable from action to maintenance. CONCLUSIONS: The intervention was seen to be effective regardless of location or intensity of exercise. The relevance of substages is questionable in stage-based interventions as women with a profile suggesting less readiness to change or sustain change were just as likely to adopt or maintain exercise.

Adult↗

PubMed2002

Persistence of the antihypertensive efficacy of amlodipine and nifedipine GITS after two 'missed doses': a randomised, double-blind comparative trial in Asian patients.

Suboptimal management of hypertension is often a result of poor patient compliance in the form of missed doses of their antihypertensive medication. This multicentre, randomised, double-blind, parallel-group trial was designed to compare the persistence of the antihypertensive efficacy of the amlodipine and nifedipine gastrointestinal therapeutic system (GITS) after two 'missed doses', and also to compare the drugs' overall efficacy and safety in Asian patients with mild-to-moderate essential hypertension. Following a 2-week placebo run-in period, 222 patients were randomised to receive either amlodipine (5 mg daily, increased after 6 weeks if necessary to 10 mg daily, n=109) or nifedipine GITS (30 mg daily, increased after 6 weeks if necessary to 60 mg daily; n=113) for 12 weeks. A placebo was then substituted for further 2 days with continuous ambulatory blood pressure (BP) monitoring. The increases in the last 9 h of mean ambulatory BP on day 2 after treatment withdrawal were significantly less with amlodipine than with nifedipine GITS: 4.4+/-7.0 vs 11.2+/-11.3 mmHg for systolic BP (P<or=0.0001) and 2.4+/-6.3 vs 6.0+/-6.0 mmHg for diastolic BP (P<or=0.0002). Significant differences between the two drugs in mean 24-h ambulatory BP levels were already evident on day 1 after withdrawal, even though there were no significant differences on the final day of treatment. No differences in safety parameters were observed, and neither drug caused any serious or severe treatment-related adverse events. In conclusion, amlodipine provides greater protection than nifedipine GITS against loss of BP control following missed doses.

Amlodipine↗

PubMed2002

Similarity in the distribution of F(2)-isoprostanes in the lipid subfractions of atherosclerotic plaque and in vitro oxidised low density lipoprotein.

Oxidation of low density lipoprotein (LDL) in vivo is thought to play a critical role in the initiation of atherosclerosis. F(2)-isoprostanes are compounds resulting from non-enzymatic oxidation of arachidonic acid and elevated levels are present in human atherosclerotic plaque. However, little is known about the formation of F(2)-isoprostanes in plaque lesions or their distribution in lipid subclasses. Given that LDL and tissue lipid subfractions (such as phospholipids, cholesterol esters and triglycerides) all contain significant levels of arachidonic acid, the aim of this study was to examine the relative distribution of F(2)-isoprostanes in the different lipid fractions of LDL oxidised in vitro, and compare this to the distribution in atherosclerotic plaque. The results reveal that while the majority of F(2)-isoprostanes are present in the phospholipid or surface lipid fractions, the core lipids (cholesterol esters/triglycerides) contribute at least 10% of the total F(2)-isoprostanes in both LDL oxidised in vitro and human atherosclerotic plaque. The remarkably similar profiles between the oxidised LDL and advanced atherosclerotic plaque suggests oxidation in vivo, is predominantly via non-enzymatic processes directed towards the surface lipids.

Arachidonic Acid↗

PubMed2001

Alcohol consumption and the risk of type 2 diabetes mellitus: atherosclerosis risk in communities study.

Evidence regarding the association between alcohol consumption and type 2 diabetes risk remains inconsistent, particularly with regard to male-female differences. The authors conducted a prospective study of type 2 diabetes risk associated with alcohol consumption in a cohort of 12,261 middle-aged participants of the Atherosclerosis Risk in Communities Study (1990-1998), who were followed between 3 and 6 years. Alcohol consumption at baseline was characterized into lifetime abstainers, former drinkers, and current drinkers of various levels. Incident diabetes was determined by blood glucose measurements and self-report. After adjustment for potential confounders, an increased risk of diabetes was found in men who drank >21 drinks/week when compared with men who drank < or =1 drink/week (odds ratio = 1.50, 95% confidence interval: 1.02, 2.20) while no significant association was found in women. This increased diabetes risk among men who drank >21 drinks/week was predominantly related to spirits rather than to beer or wine consumption. The relative odds of incident diabetes in a comparison of men who drank >14 drinks of spirits per week with men who were current drinkers but reported no regular use of spirits, beer, or wine were 1.82 (95% confidence interval: 1.14, 2.92). Results of this study support the hypothesis that high alcohol intake increases diabetes risk among middle-aged men. However, more moderate levels of alcohol consumption do not increase risk of type 2 diabetes in either middle-aged men or women.

Alcohol Drinking↗

PubMed2001

Red wine polyphenols, in the absence of alcohol, reduce lipid peroxidative stress in smoking subjects.

Phenolic compounds in red wine can exert antioxidant effects on in vitro lipoprotein oxidation. This has led to speculation that red wine consumption mediates unique anti-atherosclerotic effects compared to other alcoholic beverages. However, studies assessing the effects of red wine consumption on lipoprotein oxidation ex vivo have not been conclusive. The recent identification of the F2-isoprostanes as oxidative products of arachidonic acid has provided a reliable measure of in vivo lipid peroxidation. This randomized trial investigated changes in plasma and urinary F2-isoprostane concentrations following red wine, white wine, or dealcoholized red wine consumption in humans. Eighteen male smokers consumed, in random order, red wine, white wine, or dealcoholized red wine, for two weeks with one week washout between beverages. Plasma and urinary F2-isoprostane concentrations were measured before and after each beverage. Serum gamma-glutamyl transpeptidase (gamma-GT) and urinary 4-O -methylgallic acid were measured as markers of alcohol consumption and phenolic acid absorption, respectively. Plasma F2-isoprostanes (p < .05) decreased significantly with dealcoholized red wine but not with the alcohol-containing beverages. Urinary excretion of F2-isoprostanes showed a similar trend. gamma-GT decreased significantly with dealcoholized red wine and increased with both alcohol-containing beverages (p < .01). Urinary excretion of 4-O-methylgallic acid increased significantly (p < .001) in the 24 h urine samples following red wine or dealcoholized red wine ingestion, but not with white wine. Serum urate increased and beta-carotene decreased with both alcoholic beverages relative to dealcoholized red wine. There was no change in the antioxidants alpha- and gamma-tocopherol or vitamin C with any of the beverages. The results suggest that polyphenols in dealcoholized red wine can reduce in vivo lipid peroxidation as measured by F2-isoprostanes in smoking subjects. However, no reduction in lipid peroxidation was observed following red or white wine consumption, suggesting that any protective effects of wine drinking on cardiovascular disease are unlikely to be related to inhibition of lipid oxidation.

Adult↗

PubMed2001

Effects of regular ingestion of black tea on haemostasis and cell adhesion molecules in humans.

OBJECTIVE: To assess the effects in humans of regular ingestion of black tea on haemostasis-related variables and cell adhesion molecules. DESIGN: Twenty-two subjects were recruited from the general population to a randomised-controlled crossover study. Subjects stopped drinking tea, apart from that provided, for the duration of the study. During a 4-week baseline period all subjects drank 5 cups/day (250 ml) of hot water. The effects of 5 cups/day of black tea for 4 weeks were then compared with hot water. Platelet aggregation in response to three doses of collagen and ADP, plasma concentrations of coagulation and fibrinolytic factors (fibrinogen, factor VII, tPA, PAI-1) and plasma concentrations of cell adhesion molecules (soluble P-selectin, E-selectin, ICAM-1, VCAM-1) were assessed twice, one week apart, at the end of each period. Twenty-four hour urinary concentration of 4-O-methylgallic acid (4OMGA), assessed once at the end of each period, was used as a marker of black tea polyphenol intake. RESULTS: The 24 h urinary excretion of 4OMGA was increased during regular ingestion of black tea in comparison to hot water (P<0.0001). Black tea resulted in lower soluble P-selectin (P=0.01) in comparison to hot water, but did not influence other adhesion molecules. Soluble P-selectin was significantly correlated with mean collagen-stimulated platelet aggregation at baseline (r=0.61, P=0.003), and during regular ingestion of hot water (r=0.70, P<0.0001) and black tea (r=0.51, P=0.01). However, platelet aggregation was not different between the black tea and hot water periods for collagen- or ADP-stimulated aggregation at any dose. Coagulation and fibrinolytic factors were also not different between periods. CONCLUSIONS: The effect of black tea on soluble P-selectin provides a potential mechanism for cardiovascular benefits of regular ingestion of tea. SPONSORSHIP: This study was supported by grants from the Tea Trade Health Research Association and the National Heart Foundation of Australia.

Adult↗

PubMed2001

Recent developments concerning diet and hypertension.

1. Recent data from randomized controlled dietary trials have shown blood pressure-lowering effects of foodstuffs and dietary patterns to be of practical importance for both individual and population blood pressure control. 2. The salient studies include Dietary Approaches to Stop Hypertension (DASH) trials, on complex dietary patterns and of additive effects of salt restriction, Trial of Nonpharmacologic Interventions in the Elderly (TONE), on weight control and sodium restriction as substitutes for drug therapy, and two Australian trials showing additive effects of dietary fish and weight control and of dietary protein and fibre in treated hypertensives. 3. Regular coffee drinking raised blood pressure in older hypertensives, whereas potential antihypertensive effects of dietary anti-oxidants require further scrutiny.

Animals↗

PubMed2001

Alcohol and endothelial function: a brief review.

1. In spite of the dose-related effects of alcohol consumption to increase blood pressure, regular light to moderate alcohol intake appears to confer protection against both coronary artery disease and ischaemic stroke. In contrast, heavy alcohol consumption increases the risk of coronary artery disease and the risk of both haemorrhagic and ischaemic stroke. 2. Effects of alcohol consumption on endothelial cell function may be relevant to these disparate effects on cardiovascular outcomes. In in vitro animal studies, low doses of alcohol have been demonstrated to increase release of nitric oxide and augment endothelium-mediated vasodilatation, whereas higher doses impair endothelium-dependent relaxation responses. In contrast, chronic administration of alcohol to rats has generally been associated with tolerance to the acute inhibitory effects of alcohol on endothelium-mediated vasodilatation and may even result in augmentation of such responses. 3. The few human studies to date that have examined the effects of alcohol on endothelial function have focused on postischaemic flow-mediated dilation of the brachial artery (FMD). Although blunted FMD responses have been reported in alcoholic subjects, acute administration of alcohol or short-term interventions to reduce alcohol intake have had no effect to either improve or impair FMD. 4. Further studies in humans assessing acute and longer term dose-related effects of alcohol on endothelial function in both conduit and resistance vessels will be necessary if the relevance of the findings from in vitro and in vivo animal studies are to be understood in the context of the complex interrelationships of alcohol with cardiovascular disease.

Alcohol Drinking↗

PubMed2001

Non pharmacologic therapy and lifestyle factors in hypertension.

Lifestyle factors are now recognised to be key determinants of both the rise in blood pressure with ageing and the cardiovascular disease associated with essential hypertension. This paper summarises recent evidence for independent or additive effects of different aspects of diet and behavioural factors on blood pressure levels and some related cardiovascular risk factors. The influence of single nutrients, fats, fibre, protein, antioxidants, caffeine, complex dietary patterns, physical activity, alcohol and smoking will be considered against a background of obesity and psychological factors contributing to blood pressure elevation.

Blood Pressure↗

PubMed2001

Long-term effects of exercise on blood pressure and lipids in healthy women aged 40-65 years: The Sedentary Women Exercise Adherence Trial (SWEAT).

OBJECTIVES: To evaluate the long-term effects of regular moderate or vigorous intensity exercise on blood pressure and blood lipids in previously sedentary older women. DESIGN: Subjects were randomly assigned to either a supervised centre-based (CB) or a minimally supervised home-based (HB) exercise program, initially for 6 months. Within each program, subjects were further randomized to exercise either at moderate (40-55% heart rate reserve, HRres) or vigorous intensity (65-80% HRres). After 6 months, all groups continued a HB moderate or vigorous exercise program for another 12 months. METHODS: Healthy, sedentary women (aged 40-65 years) (n = 126) were recruited from the community. Subjects exercised three times per week for 30 min. They were evaluated at baseline, 6, 12 and 18 months. RESULTS: There was a significant fall of 2.81 mmHg in systolic blood pressure (P = 0.049) and 2.70 mmHg in diastolic blood pressure (P = 0.004) after correction for age and baseline values with moderate exercise, but not with vigorous-intensity exercise. When this analysis was repeated with the change in body mass included, the results were unchanged. After correction for potential confounding factors, there was a significant fall in total cholesterol and low density lipoprotein cholesterol with vigorous but not moderate exercise at 6 months (P < 0.05) but not at 18 months. CONCLUSIONS: In this largely normotensive population of older women, a moderate, but not vigorous exercise program, achieved sustained falls in resting systolic and diastolic blood pressure over 18 months. The study demonstrates that, in older women, moderate intensity exercise is well accepted, sustainable long-term and has the health benefit of reduced blood pressure.

Adult↗

PubMed2001

Improved analysis of brachial artery ultrasound using a novel edge-detection software system.

Brachial artery ultrasound is commonly employed for noninvasive assessment of endothelial function. However, analysis is observer dependent and susceptible to errors. We describe studies on a computerized edge-detection and wall-tracking software program to allow more accurate and reproducible measurement. In study 1, three purpose-built Perspex phantom arteries, 3.00, 4.00, and 6.00 mm in diameter, were measured with the software. There was a mean bias of 11 microm (P < 0.001 at each level) between known and measured values; the mean resolving power of the software was estimated as 8.3 microm. In study 2, the mean intraobserver coefficient of variation of repeated measures of flow-mediated dilation (FMD) using the software (6.7%) was significantly lower than that for traditional manual measurements using the intima-lumen interfaces (24.8%, P < 0.05) and intima-media interfaces (32.5%, P < 0.05). In study 3, 24 healthy volunteers underwent repeat testing twice within 1 wk; the coefficients of variation for between-visit reproducibility of FMD and response to glyceryl trinitrate using the software were 14.7 and 17.6%, respectively. Assuming 80% power and an alpha of 0.05, eight subjects with matched controls would be required, in a parallel designed study, to detect an absolute 2.5% change in FMD. In summary, we have developed a semiautomated computerized vascular ultrasound analysis system that will improve the power of clinical intervention studies to detect small changes in arterial diameter.

Analysis of Variance↗

PubMed2001

Dietary protein and soluble fiber reduce ambulatory blood pressure in treated hypertensives.

In population studies, higher blood pressure has been associated with lower intake of protein and, possibly, lower fiber consumption. In the present randomized controlled trial, we sought to determine whether dietary protein and fiber had additive effects on blood pressure reduction in hypertensives. Treated hypertensive patients changed for 4 weeks (familiarization) to a diet low in protein (12.5% energy) and fiber (15 g/d). Patients (n=41) were then randomized to 1 of 4 groups in an 8-week factorial study of parallel design in which they continued the low-protein, low-fiber diet alone or had supplements of soy protein to increase protein intake to 25% energy, of psyllium to provide an additional 12 g soluble fiber/d, or of both protein and fiber. The 24-hour ambulatory blood pressure was compared from the end of familiarization to the end of intervention. In the 36 subjects who provided complete data, protein and fiber had significant additive effects to lower 24-hour and awake systolic blood pressure. Relative to control subjects, the net reduction in 24-hour systolic blood pressure was 5.9 mm Hg with fiber and with protein. Findings were independent of age, gender, and change in weight, alcohol intake, or urinary sodium and potassium. Relative to reduced fiber and protein intake, dietary protein and soluble fiber supplements lower blood pressure additively in hypertensives. These findings have important implications for the prevention and management of hypertension, particularly in populations in which high blood pressure is prevalent in association with diets low in protein, fiber, or both.

Blood Pressure↗

PubMed2000

Differential effects of eicosapentaenoic acid and docosahexaenoic acid on vascular reactivity of the forearm microcirculation in hyperlipidemic, overweight men.

BACKGROUND: Recent evidence supports differential effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the 2 major omega3 fatty acids of marine origin, on blood pressure in humans and vascular reactivity in adult spontaneously hypertensive rats. We investigated possible differences in the effects of purified EPA or DHA on forearm vascular reactivity in overweight hyperlipidemic men that might contribute to the blood pressure-lowering effects of fish oils. METHODS AND RESULTS: With a double-blind, placebo-controlled trial of parallel design, 59 overweight, mildly hyperlipidemic men were randomized to receive 4 g/d purified EPA, DHA, or olive oil (placebo) capsules while continuing their usual diets for 6 weeks. Forearm blood flow (FBF) was measured with venous occlusion, strain-gauge plethysmography during the sequential intra-arterial administration of acetylcholine (7.5, 15, and 30 microg/min), sodium nitroprusside (1.5, 3, and 10 microg/min), norepinephrine (10, 20, and 40 ng/min), a single-dose infusion of N:(G)-monomethyl-L-arginine (L-NMMA) (1 mg/min), and coinfusion of acetylcholine (7.5, 15, and 30 microg/min) and L-NMMA. Forty of the 56 subjects who completed the study underwent FBF measurements. Plasma phospholipid EPA levels increased significantly (P:<0.0001) after supplementation with EPA, and DHA composition increased with DHA supplementation (P:<0.0001). Relative to placebo, DHA, but not EPA, supplementation significantly improved FBF in response to acetylcholine infusion (P:=0.040) and coinfusion of acetylcholine with L-NMMA (P:=0.040). Infusion of L-NMMA alone showed no group differences. DHA significantly enhanced dilatory responses to sodium nitroprusside (P:<0.0001) and attenuated constrictor responses to norepinephrine (P:=0.017). CONCLUSIONS: Relative to placebo, DHA, but not EPA, enhances vasodilator mechanisms and attenuates constrictor responses in the forearm microcirculation. Improvements in endothelium-independent mechanisms appear to be predominant and may contribute to the selective blood pressure-lowering effect observed with DHA compared with EPA in humans.

Acetylcholine↗

PubMed2000

Gallic acid metabolites are markers of black tea intake in humans.

Gallic acid is one of the main phenolic components of black tea. The objective of this study was to identify urinary gallic acid metabolites with potential for use as markers of black tea intake. In an initial study, nine compounds, assessed by using gas chromatography-mass spectrometry, were found to increase in concentration in urine after 3 cups of black tea over 3 h. A subsequent study employed a controlled crossover design in which 10 subjects consumed 5 cups per day of black tea or water for 4 weeks in random order. Twenty-four hour urine samples were collected at the end of each period. Of the 9 candidate compounds identified in the initial study, only 3 were present at higher concentrations in urine of all 10 subjects during tea-drinking in comparison to water-drinking periods. These compounds were identified as 4-O-methylgallic acid, 3-O-methylgallic acid, and 3, 4-O-dimethylgallic acid, all methyl ether derivatives of gallic acid. It is suggested that these compounds have the potential to be used as markers of black tea intake.

Biotransformation↗