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1.
J Nutr Health Aging ; 27(1): 38-45, 2023.
Article in English | MEDLINE | ID: mdl-36651485

ABSTRACT

BACKGROUND: In recent years, a potential beneficial role of Vitamin K in neuromuscular function has been recognised. However, the optimal dietary intake of Vitamin K to support muscle function in the context of falls prevention remains unknown. OBJECTIVE: To examine the relationship of dietary Vitamin K1 and K2 with muscle function and long-term injurious fall-related hospitalisations in older women. DESIGN: Cohort study. PARTICIPANTS: 1347 community-dwelling older Australian women ≥70 years. MEASUREMENTS: A new Australian Vitamin K nutrient database, supplemented with published data, was used to calculate Vitamin K1 and K2 intake from a validated food frequency questionnaire at baseline (1998). Muscle function (grip strength and timed-up-and-go; TUG) as well plasma Vitamin D status (25OHD) were also assessed at baseline. Fall-related hospitalisations over 14.5 years were obtained from linked health records. Multivariable-adjusted logistic regression and Cox-proportional hazard models were used to analyse the data. RESULTS: Over 14.5 years of follow-up (14,774 person-years), 535 (39.7%) women experienced a fall-related hospitalisation. Compared to women with the lowest Vitamin K1 intake (Quartile 1, median 49 µg/d), those with the highest intake (Quartile 4, median 120 µg/d) had 29% lower odds (OR 0.71 95%CI 0.52-0.97) for slow TUG performance (>10.2 s), and 26% lower relative hazards of a fall-related hospitalisation (HR 0.74 95%CI 0.59-0.93) after multivariable adjustment. These associations were non-linear and plateaued at moderate intakes of ~70-100 µg/d. There was no relation to grip strength. Vitamin K2 intakes were not associated with muscle function or falls. CONCLUSION: A higher habitual Vitamin K1 intake was associated with better physical function and lower long-term injurious falls risk in community-dwelling older women. In the context of musculoskeletal health, Vitamin K1 found abundantly in green leafy vegetables should be promoted.


Subject(s)
Independent Living , Vitamin K 1 , Humans , Female , Aged , Male , Cohort Studies , Australia , Vitamin K
2.
Osteoporos Int ; 30(10): 2065-2072, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31342138

ABSTRACT

One year of calcium supplementation in older women led to modest reductions in total osteocalcin and undercarboxylated osteocalcin (ucOC), with no changes in muscle or fat mass, or glycated haemoglobin. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control. INTRODUCTION: Total osteocalcin (TOC) is a marker of bone turnover, while its undercarboxylated form has beneficial effects on glucose metabolism in mice. This post hoc analysis of a randomised double-blind, placebo-controlled trial examined whether 1 year of calcium supplementation affected circulating TOC, undercarboxylated osteocalcin (ucOC) or glycated haemoglobin (HbA1c) in 1368 older community-dwelling women (mean age 75.2 ± 2.7 years). METHODS: Women enrolled in the Calcium Intake Fracture Outcome Study trial (1998-2003) were supplemented with 1.2 g/d of elemental calcium (in the form of calcium carbonate) or placebo. Circulating TOC, ucOC and HbA1c was measured at 1 year (1999). RESULTS: After 1 year of calcium supplementation, TOC and ucOC levels were 17% and 22% lower compared with placebo (mean 22.7 ± 9.1 vs. 27.3 ± 10.9 µg/L and 11.1 ± 4.9 vs. 13.0 ± 5.7 µg/L, both P < 0.001). Carboxylated osteocalcin/ucOC was 6% lower after calcium supplementation (P < 0.05). Despite this, no differences in HbA1c were observed (calcium, 5.2 ± 0.6 vs. placebo, 5.3 ± 0.8%; P = 0.08). Calcium supplementation did not affect BMI, whole body lean or fat mass. In exploratory analyses, total calcium (dietary and supplemental) was inversely related to TOC and ucOC, indicating calcium intake is an important dietary determinant of osteocalcin levels. CONCLUSION: One year of calcium supplementation in older women led to modest reductions in TOC and ucOC, with no changes in muscle or fat mass, or HbA1c. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control.


Subject(s)
Calcium/pharmacology , Dietary Supplements , Glycated Hemoglobin/metabolism , Osteocalcin/blood , Adipose Tissue/drug effects , Aged , Biomarkers/blood , Body Composition/drug effects , Body Mass Index , Calcium/administration & dosage , Calcium, Dietary/pharmacology , Double-Blind Method , Drug Administration Schedule , Female , Humans
3.
Free Radic Biol Med ; 99: 189-198, 2016 10.
Article in English | MEDLINE | ID: mdl-27519268

ABSTRACT

BACKGROUND: Nitric oxide (NO) is an important vascular signalling molecule. NO is synthesised endogenously by endothelial nitric oxide synthase (eNOS). An alternate pathway is exogenous dietary nitrate, which can be converted to nitrite and then stored or further converted to NO and used immediately. Atherosclerosis is associated with endothelial dysfunction and subsequent lesion formation. This is thought to arise due to a reduction in the bioavailability and/or bioactivity of endogenous NO. AIM: To determine if dietary nitrate can protect against endothelial dysfunction and lesion formation in the ApoE-/- mouse fed a high fat diet (HFD). METHODS AND RESULTS: ApoE-/- fed a HFD were randomized to receive (i) high nitrate (10mmol/kg/day, n=12), (ii) moderate nitrate (1mmol/kg/day, n=8), (iii) low nitrate (0.1mmol/kg/day, n=8), or (iv) sodium chloride supplemented drinking water (control, n=10) for 10 weeks. A group of C57BL6 mice (n=6) received regular water and served as a healthy reference group. At 10 weeks, ACh-induced vessel relaxation was significantly impaired in ApoE-/- mice versus C57BL6. Mice supplemented with low or moderate nitrate showed significant improvements in ACh-induced vessel relaxation compared to ApoE-/- mice given the high nitrate or sodium chloride. Plaque collagen expression was increased and lipid deposition reduced following supplementation with low or moderate nitrate compared to sodium chloride, reflecting increased plaque stability with nitrate supplementation. Plasma nitrate and nitrite levels were significantly increased in all three groups fed the nitrate-supplemented water. CONCLUSION: Low and moderate dose nitrate significantly improved endothelial function and atherosclerotic plaque composition in ApoE-/- mice fed a HFD.


Subject(s)
Apolipoproteins E/genetics , Atherosclerosis/diet therapy , Dietary Supplements , Nitrates/administration & dosage , Nitric Oxide Synthase Type III/genetics , Nitric Oxide/metabolism , Plaque, Atherosclerotic/diet therapy , Acetylcholine/pharmacology , Animals , Aorta/drug effects , Aorta/metabolism , Aorta/pathology , Apolipoproteins E/deficiency , Atherosclerosis/etiology , Atherosclerosis/genetics , Atherosclerosis/pathology , Collagen/genetics , Collagen/metabolism , Diet, High-Fat/adverse effects , Endothelium, Vascular/drug effects , Endothelium, Vascular/metabolism , Endothelium, Vascular/pathology , Gene Expression , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Nitrates/blood , Nitric Oxide Synthase Type III/metabolism , Oxidative Stress , Plaque, Atherosclerotic/etiology , Plaque, Atherosclerotic/genetics , Plaque, Atherosclerotic/pathology , Tissue Culture Techniques , Vasodilation/drug effects
4.
Arch Biochem Biophys ; 559: 46-52, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-24583266

ABSTRACT

We have investigated the effects of the major polyphenol in coffee, chlorogenic acid (CGA), on obesity, glucose intolerance, insulin resistance, systemic oxidative stress and endothelial dysfunction in a mouse model of the metabolic syndrome. Thirty C57BL6 mice were randomly divided into (n=10/group) (i) normal diet (ND), (ii) high fat diet (HFD), or (iii) high fat diet supplemented with 0.5% w/w green coffee bean extract (GCE) rich in chlorogenic acid (HFD+GCE). The high fat diet consisted of 28% fat and all animals were maintained on their diets for 12 weeks. The mice fed a HFD and HFD+GCE displayed symptoms of the metabolic syndrome compared to their normal fed counterparts, although no endothelial dysfunction was detected in the abdominal aortas after 12 weeks. GCE did not attenuate HFD-induced obesity, glucose intolerance, insulin resistance or systemic oxidative stress. Furthermore, GCE did not protect against ex vivo oxidant (hypochlorous acid)-induced endothelial dysfunction.


Subject(s)
Coffee/chemistry , Diet, High-Fat/adverse effects , Endothelium, Vascular/drug effects , Endothelium, Vascular/pathology , Metabolic Syndrome/drug therapy , Metabolic Syndrome/pathology , Polyphenols/pharmacology , Animals , Aorta, Abdominal/drug effects , Aorta, Abdominal/physiopathology , Body Weight/drug effects , Endothelium, Vascular/metabolism , Glucose Tolerance Test , Insulin Resistance , Male , Metabolic Syndrome/etiology , Metabolic Syndrome/metabolism , Mice , Mice, Inbred C57BL , Oxidative Stress/drug effects , Polyphenols/isolation & purification , Polyphenols/therapeutic use , Vasodilation/drug effects
5.
Eur J Clin Nutr ; 68(4): 447-52, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24569536

ABSTRACT

BACKGROUND/OBJECTIVES: Evidence from animal and in vitro models suggest a role of probiotic bacteria in improving glycaemic control and delaying the onset of type 2 diabetes. However, the evidence from controlled trials in humans is limited. The objective was to determine if the probiotic bacteria L. acidophilus La5 and B. animalis subsp lactis Bb12, supplemented in a whole food (yoghurt) or isolated (capsules) form, can improve biomarkers of glycaemic control. SUBJECTS/METHODS: Following a 3-week washout period, 156 overweight men and women over 55 years (mean age: 67 ± 8 years; mean body mass index (31 ± 4 kg/m(2)) were randomized to a 6-week double-blinded parallel study. The four intervention groups were: (A) probiotic yoghurt plus probiotic capsules; (B) probiotic yoghurt plus placebo capsules; (C) control milk plus probiotic capsules; and (D) control milk plus placebo capsules. Outcome measurements, including fasting glucose, insulin, glycated haemoglobin and Homoeostasis Model Assessment of Insulin Resistance (HOMA-IR), were performed at baseline and week 6. RESULTS: Relative to the milk-control group, probiotic yoghurt resulted in a significantly higher HOMA-IR (0.32 ± 0.15, P=0.038), but did not have a significant effect on the other three measures of glycaemic control (P>0.05). Relative to placebo capsules, probiotic capsules resulted in a significantly higher fasting glucose (0.15 ± 0.07 mmol/l, P=0.037), with no significant effect on the other three measures of glycaemic control (P>0.05). Further analyses did not identify other variables as contributing to these adverse findings. CONCLUSIONS: Data from this study does not support the hypothesis that L. acidophilus La5 and B. animalis subsp lactis Bb12, either in isolated form or as part of a whole food, benefit short-term glycaemic control. Indeed, there is weak data for an adverse effect of these strains on glucose homoeostasis.


Subject(s)
Diabetes Mellitus, Type 2/therapy , Overweight/blood , Probiotics/administration & dosage , Aged , Bacillus , Biomarkers/blood , Blood Glucose/metabolism , Body Mass Index , Diabetes Mellitus, Type 2/blood , Dietary Supplements , Double-Blind Method , Female , Hemoglobins/metabolism , Humans , Insulin/blood , Insulin Resistance , Lactobacillus acidophilus , Male , Middle Aged , Patient Compliance , Yogurt/microbiology
6.
Nutr Metab Cardiovasc Dis ; 19(11): 774-80, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19346113

ABSTRACT

BACKGROUND AND AIMS: Pre-clinical studies suggest that sesame and its lignans induce beneficial changes in risk factors related to cardiovascular disease and increase the bioavailability of mammalian lignans. However, only very few intervention trials have investigated the potential bioactivities of sesame in humans. We aimed to investigate the effects of sesame supplementation in humans on blood lipids, blood pressure, systemic oxidative stress, inflammatory biomarkers and mammalian lignan metabolism. METHODS AND RESULTS: We conducted a randomized, placebo-controlled cross-over intervention trial at a university research centre. Overweight or obese men and women (n=33) consumed 25g/d of sesame ( approximately 50mg/d of sesame lignan) and an iso-caloric placebo matched for macronutrient composition for 5 wks each. Each intervention period was preceded by a 4-wk washout period. Blood lipid profiles, day time ambulatory blood pressure, oxidative stress and inflammatory biomarkers and urinary mammalian lignans were measured before and after each intervention. Results are presented as the effect of sesame supplementation relative to placebo. Urinary excretion of the mammalian lignans, enterolactone and enterodiol, increased by approximately 8-fold (P<0.001). Blood lipids and blood pressure were not altered. In addition, markers of systemic inflammation (C-reactive protein, interleukin-6, tumor necrosis factor-alpha) and lipid peroxidation (F(2)-isoprostanes) were not affected. CONCLUSION: Supplementation with 25g/d of sesame can significantly increase the exposure to mammalian lignans. However, this did not cause any improvement in markers of cardiovascular disease risk in overweight or obese men and women.


Subject(s)
Cardiovascular Diseases/prevention & control , Dietary Supplements , Lignans/administration & dosage , Obesity/drug therapy , Phytotherapy , Sesamum , Biomarkers/blood , Blood Pressure/drug effects , Cardiovascular Diseases/blood , Cardiovascular Diseases/etiology , Cardiovascular Diseases/physiopathology , Cross-Over Studies , Female , Humans , Inflammation Mediators/blood , Lignans/urine , Lipid Peroxidation/drug effects , Lipids/blood , Male , Middle Aged , Obesity/blood , Obesity/complications , Obesity/physiopathology , Oxidative Stress/drug effects , Risk Factors , Seeds , Time Factors
7.
Clin Exp Pharmacol Physiol ; 33(9): 838-41, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16922817

ABSTRACT

1. The consumption of tea worldwide is second only to water. Thus, any physiological effects of tea could have a significant impact on population health. 2. Tea is the major contributor to total flavonoid intake in many populations. Flavonoids in tea have been shown to have a range of activities and effects that could contribute to improved health. Tea intake and the intake of flavonoids found in tea have been associated with reduced risk of cardiovascular disease in several cross-sectional and prospective population studies. A variety of possible mechanisms have been investigated. The focus of the present review is on the mounting evidence that tea flavonoids can improve endothelial function and lower blood pressure. 3. In vitro studies using isolated vessels have shown that tea flavonoids possess vasodilator activity. Results of human intervention trials have shown that increased flavonoid intake from tea, as well as other dietary sources, can improve endothelial function. Emerging data also suggest that the degree of benefit may be related to flavonoid metabolism. 4. The effects of tea flavonoids on blood pressure are less consistent. Results of animal studies and population studies are consistent with a blood pressure-lowering effect of tea. However, short-term intervention trials, mainly in normotensive individuals, have not demonstrated any blood pressure reduction with tea. 5. Overall, the available data suggest that the effects of tea flavonoids on endothelial function and, perhaps, blood pressure may be responsible, at least in part, for any benefits of drinking tea on the risk of cardiovascular disease.


Subject(s)
Blood Pressure/drug effects , Endothelium, Vascular/drug effects , Flavonoids/pharmacology , Tea/chemistry , Animals , Cardiovascular Diseases/prevention & control , Humans , Vasodilation/drug effects
8.
Eur J Clin Nutr ; 56(11): 1137-42, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12428181

ABSTRACT

OBJECTIVE: Our objective was to assess effects of dietary supplementation with coenzyme Q10 (CoQ) on blood pressure and glycaemic control in subjects with type 2 diabetes, and to consider oxidative stress as a potential mechanism for any effects. SUBJECTS AND DESIGN: Seventy-four subjects with uncomplicated type 2 diabetes and dyslipidaemia were involved in a randomised double blind placebo-controlled 2x2 factorial intervention. SETTING: The study was performed at the University of Western Australia, Department of Medicine at Royal Perth Hospital, Australia. INTERVENTIONS: Subjects were randomly assigned to receive an oral dose of 100 mg CoQ twice daily (200 mg/day), 200 mg fenofibrate each morning, both or neither for 12 weeks. MAIN OUTCOME MEASURES: We report an analysis and discussion of the effects of CoQ on blood pressure, on long-term glycaemic control measured by glycated haemoglobin (HbA(1c)), and on oxidative stress assessed by measurement of plasma F2-isoprostanes. RESULTS: Fenofibrate did not alter blood pressure, HbA(1c), or plasma F2-isoprostanes. There was a 3-fold increase in plasma CoQ concentration (3.4+/-0.3 micro mol/l, P<0.001) as a result of CoQ supplementation. The main effect of CoQ was to significantly decrease systolic (-6.1+/-2.6 mmHg, P=0.021) and diastolic (-2.9+/-1.4 mmHg, P=0.048) blood pressure and HbA(1c) (-0.37+/-0.17%, P=0.032). Plasma F2-isoprostane concentrations were not altered by CoQ (0.14+/-0.15 nmol/l, P=0.345). CONCLUSIONS: These results show that CoQ supplementation may improve blood pressure and long-term glycaemic control in subjects with type 2 diabetes, but these improvements were not associated with reduced oxidative stress, as assessed by F2-isoprostanes. SPONSORSHIP: This study was supported by a grant from the NH&MRC, Australia.


Subject(s)
Antioxidants/pharmacology , Blood Glucose/drug effects , Blood Pressure/drug effects , Diabetes Mellitus, Type 2/blood , Ubiquinone/analogs & derivatives , Ubiquinone/pharmacology , Antioxidants/therapeutic use , Blood Glucose/metabolism , Coenzymes , Diabetes Mellitus, Type 2/drug therapy , Dietary Supplements , Double-Blind Method , F2-Isoprostanes/blood , Female , Fenofibrate/pharmacology , Glycated Hemoglobin/analysis , Glycated Hemoglobin/drug effects , Humans , Hyperlipidemias/blood , Hyperlipidemias/drug therapy , Hypolipidemic Agents/pharmacology , Male , Middle Aged , Oxidative Stress/drug effects , Ubiquinone/blood , Ubiquinone/therapeutic use
9.
Eur J Clin Nutr ; 55(10): 881-6, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11593350

ABSTRACT

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.


Subject(s)
Cell Adhesion Molecules/blood , Gallic Acid/analogs & derivatives , Gallic Acid/urine , Homeostasis/physiology , P-Selectin/blood , Tea , Adult , Aged , Biomarkers , Cross-Over Studies , Female , Homeostasis/drug effects , Humans , Male , Middle Aged , P-Selectin/drug effects , Platelet Aggregation/physiology
10.
Hypertension ; 38(4): 821-6, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11641293

ABSTRACT

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.


Subject(s)
Blood Pressure/drug effects , Dietary Fiber/administration & dosage , Dietary Proteins/administration & dosage , Hypertension/therapy , Blood Pressure Monitoring, Ambulatory , Body Weight/drug effects , Diastole , Female , Heart Rate/drug effects , Humans , Hypertension/physiopathology , Male , Middle Aged , Solubility , Systole , Treatment Outcome , Urea/urine
11.
Clin Exp Pharmacol Physiol ; 28(12): 1078-82, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11903320

ABSTRACT

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.


Subject(s)
Diet , Hypertension/diet therapy , Animals , Antioxidants/administration & dosage , Antioxidants/pharmacology , Blood Pressure/drug effects , Body Weight/drug effects , Caffeine/adverse effects , Coffee/adverse effects , Dietary Fiber/administration & dosage , Dietary Fiber/pharmacology , Dietary Proteins/administration & dosage , Dietary Proteins/pharmacology , Fishes , Humans , Hypertension/complications , Hypertension/physiopathology , Obesity/complications , Obesity/diet therapy , Obesity/physiopathology , Randomized Controlled Trials as Topic , Sodium/adverse effects , Vitamins/pharmacology , Vitamins/therapeutic use
12.
J Agric Food Chem ; 48(6): 2276-80, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10888536

ABSTRACT

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.


Subject(s)
Gallic Acid/urine , Tea , Biotransformation , Feeding Behavior , Female , Gallic Acid/analogs & derivatives , Humans , Male , Tea/metabolism
13.
Am J Clin Nutr ; 71(5): 1103-7, 2000 May.
Article in English | MEDLINE | ID: mdl-10799371

ABSTRACT

BACKGROUND: Tea has been associated with a reduced risk of cardiovascular disease. One proposed mechanism of this risk reduction involves inhibition of lipoprotein oxidation in vivo by antioxidant polyphenolic compounds derived from tea. However, controlled interventions uniformly failed to show that ingestion of tea can inhibit LDL oxidation ex vivo. The absence of effects in previous studies may be due to the isolation of LDL particles from polyphenolic compounds that are present in the aqueous phase of serum. OBJECTIVE: The objective of this study was to examine the acute effects of ingestion of black and green tea on ex vivo Cu(2+)-induced lipoprotein oxidation without prior isolation of lipoproteins from serum. DESIGN: The acute effects of 4 hot drinks-green tea and black tea (each at a dose equivalent to 4 standard cups), water matched to the teas for caffeine content, and water-were assessed in 20 healthy men by using a Latin-square design. The lag time to lipoprotein diene formation, slope of the propagation phase of the oxidation curve, and area under the oxidation curve were calculated. Urinary concentrations of 4-O-methylgallic acid were used as a marker of uptake and metabolism of polyphenolic compounds from tea. RESULTS: Significant increases in urinary 4-O-methylgallic acid for black and green tea (P < 0. 0001) were observed. Caffeine did not significantly influence lipoprotein oxidation. Compared with the water control, there was a greater lag time for black tea (5.4 +/- 2.9 min; P = 0.05) that was of borderline significance and a similar trend for green tea (4.4 +/- 2.8 min; P = 0.17). Slope and area under the oxidation curve were not altered. CONCLUSION: Black tea has a mild acute effect on ex vivo lipoprotein oxidation in human serum. 2000;71:-7.


Subject(s)
Flavonoids , Lipid Peroxides/biosynthesis , Lipoproteins/metabolism , Tea/physiology , Adult , Aged , Antioxidants/analysis , Area Under Curve , Caffeine/metabolism , Chromatography, Gas , Copper Sulfate/chemistry , Fluoresceins/chemistry , Gallic Acid/analogs & derivatives , Gallic Acid/urine , Humans , Linear Models , Lipid Peroxides/blood , Male , Middle Aged , Oxidation-Reduction , Phenols/analysis , Polymers/analysis , Polyphenols , Tea/metabolism
14.
J Hypertens ; 17(4): 457-63, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10404946

ABSTRACT

BACKGROUND: The flavonoid components of tea have been associated in epidemiological studies with a decreased risk of cardiovascular disease. Flavonoids have been shown to have antioxidant and vasodilator effects in vitro; we therefore postulated that drinking green or black tea attenuates the well-characterized acute pressor response to caffeine and lowers blood pressure during regular consumption. OBJECTIVE: To determine whether green and black tea can attenuate the transient pressor effect of caffeine, or lower blood pressure during regular consumption. METHODS: In the first study, the acute effects of four hot drinks - green tea and black tea (at a dose equivalent to four standard cups), water matched to the teas for caffeine content ('caffeine') and water - were assessed in 20 normotensive men using a Latin-Square designed study. Clinic blood pressure was measured before and 30 and 60 min after each drink had been ingested. In the second study, the effects on blood pressure of regular green and black tea ingestion were examined in 13 subjects with high-normal systolic blood pressure and mild systolic hypertension (systolic blood pressure in the range 130-150 mmHg) using a three-period crossover study. Five cups per day of green tea, black tea and caffeine (in hot water and matched to the teas) were consumed for 7 days each, in random order. Twenty-four hour ambulatory blood pressure was measured at the end of each seven-day intervention. Results are presented as means and 95% confidence intervals (CI). RESULTS: An acute pressor response to caffeine was observed. Relative to caffeine, there were further acute increases in systolic and diastolic blood pressure at 30 min among those drinking green tea [5.5 mmHg (95%CI -1.4 to 12.4) and 3.1 mmHg (95%CI -0.1 to 6.3), respectively] and black tea [10.7 mmHg (95%CI 4.0 to 17.4) and 5.1 mmHg (95%CI 1.8 to 8.4), respectively]. The changes in blood pressure at 60 min were not significant The effect on 24-h ambulatory systolic and diastolic blood pressure of regular drinking of green tea [increases of 1.7 mmHg (95%CI -1.6 to 5.0) and 0.9 mmHg (95%CI -1.3 to 3.1), respectively] or black tea [increase of 0.7 mmHg (95%CI -2.6 to 4.0) and decrease of 0.7 mmHg (95%CI -2.9 to 1.5), respectively] was not significant relative to caffeine. CONCLUSIONS: Contrary to our initial hypothesis, tea ingestion caused larger acute increases in blood pressure than caffeine alone. However, any acute effects of tea on blood pressure did not translate into significant alterations in ambulatory blood pressure during regular tea consumption.


Subject(s)
Blood Pressure/drug effects , Tea/chemistry , Adult , Aged , Caffeine/pharmacology , Cross-Over Studies , Female , Flavonoids/pharmacology , Humans , Male , Middle Aged , Plant Extracts/pharmacology
15.
Am J Hypertens ; 12(1 Pt 1): 47-53, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10075384

ABSTRACT

Vegetarian diets lower blood pressure (BP), but attempts to identify dietary components responsible have been unsuccessful. Isoflavonoids are commonly consumed as part of vegetarian diets. The objective of this study was to assess the effect of isoflavonoid supplementation on BP. Fifty-nine subjects with high-normal range systolic BP completed a randomized, double blind, placebo-controlled trial of two-way parallel design and 8 weeks duration. One tablet containing 55 mg of isoflavonoids, including 30 mg of genistein, 16 mg of biochanin A (a genistein precursor), 1 mg of daidzein, and 8 mg of formononetin (a daidzein precursor), or one placebo tablet, was taken daily with the evening meal. Significant increases in urinary excretion of genistein (5.22 mg/day, 95% CI: 3.72, 6.72) and daidzein (2.53 mg/day, 95% CI: 1.66, 3.40) were observed in the group taking the isoflavonoid supplement. There were no significant changes in isoflavonoid excretion in the placebo group. Clinic BP was measured at two visits, and ambulatory BP monitoring was performed over one 24-h period, at baseline and postintervention. There was no significant difference between groups, after adjustment for baseline values, in postintervention clinic supine BP (systolic 1.2 mm Hg, 95% CI: -2.3, 4.7; diastolic 0.6 mm Hg, 95% CI: -1.9, 2.5), clinic erect BP (systolic 1.7 mm Hg, 95% CI: -4.0, 8.4; diastolic 0.4 mm Hg, 95% CI: -2.4, 3.2), or 24-h ambulatory BP (systolic -1.4 mm Hg, 95% CI: -4.4, 1.6; diastolic -0.8 mm Hg, 95% CI: -2.3, 0.7). Adjustment for age, gender, and weight change did not alter the result. Therefore, these results do not support the hypothesis that isoflavonoids, and genistein in particular, are major contributors to the BP lowering effect of vegetarian diets.


Subject(s)
Blood Pressure Monitoring, Ambulatory , Blood Pressure/drug effects , Genistein/pharmacology , Isoflavones/pharmacology , Adult , Aged , Calcium/urine , Diet, Vegetarian , Dietary Supplements , Double-Blind Method , Drug Combinations , Female , Follow-Up Studies , Genistein/urine , Humans , Hypertension/prevention & control , Isoflavones/urine , Male , Middle Aged , Potassium/urine , Sodium/urine
16.
J Nutr ; 128(4): 728-32, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9521635

ABSTRACT

Isoflavonoids are a class of flavonoids that are derived in the human diet mainly from soybean-based foods. The major dietary isoflavonoids, genistein and daidzein, have estrogen-like activity and are classed as phytoestrogens. Because estrogens can lower serum LDL cholesterol and raise HDL cholesterol, the objective of this study was to determine if isoflavonoids could improve serum lipids in healthy subjects. Forty-six men and 13 postmenopausal women not receiving hormone replacement therapy completed a randomized, double-blind, placebo-controlled trial of two-way parallel design and 8 wk duration. One tablet containing 55 mg of isoflavonoids (predominantly in the form of genistein) or one placebo tablet was taken daily with the evening meal. Subjects maintained their usual diet and physical activity, which were unchanged throughout the intervention. Measurement of isoflavonoids and their metabolites in 24-h urine samples provided an assessment of compliance and of isoflavonoid metabolism. Serum total, LDL, HDL and HDL subclass cholesterol, triglycerides and lipoprotein (a) were assessed at baseline and during the last week of intervention. After adjustment for baseline values, no significant differences in postintervention serum lipid and lipoprotein (a) concentrations between groups were identified. Further adjustment for age, gender and weight change did not alter the results. In addition, changes in urinary isoflavonoids were not significantly correlated with changes in serum lipids and lipoprotein (a). Therefore, this study does not support the hypothesis that isoflavonoid phytoestrogens can improve the serum lipids, at least in subjects with average serum cholesterol concentrations.


Subject(s)
Dietary Supplements , Estrogens, Non-Steroidal/pharmacology , Isoflavones/pharmacology , Lipids/blood , Adult , Aged , Body Weight , Double-Blind Method , Female , Humans , Isoflavones/urine , Lipoproteins/blood , Male , Middle Aged , Osmolar Concentration , Phytoestrogens , Plant Preparations
17.
Am J Clin Nutr ; 58(2): 228-34, 1993 Aug.
Article in English | MEDLINE | ID: mdl-8192728

ABSTRACT

The adipose tissue concentration of linoleic acid was positively associated with the degree of coronary artery disease (CAD) in a cross-sectional study of 226 patients undergoing coronary angiography. Linoleic acid concentration in adipose tissue is known to reflect the intake of this fatty acid. These results are therefore indicative of a positive relationship between linoleic acid intake and CAD. The platelet linoleic acid concentration was also positively associated with CAD. After confounding factors were allowed for, the eicosapentaenoic acid concentration in platelets was inversely associated with CAD for men, and the docosapentaenoic acid concentration in platelets was inversely associated with CAD for women; results consistent with several other studies that suggest that fish, and omega-3 fatty acids derived from fish and fish oils, can beneficially influence macrovascular disease.


Subject(s)
Coronary Disease/etiology , Linoleic Acids/adverse effects , Adipose Tissue/chemistry , Adolescent , Adult , Age Factors , Aged , Blood Platelets/chemistry , Cholesterol/blood , Coronary Angiography , Coronary Disease/epidemiology , Cross-Sectional Studies , Fatty Acids/analysis , Female , Humans , Hypertension/complications , Linoleic Acid , Linoleic Acids/administration & dosage , Linoleic Acids/analysis , Linoleic Acids/blood , Male , Middle Aged , Risk Factors , Smoking/adverse effects
18.
J Oral Rehabil ; 16(1): 71-4, 1989 Jan.
Article in English | MEDLINE | ID: mdl-2746407

ABSTRACT

Previous research has suggested a relationship between migraine pain and oral habits. The present study was designed as a replication of a prior study that found self-reported higher frequencies of certain oral habits in migraine as opposed to tension headache and non-headache groups. Three groups of subjects (common migraine, tension headache and non-headache) were given a single questionnaire in which five oral habits (i.e. teeth clenching, jaw jutting, cupping the chin in the hand, and resting the right and left side of the face on the hand) were rated on a 0 (not at all) to 10 (almost always) scale. Significant main effects were obtained for groups and oral habits in a 3 (groups) X5 (oral habits) ANOVA. Post hoc Tukey tests revealed the common migraine group reported significantly more frequent oral habits than did the tension headache group. The non-headache control group did not differ significantly from either headache group. Discussion focuses on the need for continued research in this area.


Subject(s)
Habits , Headache/physiopathology , Migraine Disorders/physiopathology , Mouth/physiology , Adult , Dental Occlusion , Female , Humans , Male , Mandible/physiology , Middle Aged , Tooth/physiology
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