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Dietetics, Nutrition and Biological Sciences

Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/23

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Author: search.filters.author.Al-Dujaili, Emad A. S.Subject: search.filters.subject.Glucocorticoids

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    Consumption of Pomegranate Juice Attenuates Exercise - Induced Oxidative Stress, Blood Pressure and Urinary Cortisol/Cortisone Ratio in Human Adults
    (E-Cronicon, 2016-08-23) Al-Dujaili, Emad A. S.; Good, Gillian; Tsang, Catherine
    Background: Oxidative stress is exacerbated in overweight and obese individuals after acute exercise compared with their nonobese counterparts. Antioxidants supplementation of the diet may be one intervention to reduce exercise-induced oxidative stress in this vulnerable population. The aim of this study was to investigate whether polyphenol-rich pomegranate juice attenuates postexercise oxidative stress and contributors to oxidative stress (glucocorticoids) and blood pressure in healthy overweight subjects. Methods: Males and females participated in a randomized placebo controlled parallel pilot-study (mean BMI: 26.7 ± 6.6 kg/m2 ). Two groups of (n = 12) participants received either pomegranate pure juice (500 mL/day containing total polyphenols of 1685 mg GAE/L) or placebo (water matched for total energy) and all participants completed two standardized 30 min treadmill tests (50% Wmax) at baseline and after one week of the intervention. Results: Exercise induced lipid peroxidation (MDA) was lower following pomegranate juice consumption compared with placebo (31.2 ± 10.6 to 26.5 ± 9.8 MDA µmole/day) after 1 week (P = 0.035). Urinary free cortisol was reduced from 179.4 ± 53.2 to 125.6 ± 43.5 nmole/24h which was significant (p = 0.042). In addition, there was a statistically significant increase in urinary free cortisone: from 112.2 ± 40.4 to 187.6 ± 90.2 nmole/24 h (p = 0.045), and a significant decrease in the urinary free cortisol/cortisone ratio (p=0.009) from 1.6 ± 1.1 to 0.67 ± 0.55 following one week of pomegranate juice intake. Pomegranate juice consumption was also found to decrease systolic blood pressure pre-exercise (136.7 ± 11.7 to 131.8 ± 8.8 mmHg (p = 0.007), and post-exercise from 158.8 ± 15.8 to 148.1 ± 12.3 mmHg (p < 0.01) and diastolic blood pressure (86.3 ± 10.6 to 82.5 ± 6.8 mmHg (p = 0.04) and 103.1 ±12.5 to 93.9 ± 11.5 mmHg (p = 0.001), pre and post exercise, respectively. Correlation results between the change in Cortisol/cortisone ratio with the effect on blood pressure showed a negative significant association post pomegranate juice intake (p = 0.028 for systolic and p = 0,008 for diastolic BP). There were no changes in lipid peroxidation or blood pressure following placebo treatment. Conclusions: These findings suggest that pomegranate juice consumption prior to an acute bout of moderate intensity exercise can alleviate blood pressure and exercise-induced stress in the overweight and obese population.
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    Post-prandial changes in salivary glucocorticoids: Effects of dietary cholesterol and associations with bile acid excretion
    (2019-02-09) Anderson, Graham W.; Kenyon, Christopher J.; Al-Dujaili, Emad A. S.
    Mechanisms to explain post-prandial increases in circulating glucocorticoids are not well understood and may involve increased adrenal secretion and/or altered steroid metabolism. We have compared salivary levels of cortisol and cortisone levels in healthy male and female volunteers fed either a low or cholesterol-rich midday meal. Urinary levels of steroids, bile acids and markers of lipid peroxidation were also measured. Males and females showed expected circadian changes in salivary steroids and postprandial peaks within 1h of feeding. After a high-cholesterol meal, postprandial cortisol increases were higher in males whereas post-prandial cortisone levels were higher in females. Urinary cortisol but not cortisone levels were higher on the day when males and females ate a high-cholesterol meal. Urinary bile acid excretion and anti-oxidant markers of lipid peroxidation, thiobarbituric acid reactive substances (TBARS), and total phenol content were not affected by dietary cholesterol but tended to be higher in males. Cross-tabulation of correlation coefficients indicated positive associations between urinary markers of peroxidation, bile acids, and cortisol:cortisone ratios. We conclude that dietary cholesterol (a substrate for steroidogenesis) does not have an acute effect on adrenal glucocorticoid synthesis and that gender but not a high-cholesterol meal may influence the interconversion of cortisol and cortisone. Longer term studies of the effects of dietary cholesterol are needed to analyze the associations between bile acids, steroid metabolism, and secretion and lipid peroxidation.
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    Intake of polyphenol-rich pomegranate pure juice influences urinary glucocorticoids, blood pressure and homeostasis model assessment of insulin resistance in human volunteers
    (2012-08) Tsang, Catherine; Smail, Nacer Foudil; Almoosawi, Suzana; Davidson, Isobel; Al-Dujaili, Emad A. S.
    Pomegranate juice (PJ; also known as pomegreat pure juice) provides a rich and varied source of polyphenolic compounds that may offer cardioprotective, anti-atherogenic and antihypertensive effects. The aim of this study was to investigate the effect of PJ consumption on glucocorticoids levels, blood pressure (BP) and insulin resistance in volunteers at high CVD risk. Subjects (twelve males and sixteen females) participated in a randomised, placebo-controlled cross-over study (BMI: 2677 (sd 336) kg/m2; mean age: 504 (sd 61) years). Volunteers were assessed at baseline, and at weeks 2 and 4 for anthropometry, BP and pulse wave velocity. Cortisol and cortisone levels in urine and saliva were determined by specific ELISA methods, and the cortisol/cortisone ratio was calculated. Fasting blood samples were obtained to assess plasma lipids, glucose, insulin and insulin resistance (homeostasis model assessment of insulin resistance). Volunteers consumed 500 ml of PJ or 500 ml of a placebo drink containing a similar amount of energy. Cortisol urinary output was reduced but not significant. However, cortisol/cortisone ratios in urine (P = 0009) and saliva (P = 0024) were significantly decreased. Systolic BP decreased from 1364 (sd 63) to 1289 (sd 51) mmHg (P = 0034), and diastolic BP from 803 (sd 429) to 755 (sd 517) mmHg (P = 0031) after 4 weeks of fruit juice consumption. Pulse wave velocity decreased from 75 (sd 086) to 744 (sd 094) m/s (P = 0035). There was also a significant reduction in fasting plasma insulin from 936 (sd 58) to 753 (sd 412) mIU/l (P = 0025) and of homeostasis model assessment of insulin resistance (from 2216 (sd 143) to 182 (sd 112), P = 0028). No significant changes were seen in the placebo arm of the study. These results suggest that PJ consumption can alleviate key cardiovascular risk factors in overweight and obese subjects that might be due to a reduction in both systolic and diastolic BP, possibly through the inhibition of 11_-hydroxysteroid dehydrogenase type 1 enzyme activity as evidenced by the reduction in the cortisol/cortisone ratio. The reduction in insulin resistance might have therapeutic benefits for patients with non-insulin-dependent diabetes, obesity and the metabolic syndrome.