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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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Subject: search.filters.subject.Cholesterol

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    Assessment of vitamin E status in patients with systemic inflammatory response syndrome: Plasma, plasma corrected for lipids or red blood cell measurements?
    (Elsevier, 2009-08-19) Vasilaki, Katerina; Leivaditi, Dimitra; Talwar, Dinesh; Kinsella, John; Duncan, Andrew; O'Reilly, Denis St J.; McMillan, Donald C.
    Background: There is some evidence that the plasma vitamin E status is perturbed as part of systemic inflammatory response and correcting this with other plasma markers may not lead to reliable results. The aim of the present study was to examine the longitudinal inter-relationships between plasma and red blood cell vitamin α-tocopherol in patients with systemic inflammatory response syndrome. Methods: α-tocopherol concentrations were measured, by HPLC, in plasma and red blood cells in normal subjects (n = 67) and in critically ill patients with systemic inflammatory response syndrome (n = 82) on admission and on follow-up. Results: Plasma α-tocopherol was significantly lower in the critically ill patients compared with the controls (all p < 0.001) with 41% of patients having concentrations below the 95% confidence interval. In contrast, when corrected for cholesterol, α-tocopherol concentrations were significantly higher in the critically ill patients compared with the control group (p < 0.001, 27% above the 95% confidence interval) and when corrected for triglycerides, α-tocopherol concentrations were significantly lower in the critically ill patients compared with the control group (p < 0.001). Red blood cell α-tocopherol corrected for haemoglobin was similar (p = 0.852) in the critically ill patients compared with control subjects. The longitudinal measurements (n = 53) gave similar results. Conclusions: These results indicate that there is a discrepancy between vitamin E measurements in plasma, in plasma corrected for lipids and in red blood cells. Although the value of correcting vitamin E concentrations by lipids is well established in population studies, the present study indicates that such correction is unreliable in the presence of systemic inflammatory response syndrome and that vitamin E status should be assessed using red blood cell α-tocopherol measurement.
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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.