Background and aims: The accumulation of fat increases the formation of lipid perox-ides, which are partly scavenged by alpha-tocopherol (a-TOH). Here, we aimed to investigate the associations... Show moreBackground and aims: The accumulation of fat increases the formation of lipid perox-ides, which are partly scavenged by alpha-tocopherol (a-TOH). Here, we aimed to investigate the associations between different measures of (abdominal) fat and levels of urinary a-TOH metab-olites in middle-aged individuals. Methods and results: In this cross-sectional analysis in the Netherlands Epidemiology of Obesity study (N Z 511, 53% women; mean [SD] age of 55 [6.1] years), serum a-TOH and a-TOH metab-olites from 24-h urine were measured as alpha-tocopheronolactone hydroquinone (a-TLHQ, oxidized) and alpha-carboxymethyl-hydroxychroman (a-CEHC, enzymatically converted) using liquid-chromatography-tandem mass spectrometry. Body mass index and total body fat were measured, and abdominal subcutaneous and visceral adipose tissue (aSAT and VAT) were as-sessed using magnetic resonance imaging. Using multivariable-adjusted linear regression ana -lyses, we analysed the associations of BMI, TBF, aSAT and VAT with levels of urinary a-TOH metabolites, adjusted for confounders. We observed no evidence for associations between body fat measures and serum a-TOH. Higher BMI and TBF were associated with lower urinary levels of TLHQ (0.95 [95%CI: 0.90, 1.00] and 0.94 [0.88, 1.01] times per SD, respectively) and with lower TLHQ relative to CEHC (0.93 [0.90, 0.98] and 0.93 [0.87, 0.98] times per SD, respectively). We observed similar associations for VAT (TLHQ: 0.94 [0.89, 0.99] times per SD), but not for aSAT. Conclusions: Opposite to our research hypothesis, higher abdominal adiposity was moderately associated with lower levels of oxidized a-TOH metabolites, which might reflect lower vitamin E antioxidative activity in individuals with higher abdominal fat instead. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Luo, J.; Mills, K.; Cessie, S. le; Noordam, R.; Heemst, D. van 2020
Among other mechanisms, oxidative stress has been postulated to play an important role in the rate of ageing. Oxidative damage contributes to the hallmarks of ageing and essential components in... Show moreAmong other mechanisms, oxidative stress has been postulated to play an important role in the rate of ageing. Oxidative damage contributes to the hallmarks of ageing and essential components in pathological pathways which are thought to drive multiple age-related diseases. Nonetheless, results from studies testing the hypothesis of oxidative stress in ageing and diseases showed controversial results. While observational studies mainly found detrimental effects of high oxidative stress levels on disease status, randomized clinical trials examining the effect of antioxidant supplementation on disease status generally showed null effects. However, re-evaluations of these counterinitiative observations are required considering the lack of reliability and specificity of traditionally used biomarkers for measuring oxidative stress. To facilitate these re-evaluations, this review summarizes the basic knowledge of oxidative stress and the present findings regarding the role of oxidative damage in ageing and age-related diseases. Meanwhile, two approaches are highlighted, namely proper participants selection, together with the development of reliable biomarkers. We propose that oxidized vitamin E metabolites may be used to accurately monitor individual functional antioxidant level, which might serve as promising key solutions for future elucidating the impact of oxidative stress on ageing and age-related diseases. Show less
