Effects of supplementation with high-selenium wheat bread on selenium, glutathione peroxidase and related enzymes in blood components of New Zealand residents

Thomson, Christine D.; Ong, Lay Khoon; Robinson, Marion F.

doi:10.1093/ajcn/41.5.1015

Cited by 61 publications

(17 citation statements)

References 39 publications

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“…21 Glutathione peroxidase protects erythrocytes from oxidative damage, and in humans, selenium supplementation has been shown to increase glutathione peroxidase activities in erythrocytes. 3,4,22 Although α-tocopherol has been shown to protect erythrocytes from oxidative damage in vitro , 23 no significant relationship was found between serum α-tocopherol concentrations and RDW in the present study. Protein carbonyls were not associated with RDW and may represent a different pathway of oxidative stress that is not affected by selenium.…”

Section: Discussioncontrasting

confidence: 66%

Serum antioxidants and inflammation predict red cell distribution width in older women: The Women's Health and Aging Study I

et al. 2010

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Background & Aims Red cell distribution width (RDW), a measure of heterogeneity in the size of circulating erythrocytes, is associated with some chronic diseases and predicts mortality. Although oxidative damage and inflammation have been theorized to affect RDW, the relationships of antioxidants and inflammation with RDW have not been well characterized. The aims were to determine whether total serum carotenoids, α-tocopherol, selenium, protein carbonyls, and interleukin-6 (IL-6) are associated with RDW and predict RDW over time. Methods RDW was measured at baseline, 12 months, and 24 months follow-up in 786 moderately to severely disabled community-dwelling women, aged ≥65 years, in the Women’s Health and Aging Study I in Baltimore, Maryland. Results Selenium was significantly associated with RDW at baseline and predicted RDW over two years’ follow-up in separate multivariate mixed effects models that adjusted for other covariates. As expected, the addition of IL-6 to the models attenuated the association of serum selenium with RDW, as low antioxidant levels are known to upregulate IL-6. Total carotenoids were associated with RDW at baseline and one year follow-up. Protein carbonyls and α-tocopherol were not significantly associated with RDW. Conclusion Serum selenium is an independent predictor of RDW and may potentially mediate effects on RDW through IL-6.

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Section: Discussioncontrasting

confidence: 66%

Serum antioxidants and inflammation predict red cell distribution width in older women: The Women's Health and Aging Study I

et al. 2010

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“…Moreover, the extent of the response depends on the initial level of activity (Brown et al, 2000). On the other hand, platelet GPx appears to be a more sensitive indicator of increasing selenium intake, showing increases in activity within 1-2 weeks of commencing supplementation (Levander et al, 1983;Thomson et al, 1985;Nève et al, 1988;Alfthan et al, 1991;Van der Torre et al, 1991;Thomson et al, 1993). This might be related to the shorter lifespan of 8-14 days of platelets, compared to 120 days for erythrocytes (Nève, 1995).…”

Section: Biochemical Tests For Nutritional Status Of Seleniummentioning

confidence: 99%

Assessment of requirements for selenium and adequacy of selenium status: a review

2004

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Objective: The intent of this review is to evaluate the scientific evidence for the assessment of adequacy of selenium status and of the requirements for selenium. From this evidence, attempts have been made to define levels of plasma selenium and dietary selenium intake, which could be used for the assessment of deficiency or adequacy of selenium status. Method: The first section briefly reviews the methods for assessment of selenium status. The second section outlines the requirements for selenium based on a number of criteria, and how these have been translated into recommended intakes of selenium. In the final section, levels of plasma selenium and dietary intake based on different criteria of adequacy have been proposed. Results and conclusion: The minimum requirement for selenium is that which prevents the deficiency disease, Keshan disease. The recommended intakes of selenium have been calculated from the requirement for optimum plasma glutathione peroxidase (GPx) activity that must, because of the hierarchy of selenoproteins, also take account of the amounts needed for normal levels of other biologically necessary selenium compounds. Whether optimal health depends upon maximization of GPx or other selenoproteins, however, has yet to be resolved, and the consequences of less-than-maximal GPx activities or mRNA levels need investigation. Intakes, higher than recommended intakes, and plasma selenium concentrations that might be protective for cancer or result in other additional health benefits have been proposed. There is an urgent need for more large-scale trials to assess any such beneficial effects and to provide further data on which to base more reliable estimates for intakes and plasma selenium levels that are protective.

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“…A possible mechanism explaining the effect of wholegrains on glutathione balance comes from in vitro evidence that flavonoids alter the expression of genes responsible for the synthesis and regulation of glutathione (Table 2) [128,129]. There is further evidence from a dietary intervention study in humans that selenium improves glutathione peroxidase activity [130]. Subjects consuming brown or wholemeal bread made from wheat containing high levels of selenium increased whole blood glutathione peroxidase levels by 10% [131].…”

Section: Metabolic Disease and Protective Role For Wholegrainsmentioning

confidence: 99%

The potential role of phytochemicals in wholegrain cereals for the prevention of type-2 diabetes

Belobrajdic

Bird

2013

Nutr J

153

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Diets high in wholegrains are associated with a 20-30% reduction in risk of developing type-2 diabetes (T2D), which is attributed to a variety of wholegrain components, notably dietary fibre, vitamins, minerals and phytochemicals. Most phytochemicals function as antioxidants in vitro and have the potential to mitigate oxidative stress and inflammation which are implicated in the pathogenesis of T2D. In this review we compare the content and bioavailability of phytochemicals in wheat, barley, rice, rye and oat varieties and critically evaluate the evidence for wholegrain cereals and cereal fractions increasing plasma phytochemical concentrations and reducing oxidative stress and inflammation in humans. Phytochemical content varies considerably within and among the major cereal varieties. Differences in genetics and agro-climatic conditions explain much of the variation. For a number of the major phytochemicals, such as phenolics and flavanoids, their content in grains may be high but because these compounds are tightly bound to the cell wall matrix, their bioavailability is often limited. Clinical trials show that postprandial plasma phenolic concentrations are increased after consumption of wholegrain wheat or wheat bran however the magnitude of the response is usually modest and transient. Whether this is sufficient to bolster antioxidant defences and translates into improved health outcomes is still uncertain. Increased phytochemical bioavailability may be achieved through bio-processing of grains but the improvements so far are small and have not yet led to changes in clinical or physiological markers associated with reduced risk of T2D. Furthermore, the effect of wholegrain cereals and cereal fractions on biomarkers of oxidative stress or strengthening antioxidant defence in healthy individuals is generally small or nonexistent, whereas biomarkers of systemic inflammation tend to be reduced in people consuming high intakes of wholegrains. Future dietary intervention studies seeking to establish a direct role of phytochemicals in mediating the metabolic health benefits of wholegrains, and their potential for mitigating disease progression, should consider using varieties that deliver the highest possible levels of bioavailable phytochemicals in the context of whole foods and diets. Both postprandial and prolonged responses in systemic phytochemical concentrations and markers of inflammation and oxidative stress should be assessed along with changes related to health outcomes in healthy individuals as well as those with metabolic disease.

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Effects of supplementation with high-selenium wheat bread on selenium, glutathione peroxidase and related enzymes in blood components of New Zealand residents

Cited by 61 publications

References 39 publications

Serum antioxidants and inflammation predict red cell distribution width in older women: The Women's Health and Aging Study I

Serum antioxidants and inflammation predict red cell distribution width in older women: The Women's Health and Aging Study I

Assessment of requirements for selenium and adequacy of selenium status: a review

The potential role of phytochemicals in wholegrain cereals for the prevention of type-2 diabetes

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