| 1. |
- Johansson, Clara, et al.
(author)
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Down-regulation of oxidative DNA lesions in human mononuclear cells after antioxidant supplementation correlates to increase of gamma-tocopherol
- 2008
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In: International Journal for Vitamin and Nutrition Research. - : Hogrefe Publishing Group. - 0300-9831 .- 1664-2821. ; 78:4-5, s. 183-194
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Journal article (peer-reviewed)abstract
- The protective effect of vitamin E supplements has been questioned, possibly because they often contain only alpha-tocopherol, and recent studies indicate that gamma-tocopherol also has important properties. The aim of this study was to investigate whether the levels of DNA lesions in middle-aged, overweight males could be reduced by consumption of low doses of an antioxidant supplement for six weeks, designed to imitate a balanced diet. The participants (n=60) were randomly divided into: placebo, single-, and double-dose groups. Genotoxic and oxidative DNA lesions in mononuclear cells were measured with the Comet assay, before and after supplement administration. Furthermore, a cell study was performed to investigate if pre-incubation of a human lung cell line (A549) with alpha- and gamma-tocopherol (5 and 50 microM for 23 hours) could protect against induced oxidative DNA lesions as measured by the Comet assay. The level of oxidative DNA lesions in the double-dose group was significantly lower than in the control group. Oxidative DNA lesions correlated only to changes in serum gamma-tocopherol, and not alpha-tocopherol. In the cell study, only gamma-tocopherol protected cells against induced oxidative DNA lesions. We therefore hypothesize that gamma-tocopheol rather than alpha-tocopherol is involved in reducing oxidative DNA lesions.
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| 2. |
- Rytter, Elisabet, 1960-, et al.
(author)
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Biomarkers of oxidative stress in overweight men are not influenced by a combination of antioxidants
- 2010
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In: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 44:5, s. 522-528
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Journal article (peer-reviewed)abstract
- The effect of antioxidant supplementation on biomarkers of oxidative stress was investigated in a 6-week intervention study in 60 overweight men. The supplement contained a combination of antioxidants aiming to correspond to the antioxidant content found in a diet rich in fruit and vegetables. Placebo, single or double dose of antioxidants was provided to the subjects. Metabolic variables, plasma antioxidants and biomarkers of oxidative stress (lipid peroxidation and DNA damage) were measured. No effect of supplementation on biomarkers of oxidative stress was observed. Both intervention groups showed substantial increases of plasma antioxidants. This study demonstrated that supplementation with a combination of antioxidants did not affect lipid peroxidation and DNA damage in overweight men, despite increased concentrations of plasma antioxidants. The absence of antioxidant supplement effect might possibly be explained by the chosen study group having a normal level of oxidative stress, duration of the intervention and/or doses of antioxidants.
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| 3. |
- Rytter, Elisabet, et al.
(author)
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Glycaemic status in relation to oxidative stress and inflammation in well-controlled type 2 diabetes subjects
- 2009
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In: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 101:10, s. 1423-1426
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Journal article (peer-reviewed)abstract
- The aim of the present observational study was to investigate the relationships between glycaemic status and levels of oxidative stress and inflammation in well-controlled type 2 diabetes subjects. Metabolic variables (weight, BMI, waist circumference (waist), blood glucose, glycated Hb (HbA1c), insulin, blood lipids), biomarkers of oxidative stress (8-iso-PGF2α, malondialdehyde, 8-oxo-7,8-dihydro-2'-deoxyguanosine, formamido pyrimidine glycosylase-sites, frequency of micronucleated erythrocytes, nitrotyrosine) and inflammatory markers (high sensitivity C-reactive protein (hsCRP), IL-6, cyclo-oxygenase-catalyzed PGF2α-metabolite) were measured. Fifty-six patients (thirty women and twenty-six men, age 62.3 (SD 7.0) years, HbA1c 6.1 (SD 0.9) %, BMI 28.3 (SD 3.8) kg/m2, waist 99.6 (SD 11.1) cm) were included in the study. HbA1c (r 0.29, P=0.03) and blood glucose (r 0.33, P=0.01) correlated positively with 8-iso-PGF2α. Positive correlations were also observed between HbA1c and nitrotyrosine (r 0.42, P=0.01), waist and hsCRP (r 0.37, P=0.005), hsCRP and IL-6 (r 0.61, P<0.0001) and between PGF2α-metabolite and 8-iso-PGF2α (r 0.27, P=0.048). The present study indicates that glycaemic status is associated with oxidative stress even in subjects with well-controlled type 2 diabetes. Furthermore, inflammation was more related to abdominal obesity than to glycaemic control. A large number of biomarkers of oxidative stress and inflammation were investigated, but only a few associations were found between the markers. This could be due to the fact that none of these biomarkers biosynthesises via similar pathways or simultaneously owing to their diverse nature and origin.
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| 4. |
- Rytter, Elisabet, 1960-, et al.
(author)
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Supplementation with a combination of antioxidants does not affect glycaemic control, oxidative stress or inflammation in type 2 diabetes subjects
- 2010
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In: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 44:12, s. 1445-1453
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Journal article (peer-reviewed)abstract
- The present clinical trial examined the influence of a supplement, containing a combination of antioxidants extracted from fruit, berries and vegetables, on levels of plasma antioxidants (tocopherols, carotenoids and ascorbate), glycaemic control (blood glucose, HbA1c, insulin), oxidative stress biomarkers (F2-isoprostane, malondialdehyd, nitrotyrosine, 8-oxo-7, 8-dihydro-2'-deoxyguanosine, formamidopyrimidine glycosylase sites, frequency of micronucleated erythrocytes) and inflammatory markers (interleukin-6, C-reactive protein, prostaglandin F2α-metabolite) in type 2 diabetes. Forty subjects were randomly assigned to control, single or double dose group and completed the study. In summary, 12 weeks of antioxidant supplementation did neither affect glycaemic control nor the levels of biomarkers of oxidative stress or inflammation, despite substantially increased plasma concentrations of antioxidants. The absence of an effect may be explained by the selected study subjects with relatively well-controlled diabetes, a high intake of fruit and vegetable and levels of plasma antioxidants, biomarkers of oxidative stress and inflammatory markers comparable to those found in healthy subjects.
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| 5. |
- Åsgård, Rikard, et al.
(author)
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High intake of fruit and vegetables is related to low oxidative stress and inflammation in a group of patients with type 2 diabetes
- 2007
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In: Scandinavian Journal of Food and Nutrition. - : Informa UK Limited. - 1748-2976 .- 1748-2984. ; 51:4, s. 149-158
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Journal article (peer-reviewed)abstract
- Background : Patients with type 2 diabetes have increased levels of oxidative stress and inflammation. A high fruit and vegetable intake may be beneficial. Objective : To study whether fruit and vegetable intake and levels of plasma antioxidants relate to markers of oxidative stress and inflammation in a group of patients with type 2 diabetes. Further, to investigate whether plasma antioxidants are good biomarkers for intake of fruit and vegetables. Design : Patients with type 2 diabetes were studied. Their dietary intake and levels of plasma antioxidants, and markers of oxidative stress and inflammation were analysed. Results : Fruit and vegetable intake was inversely related to oxidative stress. Plasma carotenoids were negatively correlated with inflammation. The plasma levels of -carotene and β-carotene showed strongly positive associations with fruit and vegetable intake. Conclusions : The results suggest that fruit and vegetable intake may decrease oxidative stress and inflammation in this group of patients. An increased intake of fruit and vegetables can therefore be beneficial for patients with type 2 diabetes, since these patients are documented to have raised oxidative stress and inflammation. The study support the usefulness of plasma -carotene and β-carotene as biomarkers for fruit and vegetable intake.
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