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 (HbA 1c ), insulin, blood lipids), biomarkers of oxidative stress (8-iso-PGF 2a , malondialdehyde, 8-oxo-7,8-dihydro-2 0 -deoxyguanosine, formamido pyrimidine glycosylase-sites, frequency of micronucleated erythrocytes, nitrotyrosine) and inflammatory markers (high sensitivity C-reactive protein (hsCRP), IL-6, cyclo-oxygenase-catalyzed PGF 2a -metabolite) were measured. Fifty-six patients (thirty women and twenty-six men, age 62·3 (SD 7·0) years, HbA 1c 6·1 (SD 0·9) %, BMI 28·3 (SD 3·8) kg/m 2 , waist 99·6 (SD 11·1) cm) were included in the study. HbA 1c (r 0·29, P¼ 0·03) and blood glucose (r 0·33, P¼0·01) correlated positively with 8-iso-PGF 2a . Positive correlations were also observed between HbA 1c and nitrotyrosine (r 0·42, P¼ 0·01), waist and hsCRP (r 0·37, P¼0·005), hsCRP and IL-6 (r 0·61, P,0·0001) and between PGF 2a -metabolite and 8-iso-PGF 2a (r 0·27, P¼ 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.

Metformin compared with placebo has beneficial effects on anthropometric and metabolic indicators in the management of childhood obesity.

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 (F(2)-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 F(2α)-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.

BackgroundPatients with type 2 diabetes have increased levels of oxidative stress and inflammation. A high fruit and vegetable intake may be beneficial.ObjectiveTo 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.DesignPatients with type 2 diabetes were studied. Their dietary intake and levels of plasma antioxidants, and markers of oxidative stress and inflammation were analysed.ResultsFruit and vegetable intake was inversely related to oxidative stress. Plasma carotenoids were negatively correlated with inflammation. The plasma levels of α-carotene and β-carotene showed strongly positive associations with fruit and vegetable intake.ConclusionsThe 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 α-carotene and β-carotene as biomarkers for fruit and vegetable intake.

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