Predictors of vitamin D-containing supplement use in the Australian population and associations between dose and serum 25-hydroxyvitamin D concentrations

Despite concerns about vitamin D deficiency in the Australian population, little is known about the prevalence and predictors of vitamin D-containing supplement use. We described the use of vitamin D-containing supplements, and investigated associations between supplemental vitamin D intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, using a single 24-h dietary recall from the 2011-2013 Australian Health Survey (n = 12,153; ages ≥ 2 years). Multiple regression models were used to investigate predictors of vitamin D-containing supplement use in adults, and associations between dose and serum 25(OH)D concentrations/vitamin D sufficiency (≥50 nmol/L), adjusting for potential confounders. The prevalence of vitamin D-containing supplement use was 10%, 6% and 19% in children, adolescents and adults, respectively. Predictors of vitamin D-containing supplement use in adults included being female, advancing age, higher educational attainment, higher socio-economic status, not smoking, and greater physical activity. After adjusting for potential confounders, a 40 IU (1 µg) increase in vitamin D intake from supplements was associated with an increase of 0.41 nmol/L in serum 25(OH)D concentrations (95% CI 0.35, 0.47; p < 0.001). However, the prevalence of vitamin D-containing supplement use was generally low in the Australian population, particularly for single vitamin D supplements, with most supplement users obtaining only low levels of vitamin D from other supplement types.

Highly specific changes in antioxidant levels and lipid peroxidation in Parkinson's disease and its progression : disease and staging biomarkers and new drug targets.

There is evidence that immune-inflammatory, stress of reactive oxygen and nitrogen species (IO&NS) processes play a role in the neurodegenerative processes observed in Parkinson's disease (PD). The aim of the present study was to investigate peripheral IO&NS biomarkers in PD. We included 56 healthy individuals and 56 PD patients divided in two groups: early PD stage and late PD stage. Plasma lipid hydroperoxides (LOOH), malondialdehyde (MDA), nitric oxide metabolites (NOx), sulfhydryl (SH) groups, catalase (CAT) activity, superoxide dismutase (SOD) activity, paraoxonase (PON)1 activity, total radical trapping antioxidant parameter (TRAP) and C-reactive protein (CRP) were measured. PD is characterized by increased LOOH, MDA and SOD activity and lowered CAT activity. A combination of five O&NS biomarkers highly significantly predicts PD with a sensitivity of 94.5% and a specificity of 86.8% (i.e., MDA, SOD activity, TRAP, SH-groups and CAT activity). The single best biomarker of PD is MDA, while LOOH and SOD activity are significantly associated with late PD stage, but not early PD stage. Antiparkinson drugs did not affect O&NS biomarkers, but levodopa+carbidopa significantly increased CRP. It is suggested that MDA may serve as a disease biomarker, while LOOH and SOD activity are associated with late PD stage characteristic. New treatments for PD should not only target dopamine but also lipid peroxidation.