Effect of vitamin D supplementation on vitamin D status and bone turnover markers in young adults.

OBJECTIVE: To assess the vitamin D status of healthy young people living in Northern Ireland and the effect of vitamin D supplementation on vitamin D status and bone turnover. DESIGN: Double-blinded randomised controlled intervention study. SETTING: University of Ulster, Coleraine, Northern Ireland. SUBJECTS: In total, 30 apparently healthy students (15 male and 15 female subjects), aged 18-27 years, were recruited from the university, with 27 completing the intervention. INTERVENTIONS: Subjects were randomly assigned, to receive either 15 microg (600 IU) vitamin D(3) and 1,500 mg calcium/day (vitamin D group), or 1,500 mg calcium/day (control group) for 8 weeks between January and March. Vitamin D status, bone turnover markers, serum calcium and parathyroid hormone concentrations were measured at baseline and post intervention. RESULTS: At baseline, vitamin D status was low in both the vitamin D group (47.9 (s.d. 16.0)) and the control group (55.5 (s.d. 18.6) nmol/l 25(OH)D). Post intervention vitamin D status was significantly higher in the vitamin D-treated group (86.5 (s.d. 24.5)) compared to the control group (48.3 (s.d. 16.8) nmol/l) (P<0.0001). There was no significant effect of supplementation on bone turnover markers or PTH concentrations. CONCLUSIONS: This study suggests that young adults in Northern Ireland do not consume an adequate daily dietary intake of vitamin D to maintain plasma vitamin D concentrations in the wintertime. A daily supplement of 15 microg vitamin D(3) significantly increased vitamin D status in these individuals to levels of sufficiency. Achievement of an optimum vitamin D status among young adults may have future positive health implications.

Copper supplementation has no effect on markers of DNA damage and liver function in healthy adults (FOODCUE project).

BACKGROUND/AIMS: Copper is routinely used in the laboratory to promote oxidation in vitro. However, copper concentrations are million-fold higher than physiological concentrations and, in contrast, accumulating evidence suggests that copper may have an antioxidant role in vivo. The aim of this study was to provide data on how increased intake of copper affected mononuclear leukocyte DNA damage and liver function in healthy young free-living men and women. METHODS: The study design was a double-blind repeated crossover trial with treatment and intervening placebo periods, each of 6 weeks' duration. The following supplementations were given orally in sequence: CuSO(4) at a dose of 3 mg copper/day and copper amino acid chelates at doses of 3 and 6 mg copper/day. Oxidative DNA damage was assessed using a modification of the alkaline Comet assay incorporating an endonuclease III digestion step. The assessment of liver function was by measurement of the liver enzymes, alanine aminotransferase and L-gamma-glutamyltransferase. RESULTS: There was no significant alteration in mononuclear leukocyte DNA damage or on liver function after 6 weeks of copper supplementation at two doses (3 and 6 mg/day). CONCLUSIONS: Copper supplementation (giving total copper intake at the highest level of 7 mg/day) did not induce DNA damage or adversely affect liver function in healthy adults.

No effect of copper supplementation on biochemical markers of bone metabolism in healthy young adult females despite apparently improved copper status.

OBJECTIVE: To investigate the effects of increasing Cu intakes, above the usual dietary intake, on biomarkers of bone metabolism in healthy young adult females (aged 21-28 y) over a 4 week period. DESIGN: A double-blind, placebo-controlled randomised repeat crossover Cu supplementation trial. SETTING: The study was conducted at the Royal Veterinary and Agricultural University (RVAU), Copenhagen, Denmark. SUBJECTS: Sixteen healthy young adult females aged 20-28 y were recruited from among students at the RVAU. INTERVENTION: During the 4 week intervention periods in this randomised, crossover trial (3x4 weeks with a minimum 3 week wash-out period), each subject received, in addition to their usual diet, either 3 or 6 mg elemental Cu/day as CuSO4 or a matching placebo. On the last 3 days of each dietary period 24 h urines were collected. In addition, blood was collected on the last day of each dietary period. RESULTS: Serum Cu and erythrocyte superoxide dismutase (but not caeruloplasmin protein concentration or activity (putative indices of Cu status)) were significantly increased (P<0.05) after daily Cu supplementation with 3 and 6 mg/day for 4 weeks. Serum osteocalcin (biomarker of bone formation), urinary creatinine (Cr) concentration, urinary pyridinoline (Pyr)/Cr or deoxypyridinoline (Dpyr)/Cr excretion, or daily urinary Pyr or Dpyr excretion (biomarkers of bone resorption) were unaffected by Cu supplementation. CONCLUSION: Copper supplementation of the usual diet in healthy young adult females, while apparently improving Cu status, had no effect on biochemical markers of bone formation or bone resorption over 4 week periods. SPONSORSHIP: Funding from the European Commission.

Copper supplementation in humans does not affect the susceptibility of low density lipoprotein to in vitro induced oxidation (FOODCUE project).

The oxidative modification of low-density lipoprotein cholesterol (LDL) has been implicated in the pathogenesis of atherosclerosis. Copper (Cu) is essential for antioxidant enzymes in vivo and animal studies show that Cu deficiency is accompanied by increased atherogenesis and LDL susceptibility to oxidation. Nevertheless, Cu has been proposed as a pro-oxidant in vivo and is routinely used to induce lipid peroxidation in vitro. Given the dual role of Cu as an in vivo antioxidant and an in vitro pro-oxidant, a multicenter European study (FOODCUE) was instigated to provide data on the biological effects of increased dietary Cu. Four centers, Northern Ireland (coordinator), England, Denmark, and France, using different experimental protocols, examined the effect of Cu supplementation (3 or 6 mg/d) on top of normal Cu dietary intakes or Cu-controlled diets (0.7/1.6/6.0 mg/d), on Cu-mediated and peroxynitrite-initiated LDL oxidation in apparently healthy volunteers. Each center coordinated its own supplementation regimen and all samples were subsequently transported to Northern Ireland where lipid peroxidation analysis was completed. The results from all centers showed that dietary Cu supplementation had no effect on Cu- or peroxynitrite-induced LDL susceptibility to oxidation. These data show that high intakes (up to 6 mg Cu) for extended periods do not promote LDL susceptibility to in vitro-induced oxidation.

Response of putative indices of copper status to copper supplementation in human subjects.

No sensitive functional index is currently available to assess Cu status in healthy human populations. This study evaluated the effect of Cu supplementation on putative indices of Cu status in twelve women and twelve men, aged between 22 and 45 years, who participated in a double-blind placebo controlled crossover study. The study consisted of three 6-week supplementation regimens of 3 mg CuSO4, 3 mg Cu-glycine chelate and 6 mg Cu-glycine chelate, each separated by placebo periods of equal length. Women had significantly higher caeruloplasmin oxidase activity (P < 0.001), caeruloplasmin protein concentration (P < 0.05), and serum diamine oxidase activity (P < 0.01) at baseline than men. Erythrocyte and leucocyte superoxide dismutase activity, leucocyte cytochrome c oxidase activity, and erythrocyte glutathione peroxidase activity did not respond to Cu supplementation. Platelet cytochrome c oxidase activity was significantly higher (P < 0.01), after supplementation with 6 mg Cu-glycine chelate in the total group and in women but did not change in men. Caeruloplasmin oxidase activity was significantly higher (P < 0.05), in men after supplementation with 3 mg Cu-glycine chelate, while caeruloplasmin protein concentration was significantly lower in men after supplementation with 6 mg Cu-glycine chelate (P < 0.05). Serum diamine oxidase activity was significantly higher after all supplementation regimens in the total group and in both men and women (P < 0.01). These results indicate that serum diamine oxidase activity is sensitive to changes in dietary Cu intakes and may also have the potential to evaluate changes in Cu status in healthy adult human subjects.

The effect of copper supplementation on red blood cell oxidizability and plasma antioxidants in middle-aged healthy volunteers.

A multicenter European study (FoodCue) was undertaken to provide data on the significance of increased dietary copper as a pro-oxidant or antioxidant in vivo. The present work describes the effect of Cu supplementation on (2,2'-azo-bis(2-amidinopropane) hydrochloride (AAPH)-induced red blood cell oxidation in middle-aged people. Double-blinded copper supplementation was achieved in 26 healthy volunteers (50-70 years) with pills containing 3 mg CuSO(4), 3 mg Cu glycine chelate (CuG) and 6 mg CuG. Each 6 week supplementation period was preceded and followed by 6 weeks of washout (WO) on placebo. The results show significant increases in time necessary to achieve 50% hemolysis (LT(50)) after 3CuSO(4) and 6CuG compared with values after WO periods. Cu supplementation did not increase the levels of (Cu,Zn)SOD activity in red blood cells. Resistance to hemolysis was significantly and positively correlated (r =.30, p <.01) with alpha- and beta-carotene content in the plasma. Together, these data suggest that intake of copper as high as 7 mg/d has no pro-oxidant activity and may rather result in protection of red blood cells against oxidation. The decreased oxidizability of red blood cells did not result from increased (Cu,Zn)SOD activity and may occur through other mechanisms such as changes in membrane antioxidant content.

No effect of copper supplementation on biochemical markers of bone metabolism in healthy adults.

The influence of Cu supplementation of the usual diet for 6 weeks on biochemical markers of bone turnover and on putative indices of Cu status was investigated in healthy adults (twelve male and twelve female) aged 22-46 years, who participated in a double-blind placebo-controlled repeated crossover study. The study consisted of three 6-week supplementation regimens of 3 mg CuSO4, 3 mg Cu-glycine chelate (CuGC), and 6 mg CuGC, each separated by placebo periods of equal length. During baseline and on the last day of each dietary period, fasting morning first-void urine and fasting blood serum, plasma and erythrocytes were collected. The habitual dietary Cu intakes in males and females were approximately 1.4 and 1.1 mg/d respectively. Females had significantly higher (50%) plasma caeruloplasmin (Cp) protein concentrations than males at baseline. Cu supplementation had no effect on erythrocyte superoxide dismutase (SOD, EC 1.15.1.1) activity or plasma Cp protein (putative indices of Cu status) in the total group. Similarly, serum osteocalcin (a marker of bone formation), urinary creatinine (Cr) concentration, urinary pyridinoline: Cr or deoxypyridinoline: Cr excretion (markers of bone resorption) were unaffected in either the total group or in males and females separately, by any Cu supplementation regimen. It is concluded that Cu supplementation of the usual diet in healthy adult males and females had no effect on biochemical markers of bone formation or bone resorption over 6-week periods.