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Influence of Ascorbic Acid, Zinc, Iron, Sucrose and Fructose on Copper Status
"Adverse effects of high intakes of AA on Cu utilization are recognized in several species: rats (Van Campen and Gross, 1968; Johnson, 1986; Johnson and Murphy, 1988a), chicks (Carlton and Henderson, 1964, 1965; Hill and Starcher, 1965), rabbits, (Hunt and Carlton, 1965; Hunt et al., 1970), guinea pigs (Milne and Omaye, 1980; Smith and Bidlack, 1980; Omaye et al., 1986), monkeys (Milne et al., 1981), and humans (Finley and Cerklewski, 1983, Jacob et al., 1987). This antagonism between' AA and Cu may be beneficial when Cu intakes are excessive. High intakes of AA decreased the toxicity of excess dietary Cu in young pigs (Gipp et al., 1974).
The effects of high intakes of AA have usually been studied during Cu deficiency. Laboratory animals fed Cu-deficient diets supplemented with 1-5% AA have higher mortality rates, increased cardiac and/or vascular abnormalities, lower body weights, and lower hematocrit and hemoglobin levels than control animals. Liver Cu levels were not consistently decreased in animals fed Cu-deficient diets supplemented with AA for several weeks (Johnson, 1986; Johnson and Murphy, 1988a; Hill and Starcher, 1965; Hunt et al., 1970; Van Campen and Gross; 1968). However, in short-term studies with orally administered radiolabeled Cu, AA decreased the absorption of Cu from ligated intestinal segments, and decreased the retention of Cu in the liver and whole body of rats (Hill and Starcher, 1965; Van Campen and Gross, 1968). Thus, it is hypothesized that AA impairs Cu utilization through decreased Cu absorption or through increased turnover of Cu.
Although it is widely accepted that AA influences Cu utilization in laboratory animals, there is little information on the influence of AA on Cu status in humans. Ingestion of 1500 mg AA/day for 52 days by young adult men significantly decreased serum ceruloplasmin activity by 26% and tended to lower serum Cu; serum Cu levels were significantly increased 20 days after the AA supplements were discontinued (Finley and Cerklewski, 1983). A small but non-significant decrease in plasma ceruloplasmin protein was observed after administration of 1000 mg of AA for 60 days to institutionalized elderly (Schorah et al., 1981). An intake of 605 mg AA/day for 3 weeks significantly decreased ceruloplasmin activity, but did not decrease immunoreactive ceruloplasmin, serum Cu or the percent absorption of Cu in adult men (Jacob et al., 1987).
It has been suggested that AA has a specific reducing effect on the redox center, Cu(II), of ceruloplasmin; this would explain why the level of ceruloplasmin activity, but not ceruloplasmin protein, is most affected during exposure to high levels of AA (Jacob et al., 1987). It is also possible that the effects of AA on Cu status are dose related and adverse effects are not evident in humans until the intake of AA is in the range of 1500 mg/day (Finley and Cerklewski, 1983)."
Vitamin C overdose/deficiency symptoms, benefits, side effects
https://www.researchgate.net/public...r_a_recommended_dietary_allowance?ev=auth_pub
"Adverse effects of high intakes of AA on Cu utilization are recognized in several species: rats (Van Campen and Gross, 1968; Johnson, 1986; Johnson and Murphy, 1988a), chicks (Carlton and Henderson, 1964, 1965; Hill and Starcher, 1965), rabbits, (Hunt and Carlton, 1965; Hunt et al., 1970), guinea pigs (Milne and Omaye, 1980; Smith and Bidlack, 1980; Omaye et al., 1986), monkeys (Milne et al., 1981), and humans (Finley and Cerklewski, 1983, Jacob et al., 1987). This antagonism between' AA and Cu may be beneficial when Cu intakes are excessive. High intakes of AA decreased the toxicity of excess dietary Cu in young pigs (Gipp et al., 1974).
The effects of high intakes of AA have usually been studied during Cu deficiency. Laboratory animals fed Cu-deficient diets supplemented with 1-5% AA have higher mortality rates, increased cardiac and/or vascular abnormalities, lower body weights, and lower hematocrit and hemoglobin levels than control animals. Liver Cu levels were not consistently decreased in animals fed Cu-deficient diets supplemented with AA for several weeks (Johnson, 1986; Johnson and Murphy, 1988a; Hill and Starcher, 1965; Hunt et al., 1970; Van Campen and Gross; 1968). However, in short-term studies with orally administered radiolabeled Cu, AA decreased the absorption of Cu from ligated intestinal segments, and decreased the retention of Cu in the liver and whole body of rats (Hill and Starcher, 1965; Van Campen and Gross, 1968). Thus, it is hypothesized that AA impairs Cu utilization through decreased Cu absorption or through increased turnover of Cu.
Although it is widely accepted that AA influences Cu utilization in laboratory animals, there is little information on the influence of AA on Cu status in humans. Ingestion of 1500 mg AA/day for 52 days by young adult men significantly decreased serum ceruloplasmin activity by 26% and tended to lower serum Cu; serum Cu levels were significantly increased 20 days after the AA supplements were discontinued (Finley and Cerklewski, 1983). A small but non-significant decrease in plasma ceruloplasmin protein was observed after administration of 1000 mg of AA for 60 days to institutionalized elderly (Schorah et al., 1981). An intake of 605 mg AA/day for 3 weeks significantly decreased ceruloplasmin activity, but did not decrease immunoreactive ceruloplasmin, serum Cu or the percent absorption of Cu in adult men (Jacob et al., 1987).
It has been suggested that AA has a specific reducing effect on the redox center, Cu(II), of ceruloplasmin; this would explain why the level of ceruloplasmin activity, but not ceruloplasmin protein, is most affected during exposure to high levels of AA (Jacob et al., 1987). It is also possible that the effects of AA on Cu status are dose related and adverse effects are not evident in humans until the intake of AA is in the range of 1500 mg/day (Finley and Cerklewski, 1983)."
Vitamin C overdose/deficiency symptoms, benefits, side effects
https://www.researchgate.net/public...r_a_recommended_dietary_allowance?ev=auth_pub
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