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DRI DIETARY REFERENCE INTAKES FOR Vitamin C, Vitamin E, Selenium, and Carotenoids
ducted a double-blind, 7-week pilot study and a 3-month main study evaluating the prophylactic effect of 1,000 mg/day of vitamin C on colds in 172 and 642 children, respectively, ages 8 to 9 years. Reported side effects, including stomach pains, skin rash, headache, diarrhea, and nausea, were observed in about 3 percent of the children, which was no different from the control group and was not dose related. Therefore, this study could be used to support a NOAEL of 1,000 mg/day.
Another study tested the effectiveness of a megavitamin regimen including 3 g/day of ascorbic acid for 3 months on attention deficit disorder (ADD) in 41 children ages approximately 7 to 11 years (Haslam et al., 1984). Forty-two percent of the children developed elevation of serum aminotransferases, and it was concluded that the regimen (which was ineffective) should not be used to treat ADD. It is unlikely that the increases in serum aminotransferases were due to the high acsorbic acid intake since no such effects of high vitamin C intakes have been reported by other investigators. Nevertheless, this study appears consistent with the adult data indicating a LOEAL at intakes of 3 g/day. However, this study cannot be utilized to establish a UL for children as the vitamin C was part of a mega-vitamin and the contribution of vitamin C to the results cannot be determined.
Because the results of these studies (particularly the study by Ludvigsson et al., 1977) are consistent with the data on adverse effects in adults on a body weight basis, the UL values for toddlers, children, and adolescents are extrapolated based on body weight differences from those established for adults as described in Chapter 4 using reference weights from Chapter 1 (Table 1-1). The calculated UL is rounded to the nearest 50 mg.
Pregnancy. No evidence of maternal toxicity of excess vitamin C intakes was found. However, because vitamin C is actively transported from maternal to fetal blood, there could be a potential for maternal intake of megadoses of vitamin C during pregnancy to lead to markedly elevated concentrations of vitamin C in the fetus. There is one anecdotal report (Cochrane, 1965) of possible fetal vitamin C dependence induced in utero in two infants, whose mothers consumed 400 mg/day of vitamin C during pregnancy. Although the infants developed scurvy during the first few weeks of life, the observation was complicated by the relatively high incidence of scurvy in the region of Canada in which the infants were born. Other concerns for high vitamin C concentrations in infants stem from reports of hemolysis (Ballin et al., 1988) and possible increased