oxidative damage (Powers et al., 1995) in premature infants. However, these effects are not well documented, and do not warrant a separate UL for pregnant females.

Lactation. Byerley and Kirksey (1985) noted that the vitamin C composition of human milk was not affected by maternal vitamin C intake ranging from 156 to 1,123 mg/day and that urinary excretion increased as intake increased over 200 mg/day, suggesting that mammary tissue becomes saturated with vitamin C. One woman ingested 4,000 mg/day of vitamin C as a supplement; no toxic effects of the excess vitamin intake were noted in the mother. Her milk content of vitamin C was 100.5 mg/L, which was on the high end of values reported for human milk, but not reflective of the high intake (Anderson and Pittard, 1985). Based on these findings, the ULs for lactating adolescents and women are not different from those of nonlactating females.

Individuals with hemochromatosis, glucose-6-phosphate dehydrogenase deficiency, and renal disorders may be especially susceptible to adverse effects of excess vitamin C intake and therefore should be cautious about ingesting more vitamin C than the Recommended Dietary Allowance (RDA). Vitamin C intakes of 250