Urinary Ascorbic Acid Levels Following the Withdrawal of Large Doses of Ascorbic Acid in Guinea Pigs

Abstract

Male guinea pigs received sodium ascorbate solution [equivalent to 1 g ascorbic acid/(kg body weight.d)] by intraperitoneal injection for 4 wk. During the ascorbic acid treatment period, plasma and urinary ascorbic acid levels rose markedly. Three weeks after the ascorbic acid treatment was withdrawn, mean urinary ascorbic acid levels were significantly lower than their corresponding basal levels. At both 2 and 5 wk after withdrawal of ascorbic acid treatment, mean plasma ascorbic acid levels were below normal. The results indicate that these animals had experienced a transient withdrawal effect after administration of large doses of ascorbic acid that lasted about 1 wk. This, in turn, indicates that the rate of ascorbic acid turnover was probably increased during treatment, and this effect persisted even after the ascorbic acid was withdrawn. Examination of data from each individual experimental animal revealed that the pattern of urinary ascorbic acid excretion after the withdrawal of large doses of ascorbic acid varied from animal to animal. Among the twelve experimental guinea pigs, seven had abnormally low urinary ascorbic acid levels 2-4 wk after the withdrawal of the large doses of ascorbic acid.

Ascorbic acid: Chemistry, biology and the treatment of cancer

“…Male guinea pigs that received ascorbate 1 g kg −1 body weight per day by i.p. for 4 weeks had elevated plasma and urinary levels; however, in the weeks after the treatment withdrawn, mean plasma and urinary ascorbate were significantly lower than normal [229]. It is unknown if a similar rebound effect would occur in human subjects following high doses i.v.…”

Orthomolecular Oncology Review: Ascorbic Acid and Cancer 25 Years Later

“…High doses of ascorbate make the urine acidic, thus preventing stone formation. There are various studies that have addressed this issue [135][136][137][138][139][140] and found no evidence of ascorbate increasing the risk of kidney stone formation.…”

Final Report of the Safety Assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as Used in Cosmetics1

“…Among the 12 treated animals, 7 had abnormally low urinary Ascorbic Acid levels 2 to 4 weeks after the withdrawal. At both weeks 2 and 5 after withdrawal, the mean plasma Ascorbic Acid levels were below normal (Tsao and Leung 1988).…”

“…Prenatal exposure to high maternal intake of Ascorbic Acid for 1 week, preceded and followed by the control diet, did not affect the postnatal catabolism of Ascorbic Acid in the offspring (Norkus and Rosso 1981). Tsao and Leung (1988) measured the urine and plasma from male Hartley guinea pigs (two groups with 12 animals each) colorimetrically for urinary and plasma levels of Ascorbic Acid. For the first four weeks both groups were fed a diet containing 0.1% Ascorbic Acid (40 mg/kg/day) and the basal levels of plasma and urinary Ascorbic Acid were measured.…”