Testing the Hypothesis that Vitamin C Deficiency Is a Risk Factor for Clozapine-Induced Agranulocytosis Using Guinea Pigs and ODS Rats

Vitamin C deficiency – or hypovitaminosis C defined as a plasma concentration below 23 μm – is estimated to affect hundreds of millions of people in the Western world, in particular subpopulations of low socio-economic status that tend to eat diets of poor nutritional value. Recent studies by us have shown that vitamin C deficiency may result in impaired brain development. Thus, the aim of the present study was to investigate if a poor diet high in fat and cholesterol affects the vitamin C status of guinea pigs kept on either sufficient or deficient levels of dietary ascorbate (Asc) for up to 6 months with particular emphasis on the brain. The present results show that a high-fat and cholesterol diet significantly decreased the vitamin C concentrations in the brain, irrespective of the vitamin C status of the animal (P < 0·001). The brain Asc oxidation ratio only depended on vitamin C status (P < 0·0001) and not on the dietary lipid content. In plasma, the levels of Asc significantly decreased when vitamin C in the diet was low or when the fat/cholesterol content was high (P < 0·0001 for both). The Asc oxidation ratio increased both with low vitamin C and with high fat and cholesterol content (P < 0·0001 for both). We show here for the first time that vitamin C homoeostasis of brain is affected by a diet rich in fat and cholesterol. The present findings suggest that this type of diet increases the turnover of Asc; hence, individuals consuming high-lipid diets may be at increased risk of vitamin C deficiency.

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INTERRELATIONSHIP OF VITAMINS A AND C ON TISSUE UBIQUINONES AND STEROLS OF RATS AND GUINEA PIGS

Canadian Journal of Biochemistry ◽

10.1139/o67-086 ◽

1967 ◽

Vol 45 (6) ◽

pp. 749-756 ◽

Cited By ~ 3

Author(s):

W. E. J. Phillips

Keyword(s):

Ascorbic Acid ◽

Vitamin A ◽

Vitamin C ◽

Guinea Pig ◽

Guinea Pigs ◽

Vitamin A Deficiency ◽

Secondary Effect ◽

Vitamin C Deficiency ◽

Vitamins A And C ◽

Combined Deficiency

The effect of administration of ascorbic acid to normal or vitamin A-deficient rats was studied in relation to hepatic levels of ubiquinones and sterols. Similar studies were made on tissues from guinea pigs deficient in vitamin C, vitamin A, or both. Vitamin A deficiency increased the concentration of liver ubiquinones in the rat. Administration of ascorbate did not influence tissue levels of ubiquinones or sterols. Vitamin C deficiency increased the concentration of sterols but not of ubiquinones in the liver of the guinea pig. Vitamin A deficiency did not increase ubiquinones nor did a combined deficiency of vitamins A and C. A secondary effect of vitamin C deficiency in the vitamin A-deficient rat is not the cause of increased ubiquinone levels.

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Vitamin C Deficiency as a Risk Factor for Bell’s Palsy: A New Association

Cureus ◽

10.7759/cureus.21143 ◽

2022 ◽

Author(s):

Raktim Swarnakar ◽

Shiv L Yadav

Keyword(s):

Risk Factor ◽

Vitamin C ◽

Bell’S Palsy ◽

Bell's Palsy ◽

Vitamin C Deficiency ◽

New Association

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The effect of chronic marginal vitamin C deficiency on the α-tocopherol content of the organs and plasma of guinea-pigs

Cellular and Molecular Life Sciences ◽

10.1007/bf01955766 ◽

1982 ◽

Vol 38 (12) ◽

pp. 1454-1455 ◽

Cited By ~ 19

Author(s):

F. Hrubá ◽

V. Nováková ◽

E. Ginter

Keyword(s):

Vitamin C ◽

Guinea Pigs ◽

Tocopherol Content ◽

Vitamin C Deficiency

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Vitamin C deficiency in weanling guinea pigs: differential expression of oxidative stress and DNA repair in liver and brain

British Journal Of Nutrition ◽

10.1017/s0007114507787457 ◽

2007 ◽

Vol 98 (6) ◽

pp. 1116-1119 ◽

Cited By ~ 41

Author(s):

Jens Lykkesfeldt ◽

Gilberto Perez Trueba ◽

Henrik E. Poulsen ◽

Stephan Christen

Keyword(s):

Oxidative Stress ◽

Dna Repair ◽

Vitamin C ◽

Lipid Oxidation ◽

Protein Oxidation ◽

Guinea Pigs ◽

Vitamin C Deficiency ◽

Markers Of Oxidative Stress ◽

Selective Preservation ◽

The Brain

Neonates are particularly susceptible to malnutrition due to their limited reserves of micronutrients and their rapid growth. In the present study, we examined the effect of vitamin C deficiency on markers of oxidative stress in plasma, liver and brain of weanling guinea pigs. Vitamin C deficiency caused rapid and significant depletion of ascorbate (P < 0·001), tocopherols (P < 0·001) and glutathione (P < 0·001), and a decrease in superoxide dismutase activity (P = 0·005) in the liver, while protein oxidation was significantly increased (P = 0·011). No changes in lipid oxidation or oxidatively damaged DNA were observed in this tissue. In the brain, the pattern was markedly different. Of the measured antioxidants, only ascorbate was significantly depleted (P < 0·001), but in contrast to the liver, ascorbate oxidation (P = 0·034), lipid oxidation (P < 0·001), DNA oxidation (P = 0·13) and DNA incision repair (P = 0·014) were all increased, while protein oxidation decreased (P = 0·003). The results show that the selective preservation of brain ascorbate and induction of DNA repair in vitamin C-deficient weanling guinea pigs is not sufficient to prevent oxidative damage. Vitamin C deficiency may therefore be particularly adverse during the neonatal period.

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