Vitamin c effects on kidney function
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Vitamin C and Kidney Function: Protective and Risk Effects
Vitamin C Levels and Chronic Kidney Disease Risk
Higher serum vitamin C levels are linked to a lower risk of developing chronic kidney disease (CKD), albuminuria, and reduced estimated glomerular filtration rate (eGFR), especially in older adults. People with higher vitamin C levels tend to have better kidney function and a lower chance of CKD, suggesting that maintaining adequate vitamin C may help protect kidney health in the general population and particularly in those aged 65–80 years .
Vitamin C as an Antioxidant in Kidney Injury and Disease
Vitamin C’s antioxidant properties help reduce oxidative stress and inflammation, which are key contributors to kidney damage. Studies in animal models show that vitamin C can improve kidney function and reduce markers of oxidative stress in cases of chemically induced kidney injury, diabetic nephropathy, and nephrotoxicity from drugs like gentamicin. In these models, vitamin C lowered blood urea nitrogen, creatinine, and other markers of kidney dysfunction, and improved antioxidant enzyme levels 5710. Both oxidized and reduced forms of vitamin C have shown benefits in reversing age-related kidney damage and improving renal histology and function in older mice .
Vitamin C in Kidney Transplantation and Ischemia-Reperfusion Injury
Vitamin C supplementation in kidney transplant recipients may improve endothelial function and creatinine clearance, and help reduce the duration of delayed graft function (DGF) after transplantation. However, while vitamin C can decrease the length of DGF, it does not necessarily reduce its incidence. There are also potential interactions with transplant medications and laboratory tests, and rare risks such as kidney stones or hemolysis in susceptible individuals 69. In models of ischemia-reperfusion injury, vitamin C administered during reperfusion significantly reduced kidney dysfunction and tissue damage, with the most benefit seen at moderate doses (e.g., 200 mg/kg in rats). Higher doses did not provide additional benefit and may even cause harm .
High-Dose Vitamin C: Potential Risks
While moderate doses of vitamin C are generally beneficial, high-dose vitamin C can increase oxidative stress and cause kidney dysfunction in animal studies. Rats given very high doses of vitamin C showed significant increases in oxidative stress markers and kidney damage, suggesting that excessive supplementation should be avoided .
Vitamin C and Kidney Function in Perfusion and Immunity
In perfused kidney models, vitamin C increased antioxidant capacity and reduced oxidative stress, but did not significantly improve kidney function or reduce tissue injury in the short term . Additionally, vitamin C, sometimes in combination with curcumin, can help restore immune-related gene expression and improve kidney function in models of chemically induced nephrotoxicity .
Conclusion
Vitamin C plays a complex role in kidney health. Adequate levels are associated with reduced risk of CKD and improved kidney function, largely due to its antioxidant effects. Moderate supplementation can protect against various forms of kidney injury, including those related to diabetes, drugs, and transplantation. However, excessive doses may be harmful, increasing oxidative stress and causing kidney dysfunction. For most people, maintaining normal vitamin C levels through diet or moderate supplementation is likely beneficial for kidney health, but high-dose supplementation should be approached with caution, especially in those with existing kidney issues.
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