Vitamin C Deficiency Common in Patients with Chronic Kidney Disease: Study
A new study published in The American Journal of Clinical Nutrition found a strong link between chronic kidney disease (CKD) and vitamin C (VitC) deficiency, showing that individuals living with impaired kidney function are far more likely to suffer from inadequate VitC levels when compared to healthy counterparts.
The cross-sectional study examined VitC status in 62 patients undergoing dialysis, 41 with advanced CKD (stages 4/5), and 42 kidney transplant recipients (KTRs) which made up the CKD group. Their outcomes were compared to 447 living kidney donors and 385 healthy controls, classified as the healthy population.
The plasma VitC concentrations were measured and categorized, where deficiency was defined as <10 μmol/L, inadequacy as 10–35 μmol/L. In CKD patients, daily dietary intake was assessed through 24-hour food recalls, while VitC losses during dialysis sessions were also measured.
The healthy controls registered the highest median plasma VitC levels at 58 μmol/L, with just 14% falling into inadequate or deficient ranges. Kidney donors followed closely at 50 μmol/L, with 22% showing insufficiency. Also, CKD populations showed markedly lower levels, where transplant recipients recorded a median of 37 μmol/L with nearly half (48%) inadequately nourished, dialysis patients had 33 μmol/L with 58% affected, and those with CKD stage 4/5 showed the lowest at just 22 μmol/L, with 80% categorized as inadequate or deficient.
While both transplant recipients and CKD stage 4/5 patients consumed relatively low amounts of VitC daily (averaging around 55 mg), dialysis patients reported higher intake, averaging 113 mg, largely due to supplementation. However, dialysis itself was found to strip away significant amounts of VitC, which averaged 58 mg per conventional session and up to 128 mg in nocturnal hemodialysis.
This study observed that kidney function, as measured by estimated glomerular filtration rate, was positively linked to plasma VitC levels, even after adjusting for confounders. This suggests that reduced kidney performance independently contributes to diminished VitC availability. Overall, these findings suggest VitC inadequacy common among CKD patients, driven by insufficient intake and nutrient loss during dialysis. This stresses the need for routine monitoring of VitC levels in these patients, as well as carefully designed supplementation strategies.
Source:
Doorenbos, C. S. E., Bolhuis, D. P., Ipema, K., Jr, Duym, E. M., Westerhuis, R., Stegmann, M. E., Franssen, C. F., Bakker, S. J., Gomes-Neto, A. W., Navis, G., Berger, S. P., Özyilmaz, A., & TransplantLines Investigators. (2025). Vitamin C status across the spectrum of chronic kidney disease and healthy controls: a cross-sectional study. The American Journal of Clinical Nutrition. https://doi.org/10.1016/j.ajcnut.2025.09.008
