Vitamin D supplements for patients with chronic kidney disease might not be helping: study
Vitamin D supplements are often recommended to patients with chronic kidney disease, but a new study presented at MLS Future Forum suggests it could be a waste of time.
Hannah Guy, an undergraduate at University of the West of England, won a poster prize for her research, entitled ‘The impact/effect of vitamin D and calcium supplementation on the kidney function and quality of life of patients with chronic kidney disease (CKD): a systematic review (and meta-analysis)’.
Her systematic review, conducted under the supervision of Faatiha Niyi-Odumosu, evaluates the effects of vitamin D and Calcium supplementation on kidney function and quality of life in chronic kidney disease patients.
“No significant effects of vitamin D supplementation on kidney function or quality of life in CKD patients were observed, challenging the widespread assumption of its benefits. These findings contribute to the debate regarding the efficacy of vitamin D and calcium supplementation providing valuable information for future research and clinical practice,” she said.
Quality of life
Chronic Kidney Disease (CKD) is a progressive condition that affects over 10% of the global population. One of the significant complications of CKD is the disruption of the calcium and phosphate balance, leading to conditions like secondary hyperparathyroidism and bone mineral disorders. These complications can severely impair the quality of life of CKD patients.
Vitamin D supplementation has become a standardised therapy for managing these complications, aiming to improve calcium phosphate metabolism and prevent bone mineral disorders. However, there is a lack of evidence on the effectiveness of these treatments, with conflicting evidence from studies.
Furthermore, there is a lack of studies that actually evaluate the effectiveness of calcium supplementation despite its widespread use as a standard treatment for hyperphosphatemia. Hannah’s systematic review sought to evaluate the real impact of vitamin D and calcium supplementation on kidney function and QoL in CKD patients, addressing the critical gap in the current research and literature.
Reviewing studies
“My review involved searching multiple databases such as PubMed, Google Scholar, Science Direct and EBSCO for relevant studies. The research protocol was registered on PROSPERO to ensure transparency. A total of 15 studies were selected, representing a global sample of CKD patients across 10 countries with various stages of the disease,” she said.
“My analysis found no significant improvements in kidney function or quality of life following vitamin D supplementation. While there was a reduction in PTH levels after supplementation, the change was not statistically significant.
“Additionally, despite some positive changes in bone turnover markers, there was no improvement in bone mineral density. Furthermore, there was a notable lack of studies on calcium supplementation, making it difficult to draw conclusions about its effectiveness or its risks in CKD management.“
Gaps in literature
The findings highlight significant gaps in the current literature, particularly regarding the combined effects of vitamin D and calcium supplementation on CKD outcomes, Hannah said.
One of the most surprising findings was the lack of significant improvements in kidney function and quality of life, she added.
“Despite the fact that vitamin D supplements are widely recommended to CKD patients, the evidence from the studies included in my review showed no statistically significant effects. Additionally, the reduction in PTH levels, although a common therapeutic target, did not result in any meaningful improvements.
“Furthermore, the limited research on calcium supplementation further surprised me, given its importance in CKD management. From prior research I understand that there are concerns over the disruption of the calcium balance leading to potential risks such as vascular calcification - however, that highlights the need for more rigorous clinical trials to assess their safety and efficacy in CKD patients.”
Clinical trials
Since there is a lack of studies on the effectiveness and risks of calcium supplementation in CKD patients, more rigorous long-term clinical trials should be conducted to evaluate its impact on kidney function, bone health and cardiovascular risks, Hannah suggested.
“This research should also explore the long term effects. Future studies could also further examine the impact of vitamin D and calcium supplementation at different stages of CKD to determine whether these treatments are more effective at certain stages of the disease,” she said.
“Would earlier interventions have more of a significant impact on the disease progression? There should also be a focus on the combined treatment of vitamin D and calcium supplementation.”
For more research from MLS Future Forum 2025 and updates for 2026, sign up to the newsletter.