A new expert consensus warns that taking high doses of vitamin D may be dangerous for people with chronic kidney disease (CKD). A panel of kidney specialists recommends avoiding “mega-doses” — defined as more than 100,000 international units (IU) — to reduce the risk of vitamin D toxicity and hypercalcemia (high calcium levels in the blood).​

Vitamin D deficiency is common in people with CKD and has been linked to poor health outcomes. However, the new guidelines emphasize that taking too much — especially active forms of vitamin D like calcitriol — may not improve health and could increase risks, particularly for people on dialysis or who have had a kidney transplant​.

The guidance comes from a joint panel representing the European Renal Association and the European Society for Paediatric Nephrology. After reviewing current research, the panel released updated guidance for healthcare providers on vitamin D use for people with CKD and kidney transplants​​.

Some key recommendations for people living with CKD include avoiding vitamin D doses over 100,000 IU as well as very high levels of 25-hydroxyvitamin D.

Getting Enough Vitamin D, Safely

If you have CKD, you may be at risk for vitamin D deficiency. But taking high doses without medical supervision can be dangerous. According to the kidney specialists on the panel, people with CKD should:

• Have their vitamin D levels checked regularly — especially after starting or adjusting supplements
• Get their vitamin D from food or supplements rather than from active vitamin D analogs, unless these are prescribed for severe health conditions
• Avoid over-the-counter supplements with excessive vitamin D content

Vitamin D plays an important role in bone health and immune function, but getting too much can lead to complications like kidney stones, blood vessel calcification, and high calcium levels​. If you’re considering vitamin D supplements, talk to your doctor about the right dosage for your condition.

Learn more about the relationship between vitamin D and kidney health.

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