2. Vitamin C Doses Over 500–1,000 mg Daily
Large doses are converted to oxalate, raising the risk of kidney stones in susceptible patients.
The American Journal of Kidney Diseases (2023) recommends staying under 500 mg supplemental C for most CKD patients.
Safer choice: 1–2 oranges or a handful of strawberries provide plenty without excess.
3. High-Dose Vitamin D Without Medical Supervision
While many CKD patients are low in activated vitamin D, self-dosing high amounts (≥4,000 IU) can raise blood calcium dangerously.
Kidney International (2021) stresses prescription active forms (calcitriol, etc.) over OTC D2/D3 in later stages.
Safer choice: Get a 25-hydroxy vitamin D blood test first, then follow your doctor’s exact dose.
4. Vitamin E Doses Above 400 IU Daily
High doses may increase bleeding risk, especially in patients on blood thinners or with platelet issues common in CKD.
Nephrology Dialysis Transplantation (2024) advises caution above the RDA.
Safer choice: Almonds, sunflower seeds, and spinach provide gentle, natural vitamin E.
5. Excess Vitamin K Supplements (Especially K1 > 1,000 mcg)
Can interfere with warfarin and other anticoagulants many kidney patients take.
Even in non-warfarin patients, sudden large changes affect INR stability.
Safer choice: Consistent, moderate intake from leafy greens is usually fine — just keep it steady and tell your doctor.
