Chronic kidney disease (CKD) and end-stage renal disease (ESRD) gradually impair kidney function, disrupting the balance of essential micronutrients. Some nutrients are prone to deficiency, while others accumulate due to impaired excretion, leading to toxicity. Patients undergoing hemodialysis are at an even higher risk of vitamin and mineral loss, making strict nutritional management essential.

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1. Risk of Micronutrient Deficiency in CKD Patients

CKD patients face significant challenges in maintaining adequate micronutrient levels due to dietary restrictions, dialysis-related losses, and impaired nutrient absorption.

Major Causes of Deficiency

(1) Dietary Restrictions

• Control of phosphorus (P), potassium (K), and sodium (Na) intake often leads to reduced consumption of fruits, vegetables, dairy, and high-protein foods, increasing the risk of micronutrient deficiencies.

(2) Reduced Kidney Activation of Certain Nutrients

• Vitamin D activation decreases → Calcium absorption declines, increasing the risk of osteoporosis.
• Erythropoietin (EPO) production declines → Iron utilization is impaired, contributing to anemia.

(3) Losses Due to Hemodialysis

• Water-soluble vitamins (B-complex, C) and some minerals (iron, zinc, magnesium) are lost during dialysis.

Micronutrients Most at Risk of Deficiency

Nutrient	Cause of Deficiency	Symptoms of Deficiency
Vitamin D	Reduced activation by kidneys	Poor bone health, fracture risk
Vitamin B-complex (B1, B6, B12, folate)	Loss during dialysis	Anemia, neuropathy, fatigue
Vitamin C	Loss during dialysis	Weak immunity, fatigue
Iron (Fe)	Decreased absorption, dialysis loss	Anemia, dizziness, fatigue
Zinc (Zn)	Loss during dialysis	Poor immune function, taste alteration
Magnesium (Mg)	Partial loss in dialysis	Muscle cramps, arrhythmia

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2. Risks of Micronutrient Overconsumption in CKD Patients

With kidney dysfunction, some micronutrients accumulate in the body, leading to toxicity and severe complications.

Nutrients to Watch Out for & Associated Risks

Nutrient	Risk of Overconsumption
Potassium (K)	Hyperkalemia (arrhythmias, cardiac arrest)
Phosphorus (P)	Vascular calcification, osteoporosis
Vitamin A	Liver damage, vision impairment
Vitamin C	Excess oxalate formation, kidney stone risk
Magnesium (Mg)	Arrhythmias, muscle weakness

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3. Causes of Micronutrient Loss During Hemodialysis

(1) How Nutrients Are Lost in Dialysis

Diffusion Process

• Water-soluble vitamins (B-complex, C) and small minerals (iron, zinc, magnesium) diffuse into dialysis fluid, leading to gradual depletion.

Dialysate Exchange Process

• Peritoneal dialysis (PD) involves continuous dialysate exchange, causing gradual loss of vitamins and minerals over time.

Blood Dilution Effect

• Temporary changes in blood volume during dialysis can dilute nutrient levels, contributing to further depletion.

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4. Nutritional Supplementation Guide for CKD Patients

💡 Taking supplements indiscriminately can be dangerous. Consult a healthcare provider before supplementation.

✅ When to Supplement

• Confirmed deficiency based on blood tests
• Possible supplementation for vitamin D, iron, B-complex vitamins, folate, and zinc

🚫 Supplements to Avoid

• Regular multivitamins containing vitamin A, potassium, phosphorus, or magnesium
• High-dose vitamin C supplements (risk of kidney stones)
• Potassium-containing supplements

Real-Life Case Study

Mr. Kim (65, hemodialysis patient) was taking a regular multivitamin but developed arrhythmia due to potassium overload. After switching to a dialysis-specific vitamin supplement, his condition stabilized.

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5. Conclusion

• CKD patients must carefully manage both micronutrient deficiencies and overconsumption.
• Essential nutrients (iron, vitamin D, B-complex) should be supplemented if deficient, while excessive intake of certain nutrients (potassium, phosphorus, vitamin A) must be avoided.
• Regular blood tests are crucial to assess micronutrient status and guide supplementation.

✏️ Always consult a healthcare provider before choosing multivitamins or individual supplements!

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Hemodialysis Patients & Vitamin Supplementation: Why Take Vitamins After Dialysis?

1. Why Post-Dialysis Vitamin Intake Is Ideal

(1) Replenishing Water-Soluble Vitamin Losses

• Hemodialysis removes water-soluble vitamins (B1, B6, B12, folate, vitamin C), so taking them immediately after dialysis helps restore levels efficiently.
• If taken before or during dialysis, some vitamins may be lost in dialysis fluid, reducing effectiveness.

(2) Improved Absorption with Post-Dialysis Meal

• B-complex vitamins and iron are better absorbed when taken with food.
• Since post-dialysis is often mealtime, taking vitamins at this time enhances nutrient absorption.

(3) Maximizing Vitamin D & Iron Utilization

• Vitamin D is fat-soluble, meaning it is best absorbed when taken with food.
• Iron supplements are better tolerated and absorbed after meals, reducing the risk of gastrointestinal discomfort.

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2. Comparing Vitamin Intake Timing: Pre-Dialysis, During, or Post-Dialysis?

Timing	Advantages	Disadvantages
Before dialysis	Allows time for nutrient absorption	Water-soluble vitamins may be lost during dialysis
During dialysis	Continuous supplementation possible	Many nutrients are removed with dialysis fluid
After dialysis (Recommended)	Replenishes lost nutrients immediately Enhances absorption with food	No significant disadvantages

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3. Additional Tips for Vitamin Supplementation

✅ Recommended Practices
✔ Take vitamins immediately after dialysis with food
✔ Use dialysis-specific vitamin formulations (avoid regular multivitamins)
✔ Only supplement nutrients confirmed as deficient (avoid excess intake)

🚫 What to Avoid
✖ Taking vitamins before dialysis (risk of nutrient loss)
✖ Multivitamins containing excess potassium, phosphorus, or vitamin A
✖ High-dose vitamin C supplements (kidney stone risk)

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Reference

Allen, L. H. (2025). Micronutrients — Assessment, Requirements, Deficiencies, and Interventions. The New England Journal of Medicine, 392(10), 1006-1016. DOI: 10.1056/NEJMra2314150.