Chennai Nephrologist Warns: Vitamin D Overdose Can Damage Your Kidneys

Vitamin D is essential for maintaining healthy bones, teeth, and immune function. However, excessive intake can lead to severe health issues, particularly kidney damage. Dr. Navinath M, a nephrologist and renal transplant physician from Chennai's Asian Institute of Nephrology and Urology, cautioned that the popularity of vitamin D supplements can lead to overdose.

Dr. Navinath emphasized that while vitamin D is beneficial, it can be detrimental if consumed in excess. He advises that supplements should only be taken under medical supervision, as sometimes, less is more in health.

Recommended Daily Intake

The body generally requires only a small daily dose of vitamin D, typically between 400 to 1,000 IU for adults. Consuming more than 4,000 IU daily, especially doses between 8,000 to 12,000 IU over long periods, can lead to toxicity.

Common causes of high vitamin D levels include mistakenly taking high-dose capsules intended for weekly use on a daily basis. Excessive vitamin D results in the body retaining too much calcium—a condition known as hypercalcemia—which places a strain on the kidneys.

Effects on Kidney Health

Long-term filtering of excess calcium can cause kidney tissue damage, potentially leading to kidney stones or nephrocalcinosis. This overload can impair kidney function, resulting in acute kidney injury or irreversible kidney failure.

Symptoms of Overdose

Vitamin D overdose may not present immediate symptoms. However, when they do occur, they may include:

• Nausea and vomiting
• Persistent thirst
• Increased urination
• Muscle weakness
• Confusion or fatigue
• Lower back or side pain (kidney pain)

Severe kidney damage may lead to additional symptoms, such as swelling in the legs, fatigue, and difficulty breathing.

Preventing Overdose

Dr. Navinath stresses the importance of using vitamin D supplements responsibly:

• Only use vitamin D when prescribed by a healthcare provider.
• Never exceed recommended doses.
• Regular blood tests are crucial for monitoring vitamin D and calcium levels, especially for long-term supplement users.

Consult a healthcare professional if you have concerns regarding vitamin D or kidney health.