Vitamin D Overdose Can Fill Kidneys With Stones, Expert Warns

Kidneys filled with stones and cases of kidney failure are the alarming consequences of excessive vitamin D supplementation, according to Spanish nephrologist Borja Quiroga. The specialist has warned against the indiscriminate use of the popular supplement, stating he has personally treated patients who suffered severe kidney damage after taking it without a genuine medical need.

Quiroga explained, as reported by La Vanguardia, that while vitamin D helps the body absorb calcium, dangerously high levels can lead to kidney stone formation. “I have seen people arrive with their kidneys full of stones because of this supplement,” he said.

Widespread Use Among Europeans

The warning comes as dietary supplements have become extremely common across Europe. An Ipsos study found that 88% of Europeans have taken some form of supplement in their lifetime, with vitamin D topping the list as the most widely used.

Quiroga stressed that the vitamin is only beneficial for specific groups, such as those with osteoporosis, where its effectiveness has been proven. However, he emphasized that giving it to healthy people on a broad scale “has not shown any real benefit” in major clinical trials, whether regarding heart disease, cancer prevention, or reducing fractures.

The specialist also criticized the widespread practice of giving vitamin D supplements to children without medical justification, calling it “frightening and illogical.”

Poisoning and Kidney Failure

Quiroga noted he has dealt with cases of toxicity from taking the vitamin without a prescription, which led to kidney failure in some patients. “We use a supplement with the aim of improving health, and then it ends up causing a more serious disease,” he added.

In contrast, the nephrologist considers creatine to be one of the best available supplements. He dismissed the old belief that it harms the kidneys, explaining that a slight rise in creatinine levels does not indicate kidney dysfunction.