Nephrologist Borja Quiroga on Vitamin D: "I've seen people come in with kidney stones."

The consumption of nutritional supplements such as vitamin D has grown significantly in recent years. In Spain , more and more people are incorporating them into their diet without medical supervision . This trend worries professionals like nephrologist Borja Quiroga , who warns of the real risks of their indiscriminate use.

In an interview with La Vanguardia , Quiroga issued a direct warning: "I've seen people who have come in with kidney stones." He explains that vitamin D promotes calcium absorption , which can cause kidney stones if taken without medical reason. He has also treated cases of poisoning and kidney failure due to excess intake of this vitamin in healthy people.

Unjustified use and lack of scientific evidence

Quiroga complains that supplements are prescribed without adequately assessing the patient's prior health. He only recommends vitamin D in specific cases such as osteoporosis or kidney disease . He asserts that it "does not improve cardiovascular risk, reduce tumors, or prevent fractures" in healthy people. He also criticizes the trend of supplementing children: "There is no scientific justification," he states.

Creatine, the supplement that is approved

Although critical of most supplements, Quiroga supports the use of creatine monohydrate , which he describes as safe and effective . He notes that it was misunderstood for years due to its similarity to creatinine , but that studies have ruled out any kidney damage. Its usefulness is even being investigated in patients with Alzheimer's , which, he says, reinforces its clinical value.

The specialist recommends always choosing pure creatine monohydrate with a seal of quality , such as Creapure . He warns against unreliable products, especially those sold in certain gyms. " Not everything sold is controlled. You have to read labels carefully and be wary of miracle formulas ," he concludes. For Quiroga, scientific evidence should be the fundamental criterion in any decision about supplementation.