If you take vitamin D, you risk overdosing. This develops gradually and can have serious consequences – kidney stones, for example.
Vitamin D is an essential substance that the body produces itself when the skin is exposed to the sun. If you don’t get enough daylight for months, you can develop a deficiency that damages bone health, among other things. The best way to prevent and counteract this is to get some fresh air every day. If that is not enough, the doctor can prescribe vitamin D as a supplement. It is also recommended for certain risk groups, such as the elderly and infants.
On the other hand, anyone who does not belong to a risk group and swallows vitamin D tablets without a doctor’s recommendation is not doing their health any good. On the contrary: an overdose of vitamin D can have a number of undesirable consequences.
Why can vitamin D cause kidney stones?
On the one hand, vitamin D causes the intestines to absorb more calcium and, on the other hand, the kidneys excrete less calcium. Over time, the calcium level rises to an unhealthy level, which can lead to various symptoms – such as nausea and vomiting, stomach ache, loss of appetite, constipation, tiredness, cardiac arrhythmia and muscle weakness.
The excess calcium also damages the kidneys: it can solidify and form crystals a few millimeters in size – so-called kidney stones. In rare cases, the kidneys are even damaged to such an extent that they can no longer fulfill their function.
Kidney stones caused by vitamin D – what are possible warning signs?
A vitamin D excess develops insidiously and usually causes symptoms at a late stage. At the beginning, there are usually nausea and vomiting, stomachache, loss of appetite and constipation, i.e. those symptoms that can be attributed to the excessively high calcium level caused by vitamin D.
If kidney stones have formed, they do not necessarily show up as symptoms at first. The stones usually only cause noticeable symptoms when they block the renal pelvis or leave the kidney and migrate through the ureter. Those affected then typically suffer from cramping pains in the lower abdomen, stomach or back.
If you experience such symptoms after taking vitamin D for a long time, you should have them checked out by a doctor as soon as possible. If there is actually an excess of calcium caused by vitamin D, the doctor can take measures to eliminate it. In addition, she or he can assess what treatment is necessary to get the consequences under control.
In the case of kidney stones, the appropriate therapy depends on the size and location of the stones and the extent of the pain. You can find out more about treating kidney stones in our article “Kidney stones – what to do now”.