Vitamin D: These consequences may have an overdose

Vitamin-D is important for the bones. But an overdose of the sun hormone can have serious consequences. What you have to consider when taking supposedly harmless vitamin D supplements.

As vitamin D strengthens, among other things, the bones, a deficiency can lead to osteoporosis. To prevent this from happening, many people turn to dietary supplements with vitamin D. But taking too much of the vitamin can be detrimental to your health. This is what the Drug Commission of the German Medical Association (AkdÄ) refers to on the basis of two case studies.

A 78-year-old patient and a 60-year-old patient had taken vitamin D supplements on their own - in excessively high doses. This had led to acute kidney failure with pronounced hypercalcemia (too much calcium in the blood), as the AkdÄ writes.


Symptoms of vitamin D overdose

Symptoms of a short-term vitamin D overdose may be:

a headache
Tiredness and exhaustion
Nausea and vomiting
Diarrhea or constipation
strong thirst
Arrhythmia

he symptoms of long-term vitamin D overdose are more serious. Excess calcium can accumulate in blood vessels and kidneys and lead to serious kidney disease. Symptoms range from severe kidney stones to kidney failure.

According to the AkdÄ, the condition of the 78-year-olds has improved after medical treatment and after the administration of cortisone, but the 60-year-old patient has developed serious complications and is now dependent on dialysis.

Avoid vitamin D overdose

Both patients had ordered the preparations on the Internet. The woman had taken 10,000 International Units (IU) of vitamin D3 daily, the man 50,000 IU of vitamin D per day. However, it is usually enough to take 800 IU per day if the body does not produce enough vitamin D itself. A safe upper limit is 4000 IU per day for adolescents and adults, informs the AkdÄ.

Higher dosages of vitamin D should always be discussed with a doctor or pharmacist and should only be done under medical supervision, the Drug Commission emphasizes. From a daily dose of more than 1000 IU, preparations containing vitamin D are also subject to prescription in Germany. "Because of the risks mentioned, we advise against taking high-dose vitamin D supplements on their own," warns AkdÄ.

No vitamin D overdose by food

The human body produces most of its vitamin D needs in the skin itself. This happens especially in the summer months, as this requires UV-B radiation, ie sunlight. A vitamin D overdose by staying too long in the sun is not possible because the body regulates the production of the vitamin itself.

Also by the food intake a vitamin D overdose is not possible. The concentration of the vitamin is too low even in vitamin D-rich foods such as high-fat fish.