Vitamin D Overdose: What Consequences Can It Have?
Vitamin D is extremely popular as a dietary supplement. Many people also believe that it cannot be overdosed. But that’s not true. A vitamin D overdose can even have serious consequences.
Vitamin D is important for muscles, immune system and bones. A deficiency can have a variety of health consequences. According to studies, a vitamin D deficiency threatens osteoporosis and a weakened immune system. A connection between multiple sclerosis and a vitamin D deficiency has now also been established. To prevent disease, so many people resort to dietary supplements with vitamin D. However, if too much of the vitamin is consumed, it can be harmful to health.
However, there is usually only a risk of overdosing with excessive intake of vitamin D supplements. The consequences of such a vitamin D overdose can then be the formation of kidney stones or calcification of the kidneys. Other side effects include nausea, vomiting, tiredness and headache. In extreme cases, an overdose can even be fatal.
Canadians took up to 12,000 IU of vitamin D daily
For example, the case of a 54-year-old Canadian whose disease progression was published in the “Canadian Medical Association Journal (CMAJ)” became known. During his vacation in Southeast Asia, the man had been in the sun for over six to eight hours a day – for over two weeks. Back home, his doctor found kidney problems and increased creatinine levels. He initially suspected that a severe loss of fluids could be the cause of the kidney problems.
When the kidney values did not improve for weeks, doctors in a specialist clinic discovered that the patient’s blood also contained too much calcium. Eventually, the patient explained that a naturopath had prescribed high doses of vitamin D for him. In addition to this drug, the Canadian took another preparation that contained vitamin D. Every day he got 8,000 to 12,000 IU of vitamin D – and that for two and a half years. He had never been diagnosed with vitamin D deficiency before.
4,000 IU of vitamin D per day is the maximum limit
As a rule, an intake of 800 IU per day is enough – and this is only necessary if the body does not produce enough vitamin D itself. The safe upper limit for adolescents and adults is 4,000 IU per day, according to the Drug Commission of the German Medical Association (AkdA).
The Medicines Commission emphasizes that high doses of vitamin D should only be given under medical supervision. From a daily dose of more than 1,000 IU, preparations containing vitamin D require a prescription in Germany.
Sun exposure leads to the body’s own vitamin D production
The human body usually produces most of its vitamin D requirements in the skin, with the help of sunlight. A vitamin D overdose by staying too long in the sun is not possible, as the body regulates the production of the vitamin itself. However, intense UV radiation brings other health risks such as skin cancer with it.
Another source of vitamin D are certain foods such as high-fat fish, liver, eggs, mushrooms, oatmeal or dairy products. Overdosing through food intake is also not possible, since the concentration of vitamin D is too low here.
Taking vitamin K together with vitamin D?
Experts do not yet fully agree on whether vitamin K should always be supplemented when taking vitamin D. Vitamin K makes a significant contribution to the fact that calcium can be built into the bones. However, many medical professionals do not consider supplementation to be necessary because, as a rule, enough vitamin K is presumably absorbed through food.
Nevertheless, there is increasing evidence that an additional dose of vitamin K can improve the effectiveness of vitamin D. In Japan, vitamin K supplements are therefore already among the most frequently prescribed remedies for osteoporosis.
COVID-19 and vitamin D.
In the course of the coronary crisis, the influence of vitamin D on the risk of disease is also being discussed. In fact, studies have found evidence of a link between vitamin D deficiency and severe courses of COVID-19. However, it is unclear whether this means that vitamin D could help at an earlier stage of the disease or even protect it from infection.