The human organism converts vitamin D into calcidiol and then “stores” it for up to 29 days. To diagnose vitamin D overdose, a blood test is used to measure serum levels of calcidiol. However, patients keep in mind that the side effects of the increased dose only occur when large amounts of cholecalciferol are taken. For example, excessive consumption of the calciol increases the likelihood that consumers will suffer mineral deficiencies. There is also a risk of premature calcification.
What happens during a vitamin D overdose?
Vitamin D3, called cholecalciferol in technical language, is not a common vitamin. The reason is that the human organism is capable of synthesizing the calciol itself under the influence of ultraviolet B rays. In order for this to succeed, patients spend up to twenty minutes a day in the sun. In the winter time, there is no possibility for the body to produce vitamin D3 on its own due to the shallow incidence of the sun’s rays.
To prevent a deficiency, consumers take preparations containing cholecalciferol.
Here, medical experts recommend not to exceed the daily requirement of calciol. Otherwise, vitamin D overdose occurs, which brings with it numerous side effects. These include, for example, mild to severe symptoms of poisoning.
Diagnosis of vitamin D overdose
Serum levels in healthy people range from 32 to 70 nanograms per milliliter of blood. In the case of vitamin D overdose, the concentration of calcidiol in the bloodstream is up to 15 times higher. The detection of an increased vitamin D content leads to an immediate reduction or complete discontinuation of the supplementary preparations. If side effects or sequelae occur, the treating physicians will start a counter-treatment.
What are the side effects associated with overdose?
The organism needs the vitamin D3 to absorb the calcium from the food. As a result, vitamin D overdose leads to excessive absorption of the mineral. In medicine, this health complication is called hypercalcemia. This effect threatens affected patients with health risks that, in the worst case, prove irreparable. However, the phenomenon only occurs when vitamin D overdoses reach 40,000 International Units per day.
If consumers take medium to high doses of the preparations daily – for example, up to 10,000 International Units – no characteristics of hypercalcemia exist. This is documented by Vieth R in his study: “Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety”. The publication appeared in May 1999. However, if the patients suffer from vitamin D overdose, which is accompanied by the excessive calcium content in the blood, there is an equal threat of hypercalcuria. The medical term refers to the increased excretion of the mineral through the urine.
In the worst case, this leads to the formation of kidney stones or calcifications in the organs. Furthermore, the increased concentration of calcium leads to an increase in blood pressure. Symptoms affecting the stomach and intestines (gastrointestinal) manifest themselves in the form of vomiting, nausea and loss of appetite. If gastrointestinal symptoms are not treated, the side effects spread further.
Excessive production of urine (polyuria) leads to a constant feeling of thirst, itching, nervousness and persistent weakness. The most serious side effect is the complete failure of the kidneys. The circumstance ensures that the body is no longer able to rid itself of toxins.
Complications of short-term vitamin D overdose include:
- Fatigue and weakness
- strong thirst
- loss of appetite
- cardiac arrhythmia
If the symptoms do not appear, the excessive consumption of vitamin D supplements nevertheless leads to hypercalcemia. The resulting damage to organs and vessels entails coronary heart disease, for example. This includes, as an example, myocardial infarction.
Recommended guideline values do not lead to vitamin D overdose
If consumers adhere to the recommended daily requirement of cholecalciferol, they need not fear an overdose. As a rule, medical experts advise a daily intake of 2,000 to 4,000 international units of the calciol. There are no negative consequences if the value is exceeded once. In addition, short-term high doses of up to 60,000 International Units prove to be harmless. For example, consumers take this amount of vitamin D3 to replenish their body stores.
If patients consume this dose over a longer period of time, the likelihood of side effects occurring increases. Primarily during the summer months, individuals who consume 10,000 International Units of the calciol daily may experience critical levels. The reason is that the body also synthesizes cholecalciferol under the influence of UV-B rays from sunlight. In this way, vitamin D overdose occurs.
If users have a calciol level above 70 nanograms per milliliter of blood, calcifications form in the organism even without the hypercalcemia. Furthermore, the high amount of vitamin D3 may lead to a deficiency of other nutrients. These include magnesium, for example.
Does sunlight lead to vitamin D overdose?
If patients allow themselves a long sunbath, they need not fear an overdose of cholecalciferol. Relevant regulatory mechanisms exist in the skin that prevent the excessive production of vitamin D3 under the influence of the sun’s rays. At the maximum, the human organism synthesizes a quantity of calciol corresponding to an intake of 10,000 to 20,000 International Units. In extreme cases, exposure to sunlight leads to vitamin D overdose, which results in increased calcium absorption. The body regulates this by excreting the mineral through urine.
If people spend an excessive amount of time in the sun, kidney stones will form in the long run. This means that the side effects of high vitamin D concentration occur even in the absence of hypercalcemia. For this reason, doctors advise consumers to use the sun with caution.
What happens with a permanent vitamin D overdose?
Sustained excessive intake of vitamin D may further lead to ischemic heart disease. A strongly increased calcium content leads to a reduction in the level of corticosteroids and bisphosphonates in the blood. This reduction in turn promotes damage to vital organs. These include the heart or kidneys.
The concentration of the natural defense cells found in every body decreases in the case of an overdose over a longer period of time. Lay people also refer to the cells as killer cells. As a result, infections have been shown to occur more frequently. In children, for example, the risk of developing rickets increases 13-fold. This also applies to offspring who have not had any similar previous illnesses.
The T-cells become highly relevant for the human immune system. Due to the increased vitamin D content in the blood, there is a suppression of the elements. This is followed by a weakening of the immune defenses. The demonstrable deterioration of the body’s defenses favors the development of inflammatory diseases, osteoporosis, cancers, leukemia and autoimmune diseases.
Vitamin D overdose leads to vitamin K deficiency
If calcifications occur in those affected by calciol overdose without detectable hypercalcemia, the circumstance is based on a functional vitamin K2 deficiency. The substance acquires relevance in transporting the calcium absorbed from food to the target regions. In addition, vitamin K supports the incorporation of the mineral into the bones.
If the important additive is missing in the organism, the calcium is deposited unused in the tissue and leads to the calcification symptoms. If the patients take excessive vitamin D3 without adjusting the vitamin K dose, the functional vitamin K2 deficiency occurs. Therefore, doctors recommend consumers to take cholecalciferol preparations that have vitamin K concentration at the same time.
How much vitamin D can you take in addition?
Children up to the age of 16 need a daily vitamin D intake of 15 to 20 micrograms. Experts advocate a daily dose of 20 micrograms for adolescents and adults and up to 25 micrograms for pregnant women.
After the winter months, more than half of all adults in Germany suffer from a vitamin D deficiency. During this time, sun exposure on the skin is not sufficient to keep the level in the blood within the optimal range. To avoid overdose and thus vitamin D hypervitaminosis, adults do not exceed the dose of 50 micrograms in their daily vitamin D intake.
Vitamin D in food
Vitamin D intake via food plays a subordinate role. The body obtains the majority of the necessary amount of vitamin D via UV-B rays, which the organism converts into the important hormone. Only food supplements make it possible to supply the body with relevant amounts of vitamin D.
Foods with a significant content of vitamin D are of animal origin.
- A chicken egg yolk contains 5.60 micrograms per 100 grams and should therefore be taken into account in vitamin D intake.
- Salmon, with 16 micrograms and mackerel with four micrograms also belong in the diet.
- Margarine has 2.5 to eight micrograms and beef liver 1.7 micrograms per 100 grams of vitamin D.
- Avocados and mushrooms are also among useful foods to control the vitamin D balance
For vegetarians and especially vegans, it is particularly difficult to achieve sufficient vitamin D intake through food. They can compensate for this deficit with longer stays in the sun or by means of vitamin D supplements.
Vitamin D supplements
People who do not frequently expose themselves to the sun have a high risk of developing a vitamin D deficiency. In the dark winter months, the UV-B rays responsible for the formation of the hormone are not sufficient. This circumstance causes the well-known winter depression.
If there is a deficiency of the so-called sun hormone, those affected take calcium supplements in addition to supplementary vitamin D intake. Due to a permanent deficiency of the hormone, calcium levels are also impaired. The blood count does not always provide information about this. The body draws calcium from the bones to maintain the level in the blood as long as possible. This favors the development of osteoporosis.
A deficiency caused by insufficient vitamin D intake can be treated with special supplements. The supplements contain a sufficient amount of the hormone, so that additional exposure to the sun is unnecessary.
Adults would have to expose themselves to the sun for four hours a day. This is hardly feasible for many people today. In this calculation, sun exposure on the hands and face is not enough, but refers to the entire body. Deficiencies do not occur infrequently. Vitamin D intake via supplements requires medical attention. An overdose causes severe adverse health effects.
How quickly does vitamin D work after ingestion?
Vitamin preparations are commercially available everywhere. How quickly does vitamin D have a positive effect on health? Doctors answer this question differently. Therefore, it is advisable to rely on the instructions of professionals. Far more important is to focus on the natural sources of vitamin D supply, as they achieve a better efficiency.
Alarming vitamin D deficiency in Germany and Switzerland
Research into vitamin D has progressed so far that by now no one questions its significant contribution to health. A 2012 study found vitamin D deficiency in half of the Swiss population. Only 50% had the minimum levels of 75 nmol/l. In Germany, the results are similar, with 57% of women and 58% of men having measured levels below the critical threshold.
The deficiency is mainly caused by little time spent outdoors. The sun is the decisive supplier of the vitamin. Those who only work indoors take in insufficient amounts of vitamin D. This can result in various diseases. Patients have various options for vitamin D to take effect quickly.
Ways to compensate for vitamin D deficiency
The following sources are used to absorb vitamin D:
- Food supplement
The main supplier is the sun. Experts recommend exposure to its light for thirty minutes a day. The use of sunscreen prevents the formation of vitamins in the skin. That is why patients refrain from it. The absorption of vitamin D from the sun depends on the person. Skin color, age and weight play a role.
In winter, solar radiation in European latitudes is not sufficient for optimal vitamin D supply. In summer, the body stores surplus amounts, which are used in winter. Overweight people lose the opportunity to store the vitamin. Foods contribute to the supply only to a limited extent. Fatty fish, mushrooms and dairy products contribute to the daily ration. There is a risk of overdose when taking artificial vitamin D supplements. Only the doctor prescribes the right dose depending on the person and medical history.
How quickly does vitamin D work after ingestion?
There is no single answer to this question. Everyone needs vitamin D every day. With 125 to 200 nmol/l vitamin D in the blood, Europeans can survive the winter without any symptoms of deficiency. An intake of 1,000 to 2,000 IU (international units) per day reduces the risk of various diseases such as cancer and multiple sclerosis. Those who pay attention to their vitamin D levels early on are less likely to fall seriously ill. Preventive use during pregnancy has a positive effect on the development of the child.
According to one study, relapses in MS diseases were significantly reduced after six months of vitamin D therapy of 1,000 IU daily. Deficiency in European latitudes often cannot be remedied due to circumstances. Therefore, vitamin D therapies are designed for the long term. Most often, the doctor prescribes a higher initial dose, which he later decreases. The new dosage remains in place for several months.
Those who take preventive care of their vitamin D levels reduce the possibility of getting seriously ill. The sun covers 80 to 90% of the daily requirement. Spending 15 to 30 minutes outdoors makes a decisive contribution to coverage. The ideal duration of stay varies according to the person, taking into account age, weight and skin color. Vitamin D acts quickly against the threat of serious diseases. Stopping taking the vitamin is not a solution. It protects only when its level is constantly at the necessary level.
Overdose after taking vitamin D
In healthy people, the vitamin D content is between 30 and 70 micrograms per liter. An overdose allows the value to be increased by a factor of 15. If the physician determines an overdose by means of a blood test, the affected person reduces the vitamin D intake or stops it completely.
As a consequence of an overdosed vitamin D intake, due to the increased calcium content, high blood pressure develops. Symptoms affecting the gastrointestinal tract are as follows
- Loss of appetite,
- nausea and
The overdosed hormone triggers excessive production of urine, which brings a persistent feeling of thirst, nervousness, itching, as well as a feeling of weakness.
Permanent overdoses cause coronary artery diseases. Vitamin D overdose is also accompanied by too much calcium in the blood. Too much calcium in the blood reduces the level of corticosteroids and bisphosphonates. This leads to damage to vital organs, such as the heart and kidneys.
Natural defense cells of the body decrease when vitamin D intake is permanently overdosed. As a result, the body no longer defends itself adequately against infections. Inflammatory diseases such as autoimmune diseases, cancers and leukemia develop more frequently.
Deficiency of the hormone due to insufficient vitamin D intake has become a common disease. It is advisable to compensate for a deficiency by means of vitamin D preparations under the supervision of a physician. The risk of overdose and its symptoms is too great when self-medicating.
Magnesium deficiency results from vitamin D overdose
An overdose of calciol may lead to a deficiency of magnesium. This mineral is needed by the organism in all conversion steps of vitamin D3 to its active form. If users already suffer from a latent magnesium deficiency, consuming large amounts of cholecalciferol will lead to a dangerous deficiency. This results in a reduced supply of the active calciol. Magnesium deficiency is accompanied by characteristic symptoms. These include dizziness, headaches and palpitations.
As a rule, the supply of magnesium in the German population proves to be sufficient. Therefore, the deficiency symptom occurs only in rare cases. Consumers notice the phenomenon when blood levels do not increase despite the consumption of vitamin D3. The occurrence of side effects also provides information about the functional magnesium deficiency.
Basically, the proper intake of vitamin D supplements does not pose any risk to you. If you take only the daily requirement of cholecalciferol, there is no possibility of an overdose. This only occurs with a continuous consumption of 40,000 to 50,000 international units of the calciol. To avoid this, it is better to pay attention to a healthy vitamin D level, which is between 30 and 50 nanograms per milliliter of blood.
If you suffer from a vitamin D3 deficiency, an initial therapy with an intake of 60,000 International Units proves useful to fill the body’s own store. To avoid damage to your health, carry this out under medical supervision. From a daily consumption of 1,000 International Units of vitamin D, ensure that your vitamin K intake is equalized. As soon as you notice that the vitamin D level proves to be low despite the calciol preparations, check the concentration of magnesium in the blood.