8 Side Effects of Too Much Vitamin D That Can Be Dangerous

8 Side Effects of Too Much Vitamin D That Can Be Dangerous

Vitamins are important for the growth of your body and in maintaining your overall health. But it is also true that anything that is taken in excess cannot be tolerated by your body and can have an adverse effect on it. The same is with Vitamin D.

Vitamin D is a prime nutrient as it helps your body to absorb dietary calcium, development of your muscle cells, proper functioning of the innate and adaptive immune system, maintenance of the health of your skeletal system, and many more so that you can have strong, healthy bones. But it is also possible that consumption of too much vitamin D can have adverse effects on your body.

These side effects are referred to as Vitamin D toxicity. Hence, it is important to understand about these especially if you are consuming Vitamin D supplements. Thankfully for you, in this blog, we will be discussing about all the side effects related to Vitamin D.

Signs you’re taking too much vitamin D

Signs youre taking too much vitamin D

As said consumption of too much vitamin D can have adverse effects on your body. These side effects are referred to as Vitamin D toxicity. Although, it is rare to exceed your vitamin D needs, is it better to know when you have exceeded them so here are the symptoms to know it. If you are regularly experiencing two or more of the symptoms listed below, it is better to consult your doctor about testing your vitamin D levels. So that you can adjust your daily supplement dose of vitamin D.

  • Excessive fatigue
  • Change in your skin tone
  • Loss of appetite
  • Constant headache
  • Nausea and vomiting
  • Constipation
  • Increased thirst
  • Weakness of muscles

Understanding vitamin D toxicity

Vitamin D toxicity is also known as hypervitaminosis D, vitamin D toxicity is rare and occurs when your body’s vitamin D levels are too high. Vitamin D toxicity typically develops from over-supplementation, as opposed to diet or sun exposure.

Because when your body consumes vitamin D through the sun, your body will be able to regulate the amount of natural vitamin D that is produced. Also, when it comes to food, naturally-occurring vitamin D is not common and fortified foods do not usually contain enough levels of vitamin D to lead to toxicity.

Possible Side effects of Vitamin D

1. Elevated blood levels

Blood vitamin D levels are defined as Hypervitaminosis D, if it is over 100 ng per ml, while vitamin D intoxication is defined as serum levels over 150 ng per ml. For vitamin D to exceed the limit and reach dangerous levels in the body, it needs to exceed 100 nanograms per ml. Although it is true that toxicity is rare but you can always maintain it if you keep your daily intake levels below 10,000 IU per day and lower or stop taking high doses of vitamin D supplements, experts recommend that people with typical vitamin D levels do not exceed 4,000 IU of vitamin D per day (R).

Suggestions of vitamin D levels may vary, as research suggests that levels between 30–60 ng/ml are likely effective for protecting against any type of illness and disease. Even when taking high-dose vitamin D supplements, it’s unlikely that a healthy person’s blood vitamin D levels would come close to reaching excessive or toxic levels.

One needs to understand that people who have a deficiency in vitamin D, those people typically need to take much higher levels of vitamin D dose than the current Tolerable Upper Intake Level (UL) of 4,000 IU per day to reach and maintain an adequate amount of vitamin D levels.

However, make sure to consult a healthcare professional on what dosage you should take. This will help you avoid dangerous dosing and take proper care.

2. Elevated blood calcium levels

Do you know that the most important role of vitamin D is to absorb calcium from the food you consume? Yes and that is why it is said that vitamin D is necessary for bone health. But if your vitamin D intake is high, your blood calcium levels will also be high and it may reach levels that can cause discomfort and significantly dangerous symptoms.

The symptoms of vitamin D toxicity are primarily related to hypercalcemia, which means excessively high blood calcium levels (R). The relationship between vitamin D and calcium is very strong. When there are high levels of vitamin D in the blood, the number of calcium increases, and that is absorbed by the intestines. High levels of vitamin D in the blood can also release calcium from the bones into your bloodstream.

Symptoms of hypercalcemia include:

  • Discomfort and indigestion may lead to vomiting, nausea, constipation, and stomach pain
  • You may feel fatigued, dizziness, hallucinations, and confusion
  • Kidney stones, kidney injury, and even kidney failure
  • Increase in blood pressure and heart abnormalities
  • Loss of appetite
  • Excessive urination
  • Unexplained exhaustion
  • A metallic taste in the mouth
  • Irregular heartbeat
  • Dehydration

So you may be thinking what is the normal range of blood calcium? to answer it is 8.5–10.8 mg/dL (R). Hypercalcemia typically develops after people consume a very high amount of vitamin D for a longer time. Hypercalcemia can be dangerous and life-threatening, one may require immediate medical attention.

3.Inflammation of the Pancreas

Inflammation of the pancreas is the term for severe pancreatitis that is caused by Hypercalcemia.

Signs of pancreatitis include:

  • Stomach pain in the upper side that extends to the back
  • Weight loss
  • Nausea and vomiting
  • Fever
  • A rapid pulse

4.Gastrointestinal symptoms

The excessive amount of calcium in the blood is related to one of the main side effects of excessive vitamin D levels are related to (R).

Some of the main symptoms of hypercalcemia include:

  • Nausea
  • Vomiting
  • Constipation
  • Diarrhea
  • Poor Appetite

Taking large doses of vitamin D can also mess up your gut and these can be the signs of other health issues as well, therefore it is important to inform your doctor if you are taking any supplements. Although, everyone may not experience all of these symptoms related to hypercalcemia and may not be the same for everyone.

5.Irregular heartbeat and heart attack

In people who face severe hypercalcemia, the function of their hearts cell can reduce or change the ability of the heart function. Also, irregularities in the heartbeat of people with severe hypercalcemia were often experienced. A person with severely high levels of calcium or phosphate in the blood may also develop calcium deposits, or plaques, in the arteries or valves of the heart.

Some signs of heart complications associated with vitamin D toxicity include:

  • The irregular heartbeat can be continuous or temporary
  • Dizziness
  • Chest Pain
  • Sudden exhaustion
  • High blood pressure
  • Fatigue
  • Pain when exercising
  • Chest pain

In 2012, a case study was done and it was reported that (R) the case of a 70-year-old woman who received calcium injections in the equivalent of 80,000 IU per day for over 30 days. Her symptoms were hypercalcemia and complete heart blockage, thus she required a permanent pacemaker.

6.Altered mental status

People who have vitamin D toxicity because of hypercalcemia can lead to altered mental status in them. People with vitamin D toxicity commonly have experienced symptoms like confusion, depression, and psychosis. In fact, in extreme cases, coma has been reported (R).

In some cases, vitamin D toxicity can result in kidney issues, like kidney failure, blockage, and even kidney injury. That is because having too much vitamin D in the body can lead to high levels of calcium, through too much urination and calcification of the kidneys, which may lead to water loss (R).

Hypercalcemia which leads to decreased kidney function can also cause the blood vessels of the kidneys to restrict, (R). In fact, many of the studies have reported moderate-to-severe kidney injury in people who develop vitamin D toxicity (R).

In those people who have kidney disease, a vitamin D deficiency can also harm the kidneys and lead to extreme complications. That’s one reason why maintaining adequate blood levels of vitamin D is crucial for your health (R).

7.Brittle bones and bone pain

The body may not have enough hormones to hold together the mineral to the bones effectively especially when there is too much calcium flowing freely in the bloodstream. Vitamin D toxicity can cause hypercalcemia and similar issues with the bones. Some of these symptoms may include

  • Bones that are prone to fracture or break
  • Aching or painful bones
  • Severe back or joint pain
  • Instability
  • An increased rate of falling
  • Severely stooped posture
  • Loss of height or length of limb

8.Lung damage

Soft tissues get deposited into your body when there are very high levels of calcium and phosphate in the blood that comes together to form crystals. The crystals are especially likely to deposit in soft-tissue organs that act like filters, such as the lungs. These are present in the lungs because of too many of these calcium salt deposits, or ectopic calcifications. Also, they can even impair the organ’s function.

There are some of the symptoms that result in lung damage including Coughing, trouble breathing, and chest pain.

How Much Vitamin D Do You Need?

How much vitamin D do you need

You might be wondering if these are the side effects of consuming too much vitamin D, how much vitamin D is needed which is safe for your body? Well to answer that, there are recommended dietary allowance (RDA) for people in different age groups which we will address below. These recommendations come from the National Academies of Sciences, Engineering, and Medicine.

These recommendations are based on a certain no of factors, however, keep in mind that your healthcare professional may recommend doses that may be higher or lower than what’s listed according to your body’s needs and conditions. Note that the amount of vitamin D in foods and supplements is usually expressed in terms of International Units IU/ day which refers to “International Units per day.”

Below are recommended per day dietary allowance for vitamin D followed by the upper intake level (IU/day)

  • For infants from 0-6 months – 400 IU/day for optimal intake and upper intake level should be of 1,000 IU/day
  • Infants 6-12 months – 400 IU/day for optimal intake and upper intake level should be of the level of 1,500 IU/day
  • Children 1-3 years old – dietary allowance of 600 IU/day for optimal intake and upper intake level should be of 2,500 IU/day
  • Children 4-8 years old – dietary allowance of 600 IU/day for optimal intake and upper intake level should be of 3,000 IU/day
  • People 9-70 years old – dietary allowance of 600 IU/day for optimal intake and upper intake level should be of 4,000 IU/day
  • People over 70 years old – dietary allowance of 800 IU/day for optimal intake and upper intake level should be of 4,000 IU/day
  • Women 14-50 years old who are pregnant or lactating – dietary allowance of 600 IU/day for optimal intake and upper intake level should be of 4,000 IU/day

In some cases, healthcare professionals may prescribe higher doses to treat a vitamin D deficiency, although these units provide a good guideline. That is why talk to your healthcare professional to understand what amount of vitamin D intake they recommend for you and what works best for your body.

How common are the side effects of Vitamin D?

The rate of adverse side effects is relatively low even though many people take high doses of vitamin D supplements, and However, long-term or too much consumption of vitamin D in supplements or foods can cause adverse effects on your body.

Your body stores vitamin D in fat tissues, and it can take weeks or months for the effects of vitamin D toxicity to fully wear off. However, there are some prescription formulas that contain a combination of vitamin D and calcitriol. A person with vitamin D toxicity that uses this combination to consume is said to recover within a few days which is reported by the studies (R)because calcitriol benefits in breaking down quickly in the body.


Vitamin D toxicity can lead to severe symptoms in your body. If a person has consumed supplements for a very long duration and has taken in excessive amounts, they have a higher risk of experiencing toxicity. This can result in vitamin D to build up in the blood.

The risk of experiencing adverse side effects after absorbing vitamin D from the diet or exposure to the sun is very low compared to the supplements. Also, always take help from your doctor to guide you on this. Hope this article has helped you in understanding the side effects of Vitamin D.

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