Vitamin D Side Effects: What if You Take too Much of Vitamin D?

No doubt vitamin D is crucial for a good health, especially for strong bones. However, excess amount of vitamin D in your body could really impair your health. It’s very hard to recognize its overdose unless you get your 25 (OH) D level tested, simply because its symptoms are similar to that of many other diseases.


How Does It Happen?

Since our body has an inbuilt mechanism to control the amount of vitamin D it synthesizes through exposure to sunlight, the risk of vitamin D overdose is not possible due to sun exposure. Even consuming food substances rich in vitamin D cannot cause vitamin D toxicity unless you take large amounts of cod liver oil every day. It is very likely to occur from higher intake of supplemental vitamin D, hence, do not consider taking vitamin D supplements without the supervision of a nutritionist or doctor.


Symptoms of Vitamin D Overdose

Too much of vitamin D raises the blood level of calcium, resulting into hypercalcaemia which leads to over calcification of tissues such as heart, lungs, kidney and blood vessels. Deposition of calcium impairs the function of soft tissues and causes kidney stone which is followed by hypertension. Higher calcium level in blood causes heart murmurs, heart rhythm defects and eventually heart attack.

These are the severe symptoms therefore are not observed in the beginning. Immediate indications of vitamin D toxicity include excessive thirst, nausea, vomiting, fatigue, abdominal cramps and loss of appetite. It doesn’t happen in a day, vitamin D toxicity takes anywhere between several days to a few weeks before the symptoms are observed.

It affects not only your physical health, your mental status is also at risk. The victims of overdose develop mental retardation, disorientation and confusion.

If you have been taking vitamin D supplements and feel any of these symptoms, seek medical help as soon as possible. Consult a nutritionist first in case you want to start on a course of supplements.


How Much Vitamin D is Appropriate for You?

Your age is the key factor in determining the amount of vitamin D you need each day. The Food and Nutrition Board (FNB) recommends the following daily intake for dietary vitamin D:


Age (years)





400 IU

400 IU



600 IU

600 IU



600 IU

600 IU

600 IU


600 IU

600 IU



800 IU

800 IU


IU = International units.


Though the table above demonstrates the recommend daily intake, nothing would happen if your intake is slightly higher than this. Because the safe upper limit for adults is 2000 IU, and toxicity is caused in children if their sustained daily intake goes higher than 1000 IU.



Are you considering taking vitamin D supplements? Don’t, if you are suffering from one of the following diseases:

  • Kidney problems
  • Heart Diseases
  • High levels of calcium or phosphorus in blood


When under the course of thiazide diuretics, you should not take vitamin D supplements unless under a medical supervision because their combined effect may increase the calcium levels in the body.

Certain medications such as atorvastatin, digoxin, corticosteroids, calcium channel blockers, phenitoin, isoniazid and rifampin interfere with the activities of vitamin D.


Treatment of Vitamin D Overdose

In case you are diagnosed with vitamin D toxicity, seek the help of an experienced health practitioner and request him to start the treatment as soon as possible. The treatment includes:

  • Stopping vitamin D supplements
  • Restricting the intake of calcium
  • Rehydration
  • Total sun avoidance


Treatments may take several months before vitamin D level is back into the normal range.





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