The Risks of Vitamin D Overdose

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Vitamin D is essential for your overall health and especially for the development of strong bones and teeth. According to Reinhold Veith, writing in the Journal of Nutritional and Environmental Medicine, adequate intake of vitamin D leads to the reduction in the incidences of breast, prostate and bowel cancers.

Nutrition experts say that the body needs a very low dose of vitamin D for it to function efficiently. You don’t even have to consume foods that contain vitamin D to get your daily intake. All you have to do is expose yourself to sunlight for up to 15 minutes daily, about t thrice a week to get the necessary vitamin D for your body.

However, excessive vitamin D in your body could lead to it turning toxic and impairing your health.

In practice, it’s really rare for a person to end up with an overdose of vitamin D. This is because once the body’s requirement of vitamin D is met, the body shuts down the process further absorption of it.

So, if you’re worried about overconsuming foods that contain vitamin D, put the worry aside. Studies have shown that overconsumption of foods rich in vitamin D does not lead to an overdose of vitamin D. The only food that you should be careful about not overconsuming is cod liver oil. Similarly, you don’t have to worry about overexposure to sunlight.

Likely Cause of Vitamin D Overdose

While it’s difficult to end up with a vitamin D overdose through the foods that you consume, overdose is still possible from overconsumption of vitamin D supplements.

It was mentioned earlier that the body shuts down the absorption process of vitamin D when the limit is reached. However, this is not the case when it comes to vitamin D supplements.

The mechanism does not simply work when vitamin D supplements are over consumed. So, vitamin D in the body reaches a toxic level and results in a condition called Hypervitaminosis D. The condition exists because the body doesn’t excrete excess vitamin D from the body. Instead, the excess is stored away in the fat cells and accumulates until it reach a dangerous level.

Most at risk of vitamin D overdose are those with rickets or who are suffering from others conditions that need a prescription of vitamin D supplements. Even then, overdose of vitamin D does not happen overnight.

The National Institutes of Health recommends the daily adequate intake for vitamin D .

  • From Birth to 50 years– 5 mcg, about 200 IU
  • 51 to 70 years - 10 mcg, about 400 IU
  • 71 years and above - 15mcg, about 600IU

Even if this daily requirement is exceeded several times over, it doesn’t lead to toxicity. Babies under 12 months would have to take a sustained intake of 1000 mcg for toxicity to result in one to 4 months. As for adults, 2500 mcg of vitamin D, would result in toxicity in one to four months.

From the above, we could see that it’s quite difficult to end up with vitamin D overdose unless there’s an uncontrolled consumption of vitamin D supplements.

Vitamin D Overdose Health Risks

Excessive intake of vitamin D could lead to:

  • High levels of calcium in your body
  • Large deposits of calcium and phosphate in lung, heart and kidney tissues which could lead to irreversible organ malfunction
  • Kidney stones and possible renal failure
  • Poor appetite, nausea and loss of weight
  • High blood pressure and risk of heart disease
  • Pregnant women with an overdose of Vitamin D run the risk of giving birth to babies physically or mentally retarded

Other symptoms of vitamin D overdose include bone pain, excessive thirst and dehydration, itchy skin, muscular weakness and fatigue and severe headache among others.

Seek medical help if you’re taking vitamin D supplements and are experiencing any of the above symptoms. Also, consult a doctor before starting on a course of vitamin D supplements. Always stick to your doctor’s prescription to minimize the risk of vitamin D overdose.


Vitamin D Nutrition and its Potential Health Benefits for Bone, Cancer and Other Conditions, Reinhold Vieth, Journal of Nutritional and Environmental Medicine - National Institutes of Health on adequate daily intake of vitamin D - General information on vitamin D overdose