Along with hormones secreted by your thyroid and parathyroid glands, vitamin D helps your body regulate its levels of the mineral calcium. If you take too much supplemental vitamin D, you can trigger a condition called hypercalcemia, which occurs when your hormone balance is altered and you develop abnormally high calcium levels in your bloodstream, according to PubMed Health.
Basics
While the vast majority of your body's calcium supply is stored in your bones, a small amount also circulates in your bloodstream. You need this calcium to help regulate the widening and narrowing of your blood vessels, secrete hormones and send certain signals to your cells and nerves. Normally, a hormone from the parathyroid glands in your neck increases your blood calcium levels when they fall too low, while a hormone from your thyroid gland --- also in your neck --- lowers your levels when they rise too high. People with hypercalcemia lose the ability to properly reduce excessive blood calcium.
Excessive Vitamin D Intake
If you take too many vitamin D supplements, you can potentially develop vitamin D toxicity, a condition also known as hypervitaminosis D, according to MayoClinic.com. The primary result of this condition is the onset of hypercalcemia. Most people who take vitamin D have fairly low risks for the onset of hypervitaminosis. Underlying circumstances that can increase your risks include use of certain diuretic medications and the presence of kidney or liver problems. Vitamin D from food sources or sunlight does not typically trigger any problems related to vitamin toxicity.
Symptoms
Hypercalcemia can trigger significant problems throughout your body. Potential kidney-related symptoms of hypercalcemia include pain in your side, abnormally frequent urination and abnormally frequent thirst. Abdominal symptoms of the disorder include nausea, vomiting, pain and constipation. Bone-related symptoms may include pain, abnormal curvature of your spine, disease-related fractures, shoulder bowing and reduction of your normal height. Mental symptoms can include depression, memory loss, dementia, irritability and apathy. And muscle-related symptoms of hypercalcemia include weakness and abnormal muscle twitches.
Treatment and Considerations
Treatments for hypervitaminosis D include halting your intake of supplemental vitamin D and controlling your intake of calcium. If excessive vitamin D triggers severe hypercalcemia, you may also require hospitalization and treatment with a combination of hormones, medication and the artificial kidney-cleansing procedure called dialysis. Children and adults age 70 or younger need an overall daily vitamin D intake of 600 IU. Adults over 70 need a daily intake of 800 IU. Most cases of hypervitaminosis occur in people who take at least 10,000 to 40,000 IU of the vitamin per day, according to the Office of Dietary Supplements. If you have concerns about your vitamin D intake, consult your doctor for advice.
References
- PubMed Health: Hypercalcemia
- Office of Dietary Supplements - National Institutes of Health: Dietary Supplement Fact Sheet; Calcium
- MayoClinic.com: Hypercalcemia; Causes; May 29, 2009
- MayoClinic.com: Vitamin Toxicity; What If You Get Too Much?; Katherine Zeratsky, R.D., L.D.; December 11, 2010
- Office of Dietary Supplements - National Institutes of Health: Dietary Supplement Fact Sheet; Vitamin D
