- With Mayo Clinic nutritionist
Katherine Zeratsky, R.D., L.D.
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Katherine Zeratsky, R.D., L.D.
Katherine Zeratsky, R.D., L.D.
As a specialty editor for the nutrition and healthy eating guide, Katherine Zeratsky helps you sort through the facts and figures, the fads and the hype to learn more about nutrition and diet.
A Marinette, Wis., native, Katherine is certified in dietetics by the state of Minnesota and the American Dietetic Association. She has been with Mayo Clinic since 1999.
She is active in nutrition-related curriculum and course development in wellness nutrition at Mayo Clinic in Rochester, Minn., and nutrition education related to weight management and practical applications of nutrition-related lifestyle changes.
Other areas of interest include food and nutrition for all life stages, active lifestyles and the culinary arts.
She graduated from the University of Wisconsin-Madison, served a dietetic internship at the University of Iowa Hospitals and Clinics, and worked as a registered dietitian and health risk counselor at ThedaCare of Appleton, Wis., before joining the Mayo Clinic staff.
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Healthy cooking (6)
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Healthy menus and shopping strategies (7)
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Nutritional supplements (16)
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Question
Vitamin D toxicity: What if you get too much?
What is vitamin D toxicity, and should I worry about it since I take supplements?
Answer
from Katherine Zeratsky, R.D., L.D.
Vitamin D toxicity, also called hypervitaminosis D, is a potentially serious but treatable medical condition that occurs when you get too much vitamin D.
Vitamin D toxicity usually results from taking an excessive amount of vitamin D supplements — not from your diet or too much sun exposure. That's because your body regulates the amount of vitamin D produced from sun exposure, and even fortified foods don't contain large amounts of vitamin D.
Although vitamin D toxicity is rare even among people who take supplements, you may be at greater risk if you have health problems, such as liver or kidney conditions, or if you take thiazide-type diuretics. As always, make sure your doctor is aware of any vitamins or supplements you take.
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), causing symptoms such as:
- Vomiting
- Polyuria (frequent urination)
- Weight loss
- Poor appetite
- Constipation
- Weakness
- Heart rhythm abnormalities
- Kidney stones
Treatment of vitamin D toxicity includes stopping vitamin D supplements and restricting calcium intake, as well as taking medication. In severe cases, hospitalization may be necessary.
Supplements can be a reasonable way to meet recommended levels — as long as you pay attention to how much you take. The recommended daily allowance of vitamin D is 600 international units (IU) for children and most adults. The recommendation for adults over age 70 is 800 IU daily. Above 4,000 IU a day the risk of adverse effects increases.
Finally, keep in mind that doctors may recommend higher does of vitamin D for a short time to treat an underlying medical problem such as vitamin D deficiency. However, such doses are given under the care of a doctor.
Next questionToo much vitamin C: Harmful?
- Leu JP, et al. Vitamin D toxicity: Caveat emptor. Endocrine Practice. 2008;14:1188.
- Hemmelgarn M. Shedding light on vitamin D. American Journal of Nursing. 2009;109:19.
- Lee JH, et al. Vitamin D deficiency: An important, common, and easily treatable cardiovascular risk factor? Journal of the American College of Cardiology. 2008;52:1949.
- Dietary Reference Intakes for calcium and vitamin D. Institute of Medicine. http://www.iom.edu/vitamind. Accessed May 25, 2011.
- Hathcock JN, et al. Risk assessment for vitamin D. American Journal of Clinical Nutrition. 2007;85:6.
- Brannon PM, et al. Overview of the conference "Vitamin D and Health in the 21st Century: An Update." American Journal of Clinical Nutrition. 2008;88(suppl):483S.
- Vitamin D. The Merck Manuals: The Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec01/ch004/ch004k.html. Accessed May 25, 2011.
- Hensrud DD (expert opinion). Mayo Clinic, Rochester, Minn. Dec. 9, 2010.
- Dietary Guidelines for Americans, 2010. U.S. Department of Health and Human Services. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm. Accessed May 25, 2011.
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