- With Mayo Clinic nutritionist
Katherine Zeratsky, R.D., L.D.read biographyclose window
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.
Nutrition basics (31)
- Phenylalanine in diet soda: Is it harmful?
- Diet soda: Is it bad for you?
- Stevia: Can it help with weight control?
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Healthy diets (10)
- Canola oil: Does it contain toxins?
- Butter vs. margarine: Which is better for my heart?
- Detox diets: Do they work?
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Healthy cooking (7)
- When the heat is on, which oil should you use?
- Moldy cheese: Is it OK to eat?
- Food poisoning: How long can you safely keep leftovers?
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Healthy menus and shopping strategies (8)
- Calories in sushi: What are the low-cal options?
- White whole-wheat bread: Is it nutritious?
- Sodium nitrate in meat: Heart disease risk factor?
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Nutritional supplements (18)
- What is wheatgrass — And why is it in my drink?
- Do the benefits of vitamin C include improved mood?
- Prenatal vitamins: OK for women who aren't pregnant?
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Vitamin D toxicity: What if you get too much?
What is vitamin D toxicity, and should I worry about it since I take supplements?
from Katherine Zeratsky, R.D., L.D.
Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body.
Vitamin D toxicity is usually caused by megadoses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D.
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause symptoms such as poor appetite, nausea and vomiting. Weakness, frequent urination and kidney problems also may occur. Treatment includes the stopping of excessive vitamin D intake. Your doctor may also prescribe intravenous fluids and medications, such as corticosteroids or bisphosphonates.
Taking 50,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the recommended dietary allowance (RDA) for most adults of 600 IU of vitamin D a day. Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor and only for a short time.
Although vitamin D toxicity is uncommon 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, talk to your doctor before taking vitamin and mineral supplements.Next question
Too much vitamin C: Harmful?
- Vitamin D. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec01/ch004/ch004k.html. Accessed Dec. 23, 2011.
- Dietary Reference Intakes for calcium and vitamin D. Institute of Medicine. http://www.iom.edu/vitamind. Accessed Dec. 23, 2011.
- Dietary Guidelines for Americans, 2010. U.S. Department of Health and Human Services. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm. Accessed Dec. 23, 2011.
- Hathcock JN, et al. Risk assessment for vitamin D. American Journal of Clinical Nutrition. 2007;85:6.
- 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.
- Lowe H, et al. Vitamin D toxicity due to a commonly available 'over the counter' remedy from the Dominican Republic. Journal of Clinical Endocrinology and Metabolism. 2011;96:291.