- 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 Food & Nutrition Center, 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, she 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 pediatrics at Mayo Clinic Rochester and nutrition education related to the physiology and recommended intakes for premature infants.
Other areas of interest include breast milk and formula safety, neonatal feeding, and nutrition for breast-feeding mothers.
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 (24)
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Healthy diets (9)
- Water after meals: Does it disturb digestion?
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Healthy cooking (8)
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Healthy menus and shopping strategies (7)
- Calories in sushi: What are the low-cal options?
- Vegetable juice: As good as whole vegetables?
- Buying beef? A guide to choosing the leanest cuts
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Nutritional supplements (14)
- Vitamin C: Can too much be harmful?
- Chocolate: Does it impair calcium absorption?
- Percent Daily Value: What does it mean?
- see all in Nutritional supplements
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Question
Vitamin C: Can too much be harmful?
My doctor told me to stop taking vitamin C supplements because too much vitamin C can be harmful. What problems does it cause? Is it possible to take too much vitamin C?
Answer
from Katherine Zeratsky, R.D., L.D.
Vitamin C (ascorbic acid) is a water-soluble vitamin that supports normal growth and development. Vitamin C also helps your body absorb iron. Because your body doesn't produce or store vitamin C, it's important to include vitamin C in your diet. For most people, a small glass of orange juice and a cup of strawberries, a medium orange, or a serving of broccoli provide enough vitamin C for the day. Any extra vitamin C will simply be flushed out of your body in your urine. Still, it's possible to have too much of a good thing. Although too much vitamin C from your diet is unlikely to harm you, megadoses of vitamin C supplements can cause nausea, diarrhea, kidney stones and inflammation of the stomach lining (gastritis). Rarely, too much vitamin C can cause faintness, dizziness and fatigue.
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