- 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.
Nutrition basics (30)
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Healthy diets (10)
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- Water after meals: Does it disturb digestion?
- Diverticulitis diet: Can certain foods trigger an attack?
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Healthy cooking (6)
- E. coli: How can I tell if food is contaminated?
- Canned pumpkin: Better than fresh?
- Food poisoning: How long can you safely keep leftovers?
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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?
- Sodium nitrate in meat: Heart disease risk factor?
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Nutritional supplements (16)
- Ground flaxseed: Better than whole?
- Chocolate: Does it impair calcium absorption?
- What is wheatgrass — And why is it in my drink?
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Question
Too much vitamin C: Harmful?
Is it possible to take too much vitamin C?
Answer
from Katherine Zeratsky, R.D., L.D.
Vitamin C (ascorbic acid) is an essential nutrient. Still, it's possible to have too much vitamin C.
Vitamin C 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 large orange, 1 cup (about 165 grams) of sliced strawberries, chopped red pepper or broccoli provide enough vitamin C for the day. Any extra vitamin C will simply be flushed out of your body in your urine.
For adults, the recommended dietary reference intake for vitamin C is 65 to 90 milligrams (mg) a day, and the upper limit is 2,000 mg a day. Although too much dietary vitamin C is unlikely to be harmful, megadoses of vitamin C supplements may cause:
- Diarrhea
- Nausea
- Vomiting
- Heartburn
- Abdominal bloating and cramps
- Headache
- Insomnia
- Kidney stones
Remember, for most people, a healthy diet provides an adequate amount of vitamin C.
Next questionVitamin water: Better than plain water?
- Vitamin C (ascorbic acid). Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Jan. 9, 2012.
- Dietary Guidelines for Americans, 2010. U.S. Department of Health and Human Services. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm. Accessed Jan. 9, 2012.
- Pazirandeh S, et al. Overview of water-soluble vitamins. http://www.uptodate.com/home/index.html. Accessed Jan. 9, 2012.
- Vitamin C. Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional. Accessed Jan. 9, 2012.
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