- 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?
- see all in Nutrition basics
Healthy diets (10)
- Canola oil: Does it contain toxins?
- Butter vs. margarine: Which is better for my heart?
- Detox diets: Do they work?
- see all in Healthy diets
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?
- see all in Healthy cooking
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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Too much vitamin C: Harmful?
Is it possible to take too much vitamin C?
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:
- Abdominal bloating and cramps
- Kidney stones
Remember, for most people, a healthy diet provides an adequate amount of vitamin C.Next question
Percent Daily Value: What does it mean?
- 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.