- With Mayo Clinic nutritionist
Katherine Zeratsky, R.D., L.D.
read biographyclose windowBiography of
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)
- Water softeners: How much sodium do they add?
- Fat grams: How to track your dietary fat
- Yerba mate: Is it safe to drink?
- 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?
- What is BPA? Should I be worried about it?
- Brominated vegetable oil: Why is BVO in my drink?
- see all in Healthy menus and shopping strategies
Nutritional supplements (18)
- Ground flaxseed: Better than whole?
- Fiber supplements: Safe to take every day?
- Chocolate: Does it impair calcium absorption?
- see all in Nutritional supplements
Free
E-newsletter
Subscribe to Housecall
Our weekly general interest
e-newsletter keeps you up to date
on a wide variety of health topics.
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Question
Caffeine: Is it dehydrating or not?
I've been seeing ads that say caffeinated drinks hydrate you as well as water does. Is this true?
Answer
from Katherine Zeratsky, R.D., L.D.
It is true that caffeinated fluids can contribute to your daily fluid requirement.
Drinking caffeine-containing beverages as part of a normal lifestyle doesn't cause fluid loss in excess of the volume ingested. While caffeinated drinks may have a mild diuretic effect — meaning that they may cause the need to urinate — they don't appear to increase the risk of dehydration.
Still, caffeinated drinks can cause headaches and insomnia in some people. Water is probably your best bet to stay hydrated. It's calorie-free, caffeine-free, inexpensive and readily available.
Next questionGrape juice: Same heart benefits as wine?
- Armstrong LE, et al. Caffeine, fluid-electrolyte balance, temperature regulation, and exercise-heat tolerance. Exercise and Sport Sciences Review. 2007;35:135.
- Maughan RJ, et al. Caffeine ingestion and fluid balance: A review. Journal of Human Nutrition and Dietetics. 2003;16:411.
- Lopez RM, et al. The influence of nutritional ergogenic aids on exercise heat tolerance and hydration status. Current Sports Medicine Reports. 2009;8:192.
- Ruxton CH, et al. Black tea is not significantly different from water in the maintenance of normal hydration in human subjects: Results from a randomized controlled trial. British Journal of Nutrition. 2011;106:588.
- Heneghan C, et al. Mythbusting sports and exercise products. BMJ. 2012;345:e4848.
- Caffeine. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Aug. 13, 2013.
- Zeratsky KA (expert opinion). Mayo Clinic, Rochester, Minn. Aug. 13, 2013.
Find Mayo Clinic on