- 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.
Caffeine: Is it dehydrating or not?
I’ve been seeing ads that say cola and coffee drinks hydrate you as well as water does. Is this true?
from Katherine Zeratsky, R.D., L.D.
It is true. Researchers used to believe that caffeinated drinks had a diuretic effect. This means that you would urinate more after drinking them, which could increase your risk of becoming dehydrated. Recent research shows that this is not true and that caffeine has a diuretic effect only if you consume large amounts of it — more than 500 to 600 milligrams (the equivalent of 5 to 7 cups of coffee) a day.
Still, caffeinated drinks at these levels can make you jittery, sleepless or anxious. Water is probably your best bet to stay hydrated. It’s calorie-free, caffeine-free, inexpensive and readily available.
Underweight? See how to add pounds healthfully
- Water: How much should you drink every day?
- Pyramid or plate? Explore these healthy diet options
- Added sugar: Don’t get sabotaged by sweeteners
- Sodium: How to tame your salt habit now
- Artificial sweeteners: Understanding these and other sugar substitutes
- Carbohydrates: How carbs fit into a healthy diet
- New dietary guidelines: How to make smart choices
- Dietary fats: Know which types to choose
- Alcohol use: If you drink, keep it moderate
- Caffeine: How much is too much?
- Dietary fiber: Essential for a healthy diet
- Nutrition Facts: An interactive guide to food labels
- Healthy chocolate: Dream or reality?
- Multigrain vs. whole grain: Which is healthier?
- Underweight? See how to add pounds healthfully
- Grape juice: Same heart benefits as wine?
- Slide show: Healthy meals start with smart meal planning
- Water softeners: How much sodium do they add?
- Olive oil: What are the health benefits?
- Fat grams: How to track your dietary fat
- Stevia: Can it help with weight control?
- Phenylalanine in diet soda: Is it harmful?
- Low-sodium diet: Why is processed food so salty?
- Healthy diet: End the guesswork with these nutrition guidelines
- MUFAs: Why should my diet include these fats?
- High-fructose corn syrup: What are the health concerns?
- Juicing: What are the health benefits?
- Taurine in energy drinks: What is it?
- What are functional foods?
- High-protein diets: Are they safe?
- Acai berry products: Do they have health benefits?
- Slide show: Guide to a high-fiber diet
- Coffee and health: What does the research say?
- Alkaline water: Better than plain water?
- Calorie calculator
- Slide show: 10 great health foods for eating well
- Energy drinks: Do they really boost energy?
- High-fiber foods
- Diet soda: Is it bad for you?
- Monosodium glutamate (MSG): Is it harmful?
- Yerba mate: Is it safe to drink?
- Slide show: Guide to portion control for weight loss
- Can whole-grain foods lower blood pressure?
- Junk food blues: Are depression and diet related?
- Trans fat is double trouble for your heart health
- Nuts and your heart: Eating nuts for heart health
- Cholesterol: Top 5 foods to lower your numbers
- Healthy heart for life: Avoiding heart disease
- Omega-6 fatty acids: Can they cause heart disease?
- Foods for healthy skin: Top picks
- Tips for healthy eating
- Mayo Clinic Healthy Weight Pyramid tool
- Step up to MyPlate, the new food icon
- Section Focus
- Related Links
- 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. In press. Accessed June 2, 2011.
- Zeratsky KA (expert opinion). Mayo Clinic, Rochester, Minn. June 2, 2011.