Novella Lui, RD, MHSc
Key takeaways
- Fluids are important for overall health and are especially crucial during cancer treatment. Staying hydrated may help reduce treatment side effects.
- You can get fluids from both beverages and foods. Fruits and vegetables are especially hydrating.
- Learn more about the side effects of dehydration and the steps you can take to ensure you get enough fluids.
Water intake is crucial to prevent dehydration, especially in hot weather. Water makes up more than 60 percent of your body’s weight, and it’s vital to replenish fluids and stay hydrated every day.
The body loses water through urine and sweat. Drinking beverages and eating foods with high water content can help prevent dehydration, a condition where you lose more fluids than you take in.
Hydration During Cancer Treatment
When you go through cancer treatments such as chemotherapy or radiation, you may be at greater risk of dehydration. That’s because you may lose more fluid from vomiting and diarrhea, or from changes in your appetite that cause you to eat or drink less. Signs of dehydration include:
- Fatigue
- Dizziness
- Headaches
- Constipation
- Dark yellow urine
Staying hydrated may reduce the side effects of cancer treatment. Your healthcare team can recommend ways to deal with side effects and prevent dehydration. For example, if you experience vomiting and diarrhea, your doctor may suggest electrolyte sport beverages to restore fluid levels.
What does fluid do in the body?
- Transports nutrients and waste
- Controls blood pressure
- Maintains body temperature
- Lubricates joints
How Much Water Should I Drink?
There is no singular amount of fluid that everyone requires. And it’s important to note that beside water, many other foods and drinks provide hydration too.
US Guidelines say that an adequate daily fluid intake is 15.5 cups for men and 11.5 cups for women from a combination of all food and drinks (so, not just from water). Typically, about 20 percent of your fluid intake comes from food you eat. The rest comes from beverages, which include water, coffee, tea, soda, juice and anything else.
AICR recommends limiting consumption of sugar-sweetened drinks, such as soda. It’s best to drink mostly water and unsweetened drinks, since there is strong evidence that regularly drinking sugar sweetened drinks is a cause of weight gain, overweight and obesity. Greater body fatness is a cause of at least 12 cancers.
Your exact fluid needs depend on your age, gender, medical conditions, diet, exercise and even the weather. Going through cancer treatment may affect your fluid needs too.
How to Stay Hydrated
Remember to drink: Carry a reusable water bottle and sip all day. Download a hydration app on your phone or set reminders on your phone’s alarm clock to schedule reminders to drink.
Make it tasty: If plain water is bland, try infusing it with cucumber, citrus, berries or herbs, such as basil, rosemary or mint. Or freeze fruit pieces and herbs in ice trays for a more subtle infusion.
Keep track of caffeine: Coffee is 99 percent water and offers hydration but keep the amount to no more than four cups per day. It can be dehydrating above this cutoff level. Tea has one-third to half the caffeine in regular coffee.
Eat foods with high water content: Fluid comes from beverages AND foods. For example, fruits and vegetables are filled with fluid. Or choose fluid-rich low-sodium soups, yogurt, smoothies and applesauce.
- Try these fun fluid-filled ideas:
- Freeze grapes as a snack.
- Make gazpacho or vegetable juice.
- Try chia seed pudding.
- Use popsicle molds to freeze fruit puree into frozen treats.
Foods Help You Stay Hydrated
Many foods contain over 85 percent fluid and help you stay hydrated. Fruits and vegetables are filled with water. Here are some hydrating choices:
| Food | % fluid in food |
| Cucumber | 96% |
| Iceberg lettuce | 96% |
| Celery | 95% |
| Tomatoes | 95% |
| Watermelon | 91% |
| Strawberries | 91% |
| Cantaloupe | 90% |
| Yogurt | 85% |
| Applesauce | 85% |
