Why is water important?

Water makes up over 60% of our body weight and is involved in every biochemical reaction in our bodies, making it essential for human life.

Water is critical for digestion and absorption of food and minerals. The intestinal juices that break down your food and allow your body to absorb the nutrients into the bloodstream is primarily composed of the water we drink.

Our blood is mostly water, and allows us to move oxygen and glucose to our muscles.

Water also helps us regulate our body temperature through sweat, eliminate toxins from our body through urination, lubricate the joints between our bones as the main component of synovial fluid, and help prevent blockages from happening with an ostomy.

What Are the Common Signs of Dehydration?

  • Headache
  • Dizziness
  • Fatigue
  • Feeling thirsty or having dry mouth
  • Nausea or abdominal cramping
  • Dark colored urine
  • Dry and/or flushed skin
  • Constipation and/or blockages
  • Muscle cramps
  • Increased heart rate

What Are Some Causes of Dehydration?

  • Vomiting / Diarrhea / High Output
  • Inadequate fluid and electrolyte intake
  • Sweating without fluid replacement
  • Diuretic drugs or food
  • Gastrointestinal fluid losses

Knowing Your Body:
Where and How Hydration Occurs

Where Water Absorption Happens: Your Intestinal Tract

Water absorption happens primarily in the small intestine, which is made up of 3 parts: duodenum, jejunum, and ileum.

It is estimated that 80% of the fluids we ingest are absorbed in the proximal small intestine, or the duodenum, which is the first part of your small intestine.

The remaining 20% of water absorption comes from the food we eat, which happens primarily in the large intestine.

For those ostomy patients who have their colon or large intestine removed, they no longer have that 20% absorption of water. This can oftentimes result in dehydration.


How Water Absorption Happens: Electrolytes

In order for you to absorb water from your intestines into the rest of your body, it is important to maintain a good balance of electrolytes and minerals.

Electrolytes are tiny particles that carry electrical charges necessary for pulling water from the gut into the bloodstream and the rest of the body.

There are 8 primary electrolytes your body needs to absorb water properly. These include:

  • The positively charged electrolytes are: sodium, potassium, magnesium, and calcium.
  • The negative electrolytes are: chloride, bicarbonate, phosphate, and sulfate.
  • Sites of water and mineral absorption

Tips for Staying Hydrated With an Ostomy

Depending on what type of ostomy you have, your body's ability to absorb water and nutrients effectively may vary.

Consider how much of your large intestine is intact still (colostomy), or if you have no colon (Ileostomy). Between 20-30% of your body's absorption of water comes from the food you eat when it passes through the large intestine. With this in mind you can calculate how much additional water and electrolytes your body may need to become properly hydrated. It should also be noted that some of the absorption of sodium, potassium, and vitamin K is done in the large intestine, so it may be necessary to add those electrolyte supplements to your fluids to compensate for a missing colon.


Avoid High-Output Triggers

Certain foods and drinks can have a diuretic effect, and can cause you to lose fluids before they are able to be absorbed.

If you struggle with dehydration and often have high volumes of liquid output, consider eliminating some of these from your diet:

  • sweets
  • artificial sweeteners
  • lactose rich foods and drink
  • alcohol
  • caffeine
  • carbonated drinks
  • legumes, beans, or lentils
  • high-fiber vegetables
  • nuts and seeds
  • whole wheat or corn products such as bran or popcorn

Sip water frequently throughout the day. The average amount of water you should drink includes: 2.2 liters for women and 3 liters for men, although these numbers may vary based on a number of factors including activity level, weight, temperature and humidity, and diet.

Suggestions for Drinks and Electrolyte Supplements

You should always consult your physician before starting a new electrolyte supplement routine. It may be worthwhile to have bloodwork done to identify which specific areas your hydration is lacking. Not everyone will need to supplement with extra electrolytes to achieve hydration.


For those who do need supplementation, here are a list of some different options to consider:

  • Oral Rehydration Solutions:Ask your doctor if an Oral Rehydration Solution (ORS) is right for you. Some ORS supplements include: H2ORS, SOS, DripDrop, Liquid I.V. (and more)
  • Low Calorie Electrolyte Replacement: Other possible electrolyte replacement options include: GU Energy Tabs, NUUN, Pedialyte,
  • High Carbohydrate Electrolytes:Some electrolyte or sports drinks are high in sugar (carbohydrates). These drinks should be reserved for mid-exercise, as they are specifically formulated for endurance athletics. Drinking high sugar fluids outside of intense exercise can have a diuretic effect, causing dehydration to become more likely, as well as added weight gain from increased calorie consumption. Some examples of these sports drinks include: Gatorade, Powerade, Vitamin Water, etc.
  • Other Options:Not all of your fluids need to have added electrolytes in them. Oftentimes, people simply don't drink enough plain water. Here are a few good options to go along with water that work well for rehydration: low sugar coconut water, watered down juice, tea, lactose-free milk, almond or oat milk.


  • IOM (Institute of Medicine of the National Academies) (2004) Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. 4: 73-185. National Academies Press, Washington, DC.
  • EFSA Panel on Dietetic Products Nutrition and Allergies (NDA). (2010) Scientific Opinion on Dietary Reference Values for water. EFSA Journal. 8(3): 1459-1507.
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  • Pivarnik JM and Palmer RA. (1994) Water and electrolytes during exercise. In: Hickson, J. F and Wolinski, I., ed. Water and electrolyte balance during rest and exercise. Boca Raton; CRC Press, 245-262.
  • Tanner GA. (2009) The Regulation of Fluid and Electrolyte Balance. In: Rhoades, R. A. and Bell, D. R., ed. Medical Physiology Principles for Clinical Medicine. 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 419-441.