Will drinking more water cure constipation?

How effective is water therapy for constipation?

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Constipation is a condition that is characterized by a slow intestinal transit and an output of small and hard stools with infrequent and difficult passage. It can occur in any age group.

It afflicts millions of people around the world (perhaps 20% of the world's population suffers from constipation).

The most common reccomendation given to constipated patients is to increase fluid intake to improve bowel movements.

In this article we will review the scientific facts behind constipation and check the truth behind the condition and also learn if water can help treat it.

Constipation: its causes

Hydration may help treat constipation

There are several possible causes for constipation:

  • A diet low in fiber (lacking fruit, vegetables, grain).
  • Not drinking enough fluids.
  • Sedentary lifestyle (lack of exercise).
  • Changes in diet or daily routine.
  • Side effect of a medication.
  • Mood changes: depression, stress, anxiety.
  • Not listening to your body: ignoring the urge to go to the toilet.
  • Medical conditions (these can be quite serious).

Among the medical conditions are the following: bowel obstruction, abdominal cancer, neurological problems (multiple sclerosis, Parkinson's disease, stroke), diabetes, hormonal problems (thyroid or parathyroid glands).

Introduction: The Digestive System

Food is digested in a semi-continuous process that begins when it is chewed and mixed with saliva in the mouth. After being swallowed it reaches the stomach through a tube called the esophagus. It is broken down by some enzimes and hydrochloric acid in the stomach and released into the small intestine with additional gastric juices from the gall bladder and pancreas.

The walls of the small intestine absorb the nutrients contained by the now broken-down food and send them into the blood for processing, use and storage.

The small intestine can absorb up to 4 gallons per day (15 liters) of fluids.

What remains moves into the large intestine where trillions of microbes contribute to the final stages of digestion. Most of the water that remains in what is now "waste" is absorbed.

The final segment of the large intestine, the colon, absorbs the remaining water (up to 1.3 gallons per day - 5 liters), returning these fluids to the body.

The final waste which is a mix of undigested fiber and millions of bacteria is stored in the rectum and finally expelled from the body as stool on a regular basis.

Water and constipation

The reasoning behind suggesting that a higher water intake can cure constipation is that it will balance the fluids extracted by the large intestine and keep stool humid and soft, facilitating its passing.

The bad news is that several studies have shown that hydration alone can't cure constipation in individuals who are normally hydrated. Let's look into these stucies:

It is not effective

Sun (2014) ( 1 ) finds no evidence to support water intake as a treatment for constipation: "Against common sense that drinking water is helpful for constipation, many well-known studies [...] insist that no evidence supports the use of extra fluid intake to treat functional constipation".

Tabbers (2014) ( 2 ) echoes that same opinon: they didn't find that a higher water intake was an effective treatment for constipated children.

Drinking Water will not cure constipation unless you are dehydrated

Young (1998) ( 3 )found that small children suffering from chronic constipation did not improve even after increasing their daily water intake by 50%. This finding was confirmed by Arnaud (2003) ( 4 ) who also found that water therapy was not effective as a treatment for constipation.

Chung (1999) ( 5 ) recruited 15 healthy young subjects with no history of constipation and increased their baseline fluid intake with either water or an isotonic drink (i.e. Gatorade).

Despite an increased intake of fluids (of one and two quarts - 1 and 2 liters) the study didn't find any change in stool output (urine output on the other hand did increse significantly).

The authors concluded that "Despite common medical advice to consume extra fluid for constipation, our results indicate that extra fluid intake in normal healthy volunteers did not produce a significant increase in stool output."

Extra water in pregnant women may prevent constipation

A study by Fitriana (2018) ( 6 ) involving pregnant Indonesian women found "a significant association between fluid intake and constipation" and concluded that "Inadequate maternal fluid intake can increase the risk of constipation by 1.85 folds, and the adequate fluid intake may prevent constipation during pregnancy. "

Old people can benefit from extra water intake

Nevertheless, in older individuals, low fluid intake is a predictor for increased levels of acute constipation (Lindeman, 2000) ( 7 ), (Robson, 2000) ( 8 ): Those consuming the least amount of fluid had over twice the frequency of constipation episodes than those consuming the most fluid.

Arnaud (2003) (4) noted that low fluid intake in elderly subjects, a sure sign of hypohydration (not hydrated enough) "was a cause of constipation". And that those who drank 500 to 2500 ml less fluids than required had a significant relationship between their liquid deprivation and constipation, so in that group "It is thus important to maintain [normal levels of hydration] as a prevention of constipation".

Water therapy is not effective in all older people

Tsindos (2015) ( 10 ) studied a group of senior citizens aged 65 and over and found that they ingested an average of 2.87 liters of water daily of which 36.5% was provided by their food "those who self-reported no constipation consumed nearly 300ml more water in foods than those who self-reported being constipated.". This is roughly 1 1⁄2 extra glasses of water but, water that is in the food, not as an extra liquid intake.

Tsindos concludes: "Water consumption from food was significantly higher in those with no constipation suggesting that consumption of water in food may be a significant factor in ensuring adequate water needs".

The link with food is another option when treating constipation: increase fiber intake is suggested as another cure for this condition.

Fiber and Constipation

Perhaps Tsindos (10) whom we mentioned further up, has identified something beyond mere hydration by pinpointing the "consumption of water in food" as a factor that improves constipation: it is likely that the combination of fibre and bulk provided by food contibutes to the hydrating effect in the body.

Low Fiber is one of the culprits

Murakami (2007) ( 11 ) studied Japanese women who ate a diet with very low fiber content and found that this low fiber intake coupled to a low water intake was associated with "increased prevalence of constipation".

However Fitriana (2018) (6) mentioned further up (pregnant Indonesian women) did not find any "significant association between fiber intake and constipation"

man holding belly, in pain
Constipation affects 20% of the world's population

Anti (1998) ( 12 ) studied 117 patients suffering from chronic functional constipation. They divided them into two groups and gave both groups a standard diet that included 25 g of fiber per day. Water intake was monitored: Group 1 consumed 1.1 liters per day while Group 2 had a daily intake that averaged 2 litres. The outcome was:

  • Both groups showed a "statistically significant increases in stool frequency and decreases in laxative use during the two-month trial."
  • Group 2 (which drank more water) showed greater changes compared against Grup 1 and laxative use.

Anti concluded that "A daily fiber intake of 25 g can increase stool frequency in patients with chronic functional constipation, and this effect can be significantly enhanced by increasing fluid intake to 1.5-2.0 liters/day."

Fathallah (2017) ( 13 ) supports fiber supplementation with a 20 to 25 g daily intake. Considering it "the most relevant measure [because] it improves stool frequency and consistency. It has a positive effect on excessive straining and colonic transit time".

Fiber may cause abdominal pain, flatulence and bloating (fibers ferment in the gut) so it should be incorporated gradually into the diet over a period of several days.

Fathallah considers additional water intake or exercising as options in special situations such as institutionalized, dehydrated, elderly or hospitalized patients. For regular subjects those treatments are "probably anecdotal recommendations".

Borre (2017) ( 14 ) agrees, considering that fiber, fluid and exercise are reccomendations based on scarce evidence. Nevertheless they concede that "Increased intake of fibre will reduce colonic transit time and improve the frequency and consistency of stools in 50% of patients."

Tabbers (2011) ( 15 ) in an analysis of 9 studies covering childhood constipation (640 children) concluded that: "There is some evidence that fiber supplements are more effective than placebo. No evidence for any effect was found for fluid supplements, prebiotics, probiotics, or behavioral intervention."

Yet Jing (2012) ( 9 ), who performed a meta-analysis (a statistical procedure for combining data from multiple studies) and concluded that "Detary fiber intake can obviously increase stool frequency in patients with constipation. It does not obviously improve stool consistency, treatment success, laxative use and painful defecation."

Closing comments

Apparently a diet that includes adequate fiber intake (25 g daily) is a proven method for treating constipation. It can be supplemented with additional water intake, ideally to reach the daily intake value of recommended by the National Academy of Medicine (NAM) for adults over the age of 19:

  • 91 ounces of total water for women (2.7 liters)
  • 125 ounces of total water for men (3.7 liters)

Read More at our:

> > Do I need 8 Glasses of Water a Day? webpage
(the myth of the "8 x 8" rule)

Excercise, prebiotics and probiotics are said to help but scientific studies haven't provided evidence of their effectiveness.

Cite this article:

. ©2018. Water intake and Constipation. Patagonia Wellness, 11 Oct. 2018. http://www.patagoniawellness.com/health/water-and-constipation.html

Tags: constipation, dehydration, 8 x 8 rule, hydration, water requirements, daily water intake

Subject: Constipation and Water intake. Does extra hydration and water intake cure constipation?


References and Further Reading

(1) Sun Hwan Bae (2014). Diets for Constipation, Pediatr Gastroenterol Hepatol Nutr. 2014 Dec; 17(4): 203-208. Published online 2014 Dec 31. doi: 10.5223/pghn.2014.17.4.203

(3)Young RJ, Beerman LE, Vanderhoof JA, (1998). Increasing oral fluids in chronic constipation in children, Gastroenterol Nurs. 1998;21:156-161

(4) Arnaud MJ (2003). Mild dehydration: a risk factor of constipation?, Eur J Clin Nutr. 2003 Dec;57 Suppl 2:S88-95. DOI: 10.1038/sj.ejcn.1601907

(5) Chung BD, Parekh U, Sellin JH, (1999). Effect of increased fluid intake on stool output in normal healthy volunteers, J Clin Gastroenterol. 1999 Jan;28(1):29-32

(6) Fitriana, Dina & Prasetyo, Budi & Trapsila Purwaka, Bangun. (2018). Inadequate fluid intake can increase the risk of constipation among pregnant women, Majalah Obstetri & Ginekologi. 25. 48. 10.20473/mog.V25I22017.48-53

(7) Lindeman RD et al. (2000). Do elderly persons need to be encouraged to drink more fluids?, J Gerontol A Biol Sci Med Sci. 2000;55:M361-365

(8) Robson KM, Kiely DK, Lembo T, (2000). Development of constipation in nursing home residents, Dis Colon Rectum. 2000;43:940-943

(9) Jing Yang, Hai-Peng Wang, Li Zhou, and Chun-Fang Xu, (2012). Effect of dietary fiber on constipation: A meta analysis, World J Gastroenterol. 2012 Dec 28; 18(48): 7378-7383. doi: 10.3748/wjg.v18.i48.7378

(10) Tsindos, P. S., Itsiopoulos, C. and Kouris-Blazos, A., (2015). Investigation into water consumption and its influence on depression, memory problems and constipation in older persons, Journal of aging research & clinical practice, vol. 4:3 137-143, doi: 10.14283/jarcp.2015.65

(11) Murakami K, Sasaki S, Okubo H, et al. (2007). Association between dietary fiber, water and magnesium intake and functional constipation among young Japanese women, Eur J Clin Nutr. 2007;61:616-622

(13) Fathallah N, Bouchard D, de Parades V., (2017) Diet and lifestyle rules in chronic constipation in adults: From fantasy to reality..., Presse Med. 2017 Jan;46(1):23-30. doi: 10.1016/j.lpm.2016.03.019. Epub 2017 Jan 5

(14) Borre M. et al., (2015). The effect of lifestyle modification on chronic constipation, Ugeskr Laeger. 2015 Apr 6;177(15):V09140498

(15) Tabbers MM, Boluyt N, Berger MY, Benninga MA., (2011). Nonpharmacologic treatments for childhood constipation: systematic review, Pediatrics. 2011 Oct;128(4):753-61. doi: 10.1542/peds.2011-0179. Epub 2011 Sep 26