La diarrhée chez l’adulte


Diarrhea is not a digestive illness per se, but rather a symptom of an underlying illness. It usually consists of sudden and frequent passing of watery stools. Diarrhea can lead to a significant loss of fluids and electrolytes eg. : sodium, magnesium, chlorine, potassium, sometimes associated with dehydration. It may be accompanied by abdominal and perianal pain, gas, cramps, incontinence, weakness, nausea, vomiting, and fever.fièvre.


Diarrhea can be acute or chronic, depending on how long it lasts. Acute diarrhea lasts less than a week and its most common causes include viral, parasitic or bacterial infections eg. : gastroenteritis and food poisoning. Chronic diarrhea lasts more than four weeks and its most common causes include irritable bowel syndrome and Crohn's disease.n.  


There are four classes of diarrhea, depending on their cause:

Osmotic diarrhea

Osmotic diarrhea results from the consumption of substances with little or no absorption. When these substances are present in excess in the intestine, they retain water, which leads to the evacuation of watery stools. Some causes of osmotic diarrhea include malabsorption of ex carbohydrates. : lactose intolerance, excessive consumption of poorly absorbable carbohydrates eg. : fructose, magnesium ex. : laxatives, antacids and laxatives containing poorly absorbable elements eg. : phosphate. Finally, osmotic diarrhea ceases with fasting or avoidance of the offending substance (s).criminées.  

Secretory diarrhea

Secretory diarrhea is characterized by the excessive secretion of water and electrolytes from the intestine. The causes of secretory diarrhea include bacterial agents ex. :. : E. coli), bile acid malabsorption ex. : in case of intestinal resection, malabsorption of long chain fatty acids eg. : steatorrhea, certain laxatives eg. : castor oil, a hormonal disorder and chronic alcohol ingestion. This class of diarrhea continues despite fasting.e jeûne.

Exudative / inflammatory diarrhea

Leaky or inflammatory diarrhea is secondary to various factors that can affect the intestinal lining, such as Crohn's disease, viral infections, parasites, or radiation therapy. The secretion of plasma, serum proteins, mucus, and blood from the intestine increases the bulk and liquid content of the stool, causing diarrhea..

Diarrhea due to accelerated transit

Diarrhea caused by accelerated transit results from the reduction in contact time between digesting food and the absorption surface of the intestine. Decreasing the contact time reduces the amount of fluids absorbed by the intestine, leading to diarrhea. Accelerated gastric emptying can be caused by various factors, such as irritable bowel syndrome, resection of part of the intestine, and certain medications.aments.

Nutritional approach

The nutritional treatment of diarrhea in adults aims to correct water loss and restore electrolyte balance, find and eliminate, if possible, the cause of diarrhea, prevent recurrence and prevent and correct nutritional disorders. and weight loss in chronic diarrhea. In general, the correction of hydration and the re-establishment of electrolyte balance is done using a rehydration solution, including the composition of water, carbohydrates, electrolytes and the route of administration ex. : oral or intravenous depend on the hydration status of the individual eg. : slightly versus severely dehydrated. Then, the dietary recommendations depend on the type of acute or chronic diarrhea, its classification eg. : osmotic, secretory, inflammatory and the underlying disease at its origin ex. : Crohn's disease, irritable bowel syndrome, celiac disease, etc. For example, for acute diarrhea occurring as part of gastroenteritis, dietary recommendations may include:ntaires peuvent inclure :

  • Start with a fiber-restricted diet and gradually progress to a normal diet
  • Eat several small meals a day
  • Pay attention to lactose consumption secondary lactase deficiency is possiblee)
  • Observe a diet without excess of concentrated sugars eg. : polyols, fructose, sucrosee)
  • Consume probiotics, especially if gastroenteritis is caused by bacteria, such as difficult, or following antibiotic treatment.

Finally, it is possible that the frequency of bowel movements continues to increase during treatment and it may take a few days for the stool to return to normal appearance. For chronic diarrhea, dietary recommendations are more extensive depending on the underlying disease eg. : irritable bowel syndrome or celiac disease. Finally, in order to obtain recommendations adapted to your specific needs, do not hesitate to consult a health professional who will know how to individualize his treatment to your particular case.ulier.



- Bouthillier, Lise. January 2019. Diseases of the digestive tract. NUT 2047 Clinical nutrition 2. Montreal: University of



Article written by:

Marie-Noël Marsan, Nutritionist