The large intestine, or colon, is part of the digestive system. While it has several roles, individuals can live without it. Surgical removal, called a colectomy, is performed for various medical conditions.
The Large Intestine’s Essential Role
After the small intestine absorbs most nutrients, the large intestine processes indigestible food, absorbs water, and maintains electrolyte balance. While the small intestine absorbs most water, the large intestine absorbs remaining water and solidifies waste into stool. This process prevents dehydration and forms feces for elimination.
The large intestine also houses gut microbiota. These bacteria ferment undigested carbohydrates, like dietary fiber, into short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate. SCFAs provide energy for colon cells and support gut health. Colonic bacteria also produce vitamins, like K and some B vitamins, which the body can absorb.
Medical Reasons for Removal
Colectomy becomes necessary for various medical conditions. Inflammatory bowel diseases like ulcerative colitis and Crohn’s disease may require this when medication fails or complications arise. Ulcerative colitis, for example, can cause chronic inflammation and ulcers, sometimes requiring removal to alleviate symptoms or reduce cancer risk.
Colorectal cancer is another reason for colectomy, where diseased sections are removed to prevent spread. Other conditions include complicated diverticular disease, where pouches become inflamed or infected. Intestinal blockages, uncontrolled gastrointestinal bleeding, precancerous polyps, and large bowel injuries may also require surgery.
Adapting to Life Without a Large Intestine
Life without a large intestine involves adjustments to digestive function and daily habits. The main change is often increased frequency and looser bowel movements due to reduced water absorption. Individuals may experience 4 to 6 liquid bowel movements daily. This altered function also increases dehydration risk, making consistent fluid intake important.
Dietary modifications are necessary to manage these changes. Initially, a low-fiber diet is recommended to reduce strain on healing intestines and minimize gas or blockages. Over time, individuals reintroduce foods, focusing on smaller, frequent meals to aid digestion. Avoiding foods that worsen diarrhea or gas, such as raw vegetables, high-fiber cereals, or acidic fruits, can improve comfort.
Surgical Procedures and Their Implications
When the large intestine is removed, surgeons use different techniques to manage waste elimination, each with implications for a patient’s life. One outcome is an ostomy, creating a stoma (an opening on the abdominal wall) to divert waste. An ileostomy brings the small intestine’s end (ileum) through the abdominal wall, collecting waste in an external pouch. A colostomy brings part of the large intestine to the abdominal wall, also requiring an external pouch. These ostomies can be temporary, allowing the bowel to heal, or permanent, depending on disease extent and possibility of rejoining intestines.
An alternative for some patients is an internal pouch, called a J-pouch or ileoanal anastomosis. This procedure constructs a new reservoir from the small intestine, connected directly to the anus, allowing natural waste elimination without an external bag. This complex surgery is often performed in stages, with a temporary ileostomy created initially to allow the pouch to heal. While the J-pouch allows internal waste storage, bowel movements will still be more frequent and looser than with an intact large intestine. Recovery involves a hospital stay of several days, with full recovery taking weeks to months as patients resume normal activities and adjust to new bowel patterns.