Enteral nutrition (liquid feeds) for maintenance of remission in Crohn's disease

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What is Crohn’s disease?

Crohn’s disease is a chronic inflammatory disease of the intestines that frequently occurs in the lower part of the small intestine (ileum). Symptoms include abdominal pain, diarrhoea and weight loss. When people with Crohn’s disease are experiencing symptoms the disease is considered ‘active’. When the symptoms stop, it is called ‘remission’. When people in remission experience symptoms it is called a ‘relapse‘.

What is enteral nutrition?

Enteral nutrition is a feeding method where a person’s daily caloric intake is delivered via a liquid diet using the GI tract. Enteral nutrition can be administered by mouth or by tube feeding, where a tube is inserted through the nose or abdomen into the stomach to deliver the liquid feed. Enteral nutrition is a form of nutritional therapy for Crohn’s disease patients. The mechanism by which enteral nutrition may influence inflammation is unknown and is being studied. Enteral nutrition can be classified as elemental and non-elemental (semi-elemental and polymeric) diets. Elemental diets are composed of amino-acids (organic compounds), fats, sugars, vitamins and minerals. Elemental diets are easily absorbed and digested. Non-elemental diets are based on oligopeptide (organic compounds composed of 2 to 20 amino-acids) or whole protein sources. Non-elemental diets are best for people who can digest and absorb nutrients without difficulty.

What is 6-mercaptopurine?

6-Mercaptopurine is an immunosuppressive drug that is thought to reduce inflammation in people with Crohn’s disease by blocking the immune system.

What is mesalamine?

Mesalamine is a 5-aminosalicylic acid drug. 5-Aminosalicylic drugs are thought to treat Crohn’s disease by reducing inflammation in the gastrointestinal tract. These drugs are usually taken by mouth.

What did the researchers investigate?

The researchers studied whether enteral nutrition helps to maintain remission in people with Crohn’s disease. The researchers also investigated whether one type of enteral nutrition was better than another (e.g. elemental vs.non-elemental) for maintaining remission in people with Crohn’s disease.

What did the researchers find?

Four studies including 262 adult participants with Crohn’s disease in remission were included. One study (33 participants) compared an elemental diet to a non-elemental (polymeric) diet. One study (51 participants) compared an elemental diet to a normal diet (no supplements). One study (95 participants) compared an elemental diet to 6-mercaptopurine or a no treatment control group. One study (83 participants) compared a non-elemental polymeric diet to mesalamine. The researchers searched the medical literature extensively up to 27 July 2018.

The study comparing an elemental diet to a polymeric diet found no difference in remission rates at 12 months. Six elemental diet participants were not able to tolerate the enteral nutritional formula because of taste or smell and were withdrawn from the study. Participants who received half of their total daily calorie requirements as elemental diet and the remaining half by normal diet had a lower chance of relapse at 12 months compared to participants who received a free diet. No side effects were reported in this study. The study comparing an elemental diet to 6-mercaptopurine did not show any difference in relapse rates at 12 months. There was no difference in side effect rates. The only side effect reported in the elemental diet group was surgery due to worsening Crohn’s disease. Side effects in the 6-mercaptopurine group included liver injury in two participants, hair loss in one participant and surgery to treat an abscess in one participant. The study comparing a polymeric diet to mesalamine found no difference in relapse rates at six months. Two participants the polymeric diet group experienced nausea and four had diarrhoea. It is unclear if any participants in the mesalamine group had side effects. No serious side effects were reported in any of the studies.

The results for the outcomes assessed in this review are uncertain and no firm conclusions regarding the effectiveness and safety of enteral nutrition for maintenance of remission in Crohn’s disease can be drawn. More research is needed to determine the effectiveness and safety of using enteral nutrition as maintenance therapy in Crohn’s disease. Currently, there are four ongoing studies (estimated enrolment of 280 participants). This review will be updated when the results of these studies are available.