Elemental Diet

Elemental Diet

PEP Topic 
Radiation-Induced Diarrhea

An elemental diet is one that contains easily absorbable proteins in the form of amino acids, very minimal fat content, and easily absorbable vitamins and mineral content. Elemental diets have been used to maintain nutrition and reduce diarrhea (because absorption in the upper intestine can reduce stool volume) in patients with inflammatory bowel diseases. Use of an elemental diet formula has been studied in patients with cancer for its effect on radiation-induced diarrhea.

Effectiveness Not Established

Research Evidence Summaries

McGough, C., Wedlake, L., Baldwin, C., Hackett, C., Norman, A.R., Blake, P., … Andreyev, H.J. (2008). Clinical trial: Normal diet vs. partial replacement with oral E028 formula for the prevention of gastrointestinal toxicity in cancer patients undergoing pelvic radiotherapy. Alimentary Pharmacology & Therapeutics, 27(11), 1132–1139.

doi: 10.1111/j.1365-2036.2008.03665.x

Study Purpose:

To determine whether replacing a third of the normal diet with an elemental formula (E028) during the first three weeks of pelvic radiotherapy is feasible and effective in decreasing acute gastrointestinal (GI) toxicity

Intervention Characteristics/Basic Study Process:

Patients with a gynecologic, urologic, or lower GI malignancy who were scheduled to receive radical or adjuvant radiotherapy to the pelvis were randomized to receive either an elemental diet, which involved replacing one normal meal per day with the elemental formula E028 Extra, or no intervention for the first three weeks of treatment.

Sample Characteristics:

  • The study reported on 50 patients with a median age of 61.5 years.
  • The median age of patients in the intervention group was 62.5 years with a range of 29–79.
  • The median age of patients in the control group was 58 years with a range of 38–82.
  • The intervention group had 17 female and 8 male patients. The control group had 12 female and 13 male patients.
  • Patients had been diagnosed with gynecologic, urologic, or lower GI malignancies and were schedule to receive radical or adjuvant radiotherapy to the pelvis.


The study was conducted in an oupatient care setting in the United Kingdom.

Phase of Care and Clinical Applications:

Patients were undergoing the active treatment phase of care.

Study Design:

This was a prospective, randomized-controlled trial.

Measurement Instruments/Methods:

The Inflammatory Bowel Disease Questionnaire – Bowel specific sub-set (IBDQ-B), Vaizey Incontinence Questionnaire (VIQ), and Radiation Therapy Oncology Group (RTOG) tool were used.


  • Intake of the elemental formula was lower than the prescribed volume required to provide a third of caloric requirements. 
  • Bowel symptoms increased significantly in both groups as a result of pelvic radiotherapy. Symptom scores at weeks 3 and 5 were significantly higher than those at baseline for both groups. Changes in symptoms between baseline and week 3 were not significantly worse in the intervention group compared to the control group (p = 0.214).
  • No significant differences were found between groups at baseline (p = 0.632) or at any other timepoints (p = 0.151).


Patients in the intervention group exhibited poor compliance, ingesting only 65% of the proposed oral elemental formula. The intervention group did not experience a reduction in bowel symptoms or fecal calprotectin compared to the control group.


  • The sample size was small, with fewer than 100 patients.
  • The study was not blinded.
  • The intervention group included a greater proportion of patients with gynecologic malignancy, and the control group included a greater proportion of patients with urologic malignancy. Because the volume of small bowel in the targeted field and dose of radiotherapy differs according to cancer site, lack of stratification could have had an effect on outcome. Furthermore, results could have been affected by the fact that some of the patients with gynecologic cancers were receiving concomitant chemotherapy while those with urologic cancer were not.

Nursing Implications:

This study did not show a benefit to ingesting elemental formula. Orally ingested elemental formulae are known to be unpalatable, and the intervention group had poor compliance with consuming the proposed amount of formula.