Restriction of Fresh Fruits and Vegetables

Restriction of Fresh Fruits and Vegetables

PEP Topic 
Prevention of Infection: General
Description 

A low microbial diet involves proper food and drink preparation and avoiding specific foods that may contain infection-causing organisms such as bacteria and fungi. Low microbial diets generally eliminate raw, unprocessed, and fresh fruits and vegetables, drinking tap water, and emphasize well-cooked foods and appropriate food handling to reduce cross contamination. Use of a low microbial diet has been recommended for prevention of infection in patients with cancer, but has not been extensively studied.

 

Effectiveness Unlikely

Research Evidence Summaries

DeMille, D., Deming, P., Lupinacci, P., & Jacobs, L. (2006). The effect of the neutropenic diet in the outpatient setting: A pilot study. Oncology Nursing Forum, 33, 337–343.

doi: 10.1188/ONF.06.337-343
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Study Purpose:

The study examined adherence to neutropenic diet and whether differences existed in rates of hospital admissions for febrile episodes and positive blood cultures between patients who adhered to the neutropenic diet and those who did not.

Intervention Characteristics/Basic Study Process:

Data collected at 6 and 12 weeks.

 

Sample Characteristics:

  • The study started with 28 participants; 23 completed the study.
  • Participants' age range was 33–67 years.
  • Patients had a wide range of diagnoses (except acute leukemia and HIV). Patients with acute leukemia and HIV were excluded.
  • Adult patients were eligible to be included if they were to receive chemotherapy associated with a high degree of neutropenia and were not being treated with colony-stimulating factors (CSFs).

Setting:

Outpatient cancer center

Measurement Instruments/Methods:

  • Rates of hospital admissions for febrile episode
  • Rates of positive blood culture

Questionnaires were developed to document demographic and medical variables as well as baseline knowledge of food safety and the neutropenic diet. Adherence to restrictions of the neutropenic diet was measured via self-report based on “yes” or “no” questions and a food-use questionnaire. The 6- and 12-week evaluations measured dietary adherence as a self-reported subjective statement with “yes” or “no” responses.

Adherence was verified via eight questions targeting specific points of the food safety aspects and diet restrictions covered in the instruction. Patients’ degree of difficulty in following the diet was assessed using Likert scales with four response choices. Patients were questioned regarding hospital admissions; however, the researchers verified all admission information via chart review. The instrument designed to collect information was developed specifically for this study to assess the major aspects of the neutropenic diet for food safety and the diet instructions as given to patients. Content validity was established by review of the tool by a multidisciplinary team.

A chart review was conducted post-treatment to validate self-reported medical information and verify neutropenia (i.e., absolute neutrophil count [ANC] less than 1,000/mm3). The chart review was reviewed by a multidisciplinary team for content validity.

Fisher’s exact test was used to analyze proportions between the groups.

Results:

30% of patients were noncompliant with the neutropenic diet.

No differences were found in the rate of febrile hospital admissions (per patient report and confirmed by chart review) and positive blood cultures between those patients who adhered to the neutropenic diet and those who did not.

Limitations:

  • Reports of whether patients adhered to a neutropenic diet were done by patients via a survey at 6- and 12-week intervals, which may have decreased the accuracy of self-reported data.
  • No randomization of patients was done. The convenience sample compared patients who were compliant with a neutropenic diet with patients who were noncompliant.
  • It was a small outpatient study in one setting; therefore, results cannot be generalized.
  • Content validity of the tool was established at the institution. Reliability was not tested.

Nursing Implications:

Of note, this study underscores the time spent for diet education, the question of appropriate content of diet education regarding food restrictions, and the difficulty adhering to diet requirements.

Gardner, A., Mattiuzzi, G., Faderl, S., Borthakur, G., Garcia-Manero, G., Pierce, S., & Estey E. (2008). Randomized comparison of cooked and noncooked diets in patients undergoing remission induction therapy for acute myeloid leukemia. Journal of Clinical Oncology, 26, 5684–5688.

doi: 10.1200/JCO.2008.16.4681
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Study Purpose:

This study was an evaluation of whether a diet including fresh fruits and vegetables increased the risk of infection in adult patients with cancer who were receiving induction chemotherapy for either acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) in a protective environment.

Intervention Characteristics/Basic Study Process:

Patients were randomized to either a “raw group” (n = 75) that was allowed a general diet including fresh fruits and vegetables or to a “cooked group” (n = 78) that was restricted to a low-microbial diet of all cooked food but no fresh fruit or vegetables. Patients remained in a protective environment from the initiation of induction chemotherapy until recovery of the absolute neutrophil count (ANC) over 500 mcl.  

Patients received routine antimicrobial prophylaxis with levofloxacin, valacyclovir, and an antifungal agent (itraconazole, voriconazole, or lipid amphotericin B).

Granulocyte–colony-stimulating factor was not used routinely.

Endpoints for the study were pneumonia, bacteremia, major infection, fever of unknown origin, and death.

Sample Characteristics:

  • A total of 153 patients were in the study.
  • Patients were all newly diagnosed with either AML or MDS and received induction chemotherapy in a protective environment (with a high-efficiency particulate air-filtered room).
  • Median age of the patients in the raw group was 63 years.
  • Median age of the patients in the cooked group was 64 years.
  • The most frequent chemotherapy used was cytarabine.
  • One-third of the new patients (n = 53) refused to participate in the study and were placed in a nonrandomized group. They stayed on the low-microbial diet and were given a separate consent for chart review.

Setting:

A single institution

Measurement Instruments/Methods:

The statistical design was the Bayesian multiple outcome design of Thall and Sung. The X2 or Kruskal-Wallis test was used to compare various pretreatment characteristics.

Results:

There was no statistically significant difference in the rate of infection, pneumonia, fever of unknown origin, or overall survival between the raw and cooked groups. A significantly higher rate of bacteremia was found in the raw group; however, the authors noted that most of the organisms responsible for the baceteremia were not of enteric origin.

The median number of days with an ANC less than 500 mcl was 20 days in the cooked group and 21 days in the raw group.
The median number of days with an ANC less than 100 mcl was 15 in the cooked group and 16 in the raw group.

  • Major infection rates: raw group: 35%; cooked group: 29% (p = 0.6)
  • Pneumonia rates: raw group: 5%; cooked group: 15% (p = 0.06)
  • Bacteremia or fungemia rates: raw group: 23%; cooked group: 9% (p = 0.03)
  • Fever of unknown origin rates: raw group: 36%; cooked group: 51% (p = 0.07)
  • Rate of infection or fever of unknown origin: raw group: 76%; cooked group: 87% (p = 0.09)
  • No significant difference existed in the rate of enteric organisms cultured from blood in either group (p = 0.12).
  • Survival rates: raw group: 61%; cooked group: 56%; non-randomized: 64%
  • Survival in all three groups was as expected in older patients with newly diagnosed AML or MDS.

Conclusions:

A diet that includes raw fruits and vegetables did not increase the risk of infection or death in patients with MDS or AML treated with remission induction chemotherapy in a protective environment when compared to a diet that restricted raw fruits and vegetables.

One strength of the study is that the sample was a population of high-risk patients who had an ANC less than 500 mcl for a median of 20 days. In comparison, patients with solid tumors treated with chemotherapy are at low risk for infection, and the patients that experience neutropenia generally have an ANC less than 500 mcl less than seven days. Because this study demonstrated an absence of efficacy of the low-microbial diet in high-risk patients; it is unlikely to be of benefit in low-risk patients with a much shorter duration of neutropenia. However, further research is warranted to confirm the findings in other populations of neutropenic patients.

Limitations:

  • The study was done at a single institution.
  • The study was conducted with patients in a protective environment, and patients were treated routinely with prophylactic antimicrobial agents. Therefore, findings are not generalizable to outpatients, patients cared for in non-protective environments, or patients not treated with prophylactic antimicrobial agents.
  • The rates of infection and death were the same between study groups; however, the rate of bacteremia was significantly higher in the raw group. Although the incidence of bacteremia was higher in the raw group, the authors reported that a substantial part of the difference reflected isolation of organisms not resident in the gut; the presence of such organisms would not be expected to be influenced by cooking of fruits and vegetables. In addition, the incidence of fever of unknown origin was higher in the cooked group, suggesting that some cases of bacteremia in the cooked group were not identified.

Moody, K., Finlay, J., Mancuso, C., & Charlson, M. (2006). Feasibility and safety of a pilot randomized trial of infection rate: Neutropenic diet versus standard food safety guidelines. Journal of Pediatric Hematology/Oncology, 28, 126–133.

doi: 10.1097/01.mph.0000210412.33630.fb
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Study Purpose:

The purpose of the study is to demonstrate a safe and feasible methodology to evaluate the infection rate in pediatric patients with cancer randomized to the neutropenic diet or the U.S. Food and Drug Administration (FDA)-approved food safety guidelines.

Intervention Characteristics/Basic Study Process:

Pediatric patients (aged 1–21 years) undergoing myelosuppressive chemotherapy were randomized to receive a neutropenic diet or a diet based on the FDA food safety guidelines (emphasis on safe handling and cooking). Patients were enrolled during one cycle of chemotherapy.

Primary outcome was febrile neutropenia.  
Secondary outcome was adherence and diet tolerability.

 

Sample Characteristics:

  • The sample size was 19.
  • The two groups of participants were matched on all variables except history of febrile neutropenia.

Setting:

Two hospitals in New York

Study Design:

Prospective, randomized, controlled pilot study

Measurement Instruments/Methods:

  • Infection was measured with hospital admission data for febrile neutropenia.  
  • Localized infection (along with an ANC less than 500 cells/mm3) also was included.  
  • Dietary adherence measured by 24-hour diet recall.
  • Student t test measured differences between the groups.

Results:

No statistically significant differences in infection was found between the two groups.  
Four patients on each arm developed febrile neutropenia.  
Adherence rate was 94% for neutropenic diet and 100% for FDA-approved food safety guidelines.

Limitations:

  • Small sample size.  
  • Difficulty adhering to the neutropenic diet was reported.  
  • Adherence measured by 24-hour diet recall.

Van Tiel, F.H., Harbers, M.M., Terporten, P.H.W., van Boxtel, R.T.C., Kessels, A.G., & Voss, G.B. (2007). Normal hospital and low-bacterial diet in patients with cytopenia after intensive chemotherapy for hematologic malignancy: A study of safety. Annals of Oncology, 18, 1080–1084.

doi: 10.1093/annonc/mdm082
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Intervention Characteristics/Basic Study Process:

Adult patients with acute leukemia receiving remission-induction chemotherapy.
Patients received either antibacterial prophylaxis (AP) and low-microbial diet (LBD) or AP and normal hospital diet (NHD) to prevent infections.

Patients were randomized into two groups.

  • Patients receiving antibiotic prophylaxis (AP) and low-bacterial diet (LBD)
  • Patients receiving AP and normal hospital diet (NHD).  

AP included ciprofloxacin 500 mg every 12 hours and oral fluconazole 50 mg every 24 hours and was started before initiation of chemotherapy and discontinued when leukocyte counts recovered to 1,000/mm3 or higher.

Sample Characteristics:

  • The total sample size was 20 (15 men and 5 women).
  • All were patients with acute leukemia undergoing remission-induction chemotherapy.

Study Design:

Randomized, controlled pilot study

Measurement Instruments/Methods:

  • Infection was measured by gastrointestinal tract colonization with yeast or gram-negative bacilli or fever higher than 38ºC.
  • Stool was measured daily for bacterial colonization.  
  • A Student's t test compared degree of colonization between the two groups. Differences at cycle-specific points in time were evaluated with a multivariate analysis of variance (MANOVA). Differences in temperature were measured by the Fisher’s exact test.

Results:

No statistically significant differences were found between the two groups for rates of infection.

Limitations:

  • The small pilot study and sample size were inadequate to observe significant differences between the study groups.
  • The study did not measure whether patients were adherent to their assigned diets.  
  • Randomization could not create two equal groups.  
  • Patients received AP.
  • Results cannot be generalized because of the small sample size.

Systematic Review/Meta-Analysis

van Dalen, E.C., Mank, A., Leclercq, E., Mulder, R.L., Davies, M., Kersten, M.J., & van de Wetering, M.D. (2012). Low bacterial diet versus control diet to prevent infection in cancer patients treated with chemotherapy causing episodes of neutropenia. Cochrane Database of Systematic Reviews, 9, CD006247.

doi: 10.1002/14651858.CD006247.pub2
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Purpose:

To determine the efficacy of a low bacterial diet (LBD) versus a control diet in preventing the occurrence of infection and reducing related mortality in patients with cancer receiving immunosuppressive chemotherapy.

Search Strategy:

Databases searched were the Cochrane Central Register (CENTRAL), DARE, PubMed, EMBASE, and CINAHL, as were conference proceedings from multiple professional groups.

Included in the study were patients with cancer receiving chemotherapy causing episodes of neutropenia, use of an LBD versus a control diet, with an LBD defined as any diet intended to reduce the ingestion of bacterial and fungal contaminants by exclusion of uncooked fruits and vegetables, cold cuts, undercooked eggs and meat, unsterilized water, unpasteurized milk products, and soft cheeses. The control diet was any other diet.

Children younger than 1 year were excluded from the study.
 

Literature Evaluated:

Six hundred nineteen total references were retrieved.

Risk of study bias was evaluated using the Cochrane Handbook for Systematic Reviews of Interventions.

 

Sample Characteristics:

  • After exclusion, the final number of studies examined was three.
  • The sample range across studies was 19 to 153.
  • Samples included patients treated with remission induction chemotherapy for acute myeloid leukemia, high-risk myelodysplastic disease, or acute lymphoblastic leukemia.
  • One study had a pediatric population.

Phase of Care and Clinical Applications:

  • Patients were undergoing the active antitumor treatment phase of care.
  • The study has clinical applicability for pediatrics.

Results:

Included studies had different definitions of infection rate and different outcomes measured and defined. Blinding and selection bias were problems in the study design, and only one study provided explicit data on the use of empirical antibiotics and antimycotics. Data could not be pooled for meta-analysis. In all three studies, there was no significant difference in outcomes between groups.

Conclusions:

There is currently no strong evidence demonstrating the need or effectiveness of LBDs, and due to differing outcome measures, diets used and cointerventions for prophylaxis pooling of results was not possible. No firm conclusions can be drawn, and no recommendations for clinical practice are made.

Limitations:

  • Small number of studies
  • Various study design limitations and risks of study bias

Nursing Implications:

The results suggest that no firm conclusions can be made about the usefulness of an LBD and that there is no strong evidence to show the effect. Additional well-designed research in this area would be helpful.


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