ONC: Dietary Supplements and Medical Food Supplements Containing Fish Oil (2013)


Bonatto SJ, Oliveira HH, Nunes EA, Pequito D, Iagher F, Coelho I, Naliwaiko K, Kryczyk M, Brito GA, Repka J, Sabóia LV, Fukujima G, Calder PC, Fernandes LC. Fish oil supplementation improves neutrophil function during cancer chemotherapy. Lipids. 2012; 47: 383-389.

PubMed ID: 22160495
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate whether supplementation with low-dose fish oil in cancer patients receiving chemotherapy after surgical tumor (mainly gastrointestinal) removal is able to improve the function of blood neutrophils.  

Inclusion Criteria:
  • Recent surgery to remove tumors at various sites, but predominantly gastrointestinal
  • About to begin chemotherapy.
Exclusion Criteria:

None specified, but presumed to be those who did not fit the inclusion criteria.

Description of Study Protocol:


Patients who recently underwent surgery for resection of tumors about to begin chemotherapy were recruited.  


Randomized prospective trial.


Patients were randomly allocated into two groups:

  • Control group: Received standard chemotherapy three times a week
  • Fish oil (FO) group: Received 2g per day FO in addition to the standard chemotherapy.

Statistical Analysis

  • Statistical analyses using data for both groups and time points were performed by ANOVA followed by a post-hoc Tukey test
  • Changes over time were compared between the groups using independent Student's T-tests
  • Differences were statistically significant when P<0.05. 
Data Collection Summary:

Timing of Measurements

At study entry, prior to start of chemotherapy, and eight weeks later, patients were weighed and a blood sample was taken for analysis.  

Dependent Variables

  • Neutrophils: Measured by taking venous blood samples to isolate polymorphonuclear cells (PMNC), mainly neutrophils. Cell viability and number were determined by Trypan Blue dye.
  • Fatty acid composition analysis of the PMNC was performed by fluorescence
  • Phagocytosis of PMNC was calculated with Zymosan staining
  • The volume of the lysosomal system of PMNC was assessed
  • Superoxide anion production by PMNC was measured
  • Hydrogen peroxide production by PMNC was measured
  • Weight was monitored. 

Independent Variables

The fish oil supplement (FO) of 2g daily which provided 0.3g EPA plus 0.4g DHA per day.

Description of Actual Data Sample:
  • Initial N: 38 patients were recruited (19 in the control group and 19 in the FO group)
  • Attrition (final N): All subjects completed the study
  • Age: Average age was 54.9±3.2 years in the control group and 53.8±2.4 years in the FO group.

Other Relevant Demographics

  • Male:female ratio: 10:9 in the control group; 12:7 in the FO group
  • Cancer site: 14 persons in each group had GI cancers; five in each group had cancers from other sites. 


  • Initial body weight: 69.5±3.6kg control group; 65.8±3.6kg FO group
  • Final body weight: 67.1kg±3.6 control group; 67.4±3.5kg FO group
  • There was no significant difference in age or body weight at study entry
  • Change in body weight was significantly different (P<0.002) with the control group losing 2.5±0.8kg and the FO group gaining 1.7±0.9kg.  


The study appeared to take place at Angelina Caron Hospital, Campina Grande do Sul, Brazil.

Summary of Results:

Key Findings

  • The fatty acid composition of PMNC did not change significantly over eight weeks in the control group
  • EPA and DHA in PMNC increased significantly in the FO group
  • Arachadonic acid (AA) decreased significantly after eight weeks of FO treatment, and the ratio of AA to EPA was significantly decreased. 

Content of Eicosapentaenoic Acid (EPA), Docosahexaenoic Acid (DHA) and Arachidonic Acid (AA) in PMNC from Control and Fish Oil (FO) Supplemented Patients at Study Entry (T0) and After Eight Weeks (T8)

  Control Group     Fish Oil Group    
  T0 T8 T8–T0 T0 T8 T8–T0
AA 6.70±0.26 7.24±0.16 0.54±0.25 6.43±0.20 5.15±0.30ab  -1.28±0.15d
EPA 0.48±0.10 0.38±0.90 -0.10±0.01 0.65±0.09 1.07±0.09ab 0.42±0.03d 
DHA 0.26±0.50 0.20±0.05  -0.06±0.05 0.27±0.03  0.51±0.06ab 0.25±0.07d 
AA/EPA 18.03±5.09 21.70±4.43 3.6±1.43 13.64±3.22 5.35±0.69ac -8.29±0.82d

a P<0.05 vs. control group at T8.

b P<0.05 vs. FO group at T0.

c P<0.001 vs. FO group at T0.

d P<0.05 vs. control group.

  • PMNC number tended to decline in the control group (P=0.06) but not the FO group
  • Phagocytosis of Zymosan by PMNC declined significantly in the control group with the average decrease of 45%
  • The FO group PMNC phagocytosis did not decline, but increased on average 15%
  • Phagocytosis by PMNC was greater in the FO group than in the control group after eight weeks
  • Uptake of neutral red did not decrease in the FO group, but did decrease about 40% in the control group
  • FO significantly increased superoxide production by PMNC
  • The FO group did not see a decrease in hydrogen peroxide production.

PMNC Number and Function in Control Group and Fish Oil Supplemented Patients at Study Entry (T0) and After Eight Weeks (T8)

  Control Group     Fish Oil Group    
  T0 T8 T8–T0 T0 T8 T8–T0 
PMNC (106 per ml) 8.75±1.18 6.05±0.79 -2.68±0.03 7.46±1.37 9.59±1.36c 2.13±0.05
Phagocytosis (Abs per 106 PMNC per ml) 0.62±0.05 0.34±0.02b -0.28±0.06 0.65±0.03 0.75±0.04de 0.09±0.04f
Neutral red uptake (abs per 106 PMNC per ml) 0.21±0.01 0.13±0.01a -0.08±0.01 0.22±0.01 0.23±0.01c 0.01±0.02f
Superoxide anion production (Abs per 106 PMNC per L) 0.45±0.03 0.45±0.03 0.01±0.48 0.46±0.03 0.58±0.03ce 0.13±0.03f
Hydrogen peroxide production (uM per 106 PMNC per ml) 56.65±2.47 47.01±2.20b -9.64±3.38  55.16±1.79 55.82±1.78d 0.66±2.09f

a P<0.05 vs. control at T0.

b P<0.001 vs. control at T0.

c P<0.05 vs. control at T8.

d P<0.001 vs. control at T8.

e P<0.05 vs. FO group at TO.

f P<0.05 vs. control group.

Other Findings

FO supplementation prevented the decline in PMNC number and function. This may lower the risk of infections during chemotherapy treatments. 

Author Conclusion:
  • FO supplementation at a rate of 2g per day for eight weeks in chemotherapy patients altered the fatty acid composition and function of blood PMNC, mainly neutrophils
  • This may represent an improvement in host defense and may be useful in preventing chemotherapy-induced decline in neutrophil number and function.
Funding Source:
Reviewer Comments:
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? ???
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? ???
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? ???
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? No
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???