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


Gogos GA, Ginopoulos P, Zoumbos NC, Apostolidou E, Kalfarentzos F. The Effect of Dietary Omega 3 Polyunsaturated Fatty Acids on T-Lymphocyte subsets of patients with solid tumors. Cancer Detection and Prevention. 1995; 19(5): 415-417.

PubMed ID: 7585727
Study Design:
Non-Randomized Controlled Trial
C - Click here for explanation of classification scheme.
Quality Rating:
Negative NEGATIVE: See Quality Criteria Checklist below.
Research Purpose:

Does dietary polyunsaturated fatty acids have an effect on T-lymphocyte subpopulations and natural killer cells of patients with solid tumors?

Inclusion Criteria:
  • Solid tumors
  • Malnourished, though no specifics
  • Not currently receiving treatment with chemotherapy or immunomodulating agents

Exclusion Criteria:

Not indicated

Description of Study Protocol:


Recruitment procedures not indicated.


  • Approved by Hospital Ethics Committee
  • Both malnourished and controls received 18 grams of Fish oil per day for 40 days
  • Peripheral blood leukocytes and lymphocytes, Tcells, T-helper cells, T-suppressor cells, helper:suppressor cell ratio(H/S) and NK cells were measured before fish oil supplementation and for 40 days during fish oil supplementation.
  • Monoclonal antibodies and immunofluorescence microscopy was used to study the lymphocyte subsets.


  • 18 grams of Fish oil per day for 40 days.

Statistical Analysis

  • Mean value +/- standard deviation
  • Student's t test for statistical analysis


Data Collection Summary:

Timing of Measurements

  • Measurements were provided before and after 40 consecutive days of supplementation of 18 grams of fish oil

Dependent Variables

  • Peripheral blood leukocytes and lymphocytes
  • T-cells (total) 
  • T-Helper (CD-4) cells
  • T-Suppressor (CD-8) cells
  • Helper:suppressor cell ratio (H/S)
  • NK cells

Other dependent variables include: Karnofski value, total or partial response, survival, body weight, serum albumin or serum transferrin (although details of testing and actual values not provided in the study).

Independent Variables

  • 18 grams of fish oil

Control Variables



Description of Actual Data Sample:

Initial N: 20 malnourished patients, 12 males and 8 females

10 controls (sex not indicated)

Attrition (final N): N=20

Age: mean age of 58.5 years (42-65)

Controls: 61.5 years (range 44-76 years)

Ethnicity: Not indicated

Other relevant demographics: N=12 metastatic gastrointestinal cancer patients, N=6 lung cancer patients, N=2 breast cancer patients

Anthropometrics Not indicated

Location: Does not indicate where patients received treatment other than fish oil came from Athens Greece and researchers are from Patras University, Patras, Greece


Summary of Results:

Table 1

Percentage Numbers (% of Blood Lymphocytes) of T-Lymphocytes Subpopulations including Total T Cells, Helper(CD4) and Suppressor (CD8) T Cells, Helper: Suppressor(H/S) Cell Ratio, and NK Cells of Controls and Cancer Patients, Before and 40 Days into Dietary Supplementation with Omega-3 Fatty Acids

T-Cell Subsets

Controls (%)

Cancer Patients (%)


Cancer Patients(%)




65.3 +/-14.6


58.7 +/-13.3 52.0 +/-13.8



44.7 +/-10.8 36.5 +/-11.2 35.4 +/-12.7


20.1 +/-8.7


29.7 +/-9.4


18.9 +/-7.5a



2.17 +/-0.51

1.20 +/-0.26

1.74 +/-0.4 a



13.2 +/-3.9

11.4 +/-3.3

13.3 +/-4.5

a denotes p<0.05

Values are expressed as mean +/- SD.

Table 2

Absolute Numbers (per mm3) of Blood Leukocytes, Lymphocytes Total T Cells, Helper (CD4) and Suppressor (CD8) T Cells, and NK Cells of Controls and Cancer Patients, Before and 40 Days into Dietary Supplementation with Omega-3 Fatty Acids

Cell Numbers


Cancer Patients


Cancer Patients




6890 +/-1340 7190 +/-1645 5690 +/-1352



2411 +/-592 2158 +-543 1991 +/-388
Total T cells

1575 +/-352


1267 +/-287 1037 +/-275


1078 +/-260


787 +/-241


705 +/-253


484 +/-209


641 +/-202

376 +/-149a


318 +/-94


246 +/-71

265 +/-90

a denotes p < 0.01

Values are expressed as mean +/- SD.


Other Findings

  • Absolute and percentage numbers of total T cells, helper T cells and NK cells before and after omega-3 supplementation were not significantly different
  • No differences found in Karnofski value, total or partial response, and survival  in patients receiving supplementation vs those were who not receiving supplementation
  • Body weight, serum albumin, and serum transferrin were similar in all patients before and 40 days after dietary supplementation with Omega-3 fatty acids.
Author Conclusion:
  • Omega-3 Fatty Acid supplementation may provide some beneficial effects on the immune system of malnourished cancer patients.
  • Most significant effects were noted as an increase in helper:suppressor T-cell ratio in patients with gastrointestinal and lung cancer as a result of a significant decrease in suppressor T-cells.
  • Omega-3 fatty acids may have an inhibitory effect on on immunosuppressive substances such as PGE2 which may indirectly have an impact on suppressor T cells.
Funding Source:
Reviewer Comments:
  • Small sample size
  • Short term study
  • Mixed cancer sites
  • No mention of dietary intake prior to and during study
  • No mention of how patients were characterized as malnourished
  • Compliance to intervention was not measured
  • No mention of drop out rate
  • Clinical data representing nutritional status was not presented
  • No mention of timing of fish oil provided on daily basis
  • No blinding
  • No control product



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? No
2. Was the selection of study subjects/patients free from bias? No
  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? No
  2.2. Were criteria applied equally to all study groups? No
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? No
  4.1. Were follow-up methods described and the same for all groups? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? N/A
  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.) N/A
  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? No
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? ???
  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? N/A
  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? ???
  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? ???
  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? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? No
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)? ???
  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? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? ???
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? ???
  10.2. Was the study free from apparent conflict of interest? ???