The role of dietary long-chain n-3 fatty acids in anti-cancer immune defense and R3230AC mammary tumor growth in rats: influence of diet fat composition.

Abstract

We determined if long-chain n-3 fatty acids fed as part of a: (1) high polyunsaturated fat diet (currently recommended by several health agencies) or (2) low polyunsaturated fat diet (representative of that consumed by a large segment of the North American population) improved antitumor immune defense and inhibited tumor growth. Rats were fed one of four semi-purified diets (20% w/w fat) for 21 days pre- and 17 days post- R3230AC mammary tumor implantation. The polyunsaturated to saturated fatty acid (P/S) ratio was either 1 (high P/S diet) or 0.35 (low P/S diet). At each P/S ratio, diets provided long-chain n-3 fatty acids at 0 or 5% w/w of total fat. Long-chain n-3 fatty acids fed in a high P/S diet did not affect tumor growth or host immune responses. In contrast, feeding long-chain n-3 fatty acids in a low P/S diet increased natural killer cell cytotoxicity, splenocyte nitric oxide and interleukin-2 production, and the proportion of activated (CD25+) CD8+ and CD28+ cells, but did not significantly inhibit tumor growth. For both P/S diets, tumor cells from rats fed long-chain n-3 fatty acids had a higher n-3 content and n-3/n-6 ratio in phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. Furthermore, the magnitude of increase in n-3 fatty acid incorporation into tumor phospholipids was greater when fed in a low P/S diet. We demonstrated that the dietary P/S ratio significantly influences the effect of long-chain n-3 fatty acids on host immune responses and n-3 fatty acid incorporation into tumor cells. These findings warrant further consideration when designing dietary recommendations.

• Authors: Lindsay E Robinson, M Thomas Clandinin, Catherine J Field
• Journal: Breast cancer research and treatment (Breast Cancer Res Treat) Vol. 73 Issue 2 Pg. 145-60 (May 2002) ISSN: 0167-6806 [Print] Netherlands
• PMID: 12088117 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cytokines
• Dietary Fats
• Fatty Acids
• Fatty Acids, Omega-3
• Fatty Acids, Unsaturated
• Nitric Oxide

Topics

• Animals
• Breast Neoplasms (diet therapy, immunology, prevention & control)
• Cytokines (biosynthesis)
• Dietary Fats (administration & dosage, immunology)
• Fatty Acids (administration & dosage)
• Fatty Acids, Omega-3 (administration & dosage, immunology)
• Fatty Acids, Unsaturated (administration & dosage)
• Female
• Fluorescent Antibody Technique, Indirect
• Killer Cells, Natural (drug effects)
• Neoplasm Transplantation
• Nitric Oxide (biosynthesis)
• Random Allocation
• Rats
• Rats, Inbred F344
• Spleen (cytology, metabolism)
• Time Factors
• Treatment Outcome