June 19, 2018

A review and meta-analysis appearing in the April 2018 issue of the journal Medicine concluded that supplementation with omega-3 polyunsaturated fatty acids early in the treatment of gastrointestinal cancer can boost immune function and reduce inflammation.

For the meta-analysis, Yajie Zhao, MD, and Chengfeng Wang, MD, of the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing selected 16 randomized controlled trials that included a total of 1,008 patients who underwent surgery for gastrointestinal cancer. Participants were given a postoperative parenteral (administered intravenously) nutrition formula consisting of an emulsion of medium-chain and long-chain triglycerides for up to seven days. Of the 1,008 patients, 506 also received an emulsion that contained omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Postoperative outcomes examined in the studies included the markers of cellular immune function CD3+, CD4+, CD8+, and CD4+:CD8+ ratio; markers of humoral (extracellular) immune function that included immunoglobins A, M and G (IgA, IgM and IgG), and lymphocyte (a type of white blood cell) counts; the inflammation markers interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP); and postoperative incidence of infections.

Subjects who received omega-3 fatty acids had improved cellular immunity as indicated by higher CD3+, CD4+ and CD4:CD8+ ratios in comparison with the control group. Omega-3 fatty acid supplementation was also associated with improved humoral immunity as revealed by higher levels of IgA, IgM and IgG and greater lymphocyte counts compared to the controls. Markers of inflammation were lower in the omega-3 supplemented subjects than among the controls, and postoperative infections were reduced.

Drs Zhao and Wang note that traditional fat emulsions’ main component is omega-6 fatty acids, which can increase inflammation and impair immune function. In contrast, omega-3 fats improve immune function and inhibit the inflammatory response. "Studies have shown that changes in immune function play an important role in host tumor recurrence or metastasis, and low immune function can cause accelerated diffusion of tumor cells,” they remark. “Therefore, it is of great clinical significance to improve the nutritional status and the immune function of such patients.

"The result of this meta-analysis confirmed that early intervention with omega-3 fatty acid emulsion in gastrointestinal cancer can not only improve the postoperative indicators of immune function, reduce inflammatory reaction, and improve the postoperative curative effect but also improve the immune suppression induced by conventional parenteral nutrition or tumor,” they conclude. “Therefore, postoperative patients with gastrointestinal cancer should add omega-3 unsaturated fatty acids in their parenteral nutrition formula."