Omega-3 supplementation improved immune function in GI cancer patients post-surgery, says meta-analysis

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Short-term omega-3 supplementation in postsurgical gastrointestinal cancer patients improved post-operative indicators of immune function, inflammation, and other postoperative outcomes, according to meta-analysis¹ of 16 randomized controlled trials. This is significant, the researchers point out, because gastrointestinal cancer patients often have a poor prognosis due to malnutrition and poor immune function manifesting from a lack of appetite, digestive problems, and malabsorption of nutrients. This makes the likelihood of postoperative secondary infections and other complications much higher.

The total number of subjects included in the meta-analysis was 1008: 506 in the omega-3 group and 502 in the control group. Results of the meta-analysis showed that cellular immune function increased in response to omega-3 supplementation on the sixth day post-surgery as measured by levels of T lymphocyte subsets CD3+, CD4+, CD8+, and CD4+/CD8+. These cells work together to produce an active, but balanced, immune response. CD4+ T cells, for example, promote B-cell proliferation to induce antibody production as well as play a mediating role in inflammation. CD8+ T cells, on the other hand, inhibit antibody secretion and T cell proliferation.

The level of immunoglobulins, which are proteins that act as antibodies, also went up on the sixth day post-surgery during omega-3 supplementation. Levels of inflammatory cytokines went down as well-specifically, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and C-reactive protein (CRP), all of which play an important role in the body’s response to tissue injury and inflammation in early trauma. Researchers explain that reducing the release of TNF-alpha and IL-6 can reduce damage to the immune system, thus improving immune function. CRP levels, they explain further, show rapid and sensitive change to acute trauma and infection typically increasing 4 to 12 hours after surgery, peaking 24 to 72 hours after surgery and eventually returning to baseline 14 days after surgery. The meta-analysis showed that the control group had significantly higher levels of CRP six days after surgery.

The meta-analysis also found that lymphocytes, a type of white blood cell, were significantly higher in the omega-3 group, improving the body’s defenses. These physiological changes translated into a real-life benefit, as there was a significantly lower incidence of complications from infection in the omega-3 group.

These are positive results that require further research since the meta-analysis has its limitations. For example, the meta-analysis only included Chinese patients and may not be generalizable to other ethnic populations, and other factors like the quality of care differences between hospitals may have produced different outcomes.

References:

1. Zhao Y et al. “Effect of ω-3 polyunsaturated fatty acid-supplemented parenteral nutrition on inflammatory and immune function in postoperative patients with gastrointestinal malignancy.” Medicine, vol. 97, no. 16. (April 2018).