n-3 PUFAs favour immunity and lessen inflammation in patients undergoing surgery for GI cancer
Surgical resection is the principal treatment in early stages of gastro-intestinal (GI) cancer, but involves the risk of developing several complications, including malnutrition, tumour-induced immunosuppression, surgical stress and inflammation. Of these complications, which affect clinical outcomes, length of hospitalisation and cost, malnutrition has the biggest impact on prognosis.
The clinical guidelines of the American Society for Parenteral and Enteral Nutrition (ASPEN) recommend that patients with large tumours undergoing surgery start nutritional support (with various nutrients to strengthen the immune system) 5 to 7 days before the operation and continue it afterwards.
Reports have been published on how omega-3 polyunsaturated fatty acids (n-3 PUFAs) can help improve immune status and reduce inflammatory response in GI cancer patients undergoing surgery and they seem to be a better option in postoperative nutritional treatment than isocaloric nutrition. The results of the meta-analysis recently carried out by Yu et al. shows that n-3 PUFAs are a beneficial dietary supplement, as they significantly reduce the level of inflammation (reducing concentrations of inflammatory cytokines such as interleukin IL-2, IL-6 and tumour necrosis factor-alpha (TNF-α), also reducing the presence of c-reactive protein (CRP)), strengthen immune function and reduce hypoalbuminemia. The immunomodulating activity affects T-cell activation and cytokine production and there is also evidence that both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) might have antineoplastic properties. The results of the meta-analysis show that, in GI cancer surgery patients n-3 PUFAs increase levels of CD4+ and CD4+/CD8+ T-cells and can reduce the level of CD8+, which would lead to an improvement in immune response and, therefore, favour rehabilitation after surgery (shortening hospitalisation times). The meta-analysis included 9 controlled, randomised trials, with a total of 623 participants. Compared to the isocaloric diet, the diet with n-3 PUFA reduced levels of CRP (P < 0.05) and IL-6 (P < 0.01) and increased levels of albumin, CT3+ and CD4+ T-cells and the CD4+/CD8+ ratio (P < 0.05); levels of CD8+ T-cells also dropped compared to the isocaloric nutritional regimen (P < 0.0001).
This study shows that n-3 PUFA is effective in improving nutritional status and immune function in GI cancer surgery patients.
Yu J, Liu L, Zhang Y et al. Effects of omega-3 fatty acids on patients undergoing surgery for gastrointestinal malignancy: a systematic review and meta-analysis. BMC Cancer. 2017 Apr 14;17(1):271.