Effect of essential fatty acids on circulating T cell subsets in patients with colorectal cancer

Targeting the tumor immune microenvironment with "nutraceuticals": From bench to clinical trials

The occurrence of immune effector cells in the tissue microenvironment during neoplastic progression is critical in determining tumor growth outcomes. On the other hand, tumors may also avoid immune system-mediated elimination by recruiting immunosuppressive leukocytes and soluble factors, which coordinate a tumor microenvironment that counteracts the efficiency of the antitumor immune response. Checkpoint inhibitor therapy results have indicated a way forward via activation of the immune system against cancer. Widespread evidence has shown that different compounds in foods, when administered as purified substances, can act as immunomodulators in humans and animals. Although there is no universally accepted definition of nutraceuticals, the term identifies a wide category of natural compounds that may impact health and disease statuses and includes purified substances from natural sources, plant extracts, dietary supplements, vitamins, phytonutrients, and various products with combinations of functional ingredients. In this review, we summarize the current knowledge on the immunomodulatory effects of nutraceuticals with a special focus on the cancer microenvironment, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of nutraceuticals for envisioning future therapies employing nutraceuticals as chemoadjuvants.

The Influence of Dietary Fatty Acids on Immune Responses

Diet-derived fatty acids (FAs) are essential sources of energy and fundamental structural components of cells. They also play important roles in the modulation of immune responses in health and disease. Saturated and unsaturated FAs influence the effector and regulatory functions of innate and adaptive immune cells by changing membrane composition and fluidity and by acting through specific receptors. Impaired balance of saturated/unsaturated FAs, as well as n-6/n-3 polyunsaturated FAs has significant consequences on immune system homeostasis, contributing to the development of many allergic, autoimmune, and metabolic diseases. In this paper, we discuss up-to-date knowledge and the clinical relevance of the influence of dietary FAs on the biology, homeostasis, and functions of epithelial cells, macrophages, dendritic cells, neutrophils, innate lymphoid cells, T cells and B cells. Additionally, we review the effects of dietary FAs on the pathogenesis of many diseases, including asthma, allergic rhinitis, food allergy, atopic dermatitis, rheumatoid arthritis, multiple sclerosis as well as type 1 and 2 diabetes.

Nutrition and the surgical patient: Triumphs and challenges

The understanding of the role of nutrition in the surgical patient has lead to major developments in the nutritional support of patients undergoing surgery. Reductions in morbidity by ensuring that patients receive optimal nutritional support can be achieved. Furthermore, the use of nutrients to modify immune, inflammatory and metabolic processes also offers new possibilities for reducing morbidity following major surgery. However, we are only at an embryonic stage in our understanding of how nutrients and nutrition affect the genome and this knowledge offers exciting possibilities in the future for modulating many key intracellular processes, particularly in the patient with cancer.

Nutritional and metabolic aspects of gastrointestinal cancer

The profound impact of nutrition and nutritional support on the development and clinical outcome of gastrointestinal cancer is undeniable. However, scientific investigation into this area is recent, and many questions remain unanswered. While the importance of 'good nutrition' is unchallenged, details relating to which patients should receive nutritional support, when they should receive it, and what type of support they should receive are not known. Recent prospective randomized clinical trials and meta-analysis have provided conflicting results. This review summarizes the results of the published studies that have addressed these issues, and provides specifics regarding the current role of nutritional support in clinical care, and the prospects for future research.

Enteral nutritional supplementation with key nutrients in patients with critical illness and cancer: a meta-analysis of randomized controlled clinical trials

OBJECTIVE

To conduct a meta-analysis of 11 randomized controlled trials comparing enteral nutritional support supplemented with key nutrients versus standard enteral nutritional support to determine effects on morbidity and mortality rates and hospital stay.

BACKGROUND DATA

Recent studies have shown that malnutrition occurs in up to 30% of patients undergoing gastrointestinal surgery, resulting in an increased risk of postoperative complications and death. With the realization that key nutrients can modulate inflammatory, metabolic, and immune processes, enteral nutritional regimens (supplemented with large amounts of key nutrients) have been developed for clinical use.

METHODS

Eleven prospective, randomized controlled trials evaluating 1009 patients treated with combinations of key nutrients (Impact, Immun-Aid) were evaluated. Outcome measures examined were the incidences of pneumonia, infectious complications, and death, and length of hospital stay. Meta-analyses were undertaken to obtain the odds ratio and 95% confidence interval for incidences of infectious complications, pneumonia, and death, and the weighted mean difference and 95% confidence interval for length of hospital stay.

RESULTS

The provision of nutritional support supplemented with key nutrients to patients with critical illness resulted in a decrease in infectious complications when compared with patients receiving standard nutritional support and a significant reduction in overall hospital stay. Similar results were documented in patients with gastrointestinal cancer. However, there were no differences between patient groups for either pneumonia or death.

CONCLUSIONS

This meta-analysis has demonstrated that nutritional support supplemented with key nutrients results in a significant reduction in the risk of developing infectious complications and reduces the overall hospital stay in patients with critical illness and in patients with gastrointestinal cancer. However, there is no effect on death. These data have important implications for the management of such patients.

The value of peri-operative nutrition in the sick patient

In summary, therefore, the provision of TPN to malnourished patients in the pre-operative period reduces the incidence of post-operative complications, but does not affect post-operative mortality. It is likely that the provision of nutrition by the enteral route is as effective as that by the parenteral route, and may have the extra benefit of resulting in a reduction in infectious complications when compared with patients receiving TPN. Furthermore, the use of enteral nutritional support in the post-operative period may also reduce both septic and major complications, but does not alter mortality. The use of specific combinations of nutrients appears to offer the greatest promise in the use of peri-operative nutritional support. The initial studies reported to date demonstrate reductions in post-operative morbidity, but again there are no benefits on mortality. However, further studies to determine the optimal combinations of nutrients for use in patients in the peri-operative period are urgently required.

Nutritional pharmacology and malignant disease: a therapeutic modality in patients with cancer

It is now established that certain nutrients have a significant effect on cellular metabolism and growth, tissue repair and regeneration, and modulation of host defences. So far, however, potential clinical benefits have been difficult to demonstrate. Nevertheless, the use of nutrients in combinations seems to have promise and may be associated with a reduction in infectious complications and length of hospital stay. Nutritional pharmacology in the future may be able to improve tumour response to chemotherapy and may minimize the metabolic effect of cachexia.