EPA: preventive and therapeutic actions in relation to cancer risk and progression


In 2005, the Union of International Cancer Control launched “World Cancer Day.” Falling on February 4th each year, the aim is to bring awareness to cancer as a growing crisis, and to highlight the preventative steps needed to reduce cancer risk. Given that research suggests that around one-third of cancer deaths can be avoided through prevention and another third through early detection and treatment, cancer death rates could, theoretically, be reduced by two-thirds.

Certainly, the largest contributing factors to cancer involve lifestyle choices, with nearly 70% of all cancer deaths attributed to smoking, eating and drinking habits, or a ’sedentary lifestyle.’ Beneficial lifestyle and dietary changes, including eating at least 5 portions of fruits and vegetables a day, reducing intake of animal protein, animal fats, trans fats and processed foods, whilst also including 30 minutes of exercise 5-times a week, all add up to helping reduce the risk of developing cancer. Increasing fish intake, or replacing meat choices with fish, is also thought to be beneficial for reducing cancer risk. EPA, the long chain omega-3 associated with fish and fish oils, has been shown to have chemo-preventative effects in both cell culture and animal models. Consequently, the direct effect of EPA on cell division and cell death of tumour cells is now being investigated in humans. For example, EPA in supplement form has been shown to reduce both rectal polyp number and size in familial adenomatous polyposis, a particular aggressive form of colorectal cancer (West 2010).

However, EPA is not only being viewed as a potential colorectal cancer chemoprevention agent, more recently it has been shown that EPA supplementation can directly increase the radiosensitivity of tumour cells, indicating that supplementation could enhance the efficacy of irradiation during cancer treatment (Manda 2011). Furthermore, many cancer patients undergoing treatment, show substantial loss of body weight, fat and proteins, with significant inflammatory activity at the time of diagnosis. This wasting condition, known as cancer cachexia syndrome, reduces tumour response to treatment, and it is an indicator of poor prognosis. Correcting these nutritional deficits and modulating inflammation, are therefore paramount to the recovery of the patient. Individuals with cancer cachexia, undergoing cancer treatments, have been shown to respond well to EPA supplementation (Krznarić 2007). Indeed, doses of 1.5 g/day for a prolonged period of time to patients with advanced cancer is associated with an improvement in clinical, biological and quality of life (QoL) parameters (Colomer 2010). Given that EPA possesses such a diverse array of mechanisms, both preventive and therapeutic, how long will it be, I wonder, before its use is commonplace within the NHS?

References
1. West, N.J. et al. Eicosapentaenoic acid reduces rectal polyp number and size in familial adenomatous polyposis. Gut 59, 918-925 (2010).
2. Manda, K., Kriesen, S., Hildebrandt, G., Fietkau, R. & Klautke, G. Omega-3 Fatty Acid Supplementation in Cancer Therapy : Does Eicosapentaenoic Acid Influence the Radiosensitivity of Tumor Cells? Strahlenther Onkol (2011).doi:10.1007/s00066-010-2166-6
3. Krznarić, Z. et al. [Croatian guidelines for use of eicosapentaenoic acid and megestrol acetate in cancer cachexia syndrome]. Lijec Vjesn 129, 381-386 (2007).
4. Colomer, R. et al. N-3 fatty acids, cancer and cachexia: a systematic review of the literature. Br. J. Nutr 97, 823-831 (2007).

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