Increased intakes of omega-3 fatty acids may reduce skin cancer risk

Regular consumption of omega-3 fatty acid rich fish oils could help to protect against skin cancer by blocking the sun’s ability to suppress immune responses, suggests a new UK study.

In the randomized controlled trial, 79 healthy participants received four grams of omega−3 polyunsaturated fatty acids (70% eicosapentaenoic acid plus 10% docosahexaenoic acid) or a control lipid daily for three months (1). After they were exposed to the equivalent of eight, 15 or 30 minutes of summer midday sun
(in the UK) using a light machine that provided solar-simulated ultraviolet radiation (SSR), suppression of cutaneous cell-mediated immunity (CMI) was measured. The study results showed that immunosuppression reached 43% at the highest SSR dose used. However, immunosuppression was 50% lower in participants who took the omega-3 fatty acids and were exposed to 8 and 15 minutes of SSR, compared with the control group. No significant difference was measured for those in the 30 minute groups.

The researchers concluded that a continuous low level of chemo-prevention from taking omega-3 could reduce the risk of skin cancer over an individual’s lifetime. The findings add to the evidence from animal trials (2) and epidemiologic surveys (3) that omega-3 fatty acids are a potential nutrient to protect against skin cancer. Sunlight-induced suppression of the immune system, known as photo-immunosuppression, is known to affect the body’s ability to fight skin cancer and infection. Omega-3 fatty acids are readily taken up into human skin where they may influence UVR-induced immunosuppression through several mechanisms, including the effect on membrane fluidity, signal transduction, transcription-factor activation, and soluble mediator production.

The scientists noted their findings may be important in the battle against skin cancer because previous research has shown that sunscreens are often applied inadequately and only worn during holiday periods. However, omega-3 fatty acids would not be a substitute for sunscreen and physical protection; they should be regarded as an additional small measure to help protect skin from sun damage.

1. Pilkington S. M. et al. Randomized controlled trial of oral omega-3 PUFA in solar-simulated radiation-induced suppression of human cutaneous immune responses. Am J Clin Nutr. 2013; 97(3):646–652.
2. Moison R. M. and Beijersbergen Van Henegouwen G. M. Dietary eicosapentaenoic acid prevents systemic immunosuppression in mice induced by UVB radiation. Radiat Res. 2001; 156:36–44.
3. Hakim I. A. et al. Fat intake and risk of squamous cell carcinoma of the skin. Nutr Cancer. 2000; 36:
   155–162.