Consumption of fish or omega-3- fatty acids from fish reduces coronary heart disease mortality, the leading cause of death in developed nations. The precise way in which fish provides benefit is not fully understood. This is important as fish and fish oils consist of a complex mixture of fatty acids and micronutrients that could individually, or collectively, be responsible for the beneficial effects. Aquaculture in Scotland is playing an increasingly important role in the provision of fish for human consumption, but issues with sustainability are requiring aquaculture to replace traditional fish oil and meal in formulated fish diets by oil from more sustainable sources, which may affect the levels of beneficial omega-3 fatty acids (EPA and DHA) and other components in fish. We will investigate the health effects of consuming two portions oily fish (Scottish farmed salmon) per week (current UK recommendation) using fish raised on different feeding regimes.