Are dietary recommendations for the use of fish oils sustainable?

633 P eople in developed countries have been encouraged in recent years to increase their intakes of fatty fish by at least 2–3-fold. The goal is to consume adequate amounts of the long-chain polyunsaturated omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for optimal health and prevention of major chronic diseases. Health agencies now recommend that the current average intake of 100 mg/d of omega-3 fish oils, reported in the National Health and Nutrition Examination Survey III, 1 should be raised to 1000 mg (2 servings of oily fish) per week for prevention of chronic disease. 2 Amounts of 250 mg/d 3 to as high as 1000 mg/d are suggested for secondary prevention of coronary artery disease, and amounts of 2000–4000 mg/d are recommended for the management of elevated triglyceride levels. 4 The main problem with this advice is that, even at current levels of fish consumption, fisheries globally have reached a state of severe crisis (Figure 1). 5–8 Already, the demand from affluent and developing economies, particularly newly affluent China, cannot be met by the world's fisheries. 6 Moreover, declining catches are increasingly diverted toward affluent markets rather than local ones, with dire consequences for the food security of poorer nations, islands and coastal communities. 9 The collapse of global fish stocks and its socioeconomic effects are therefore incongruent with the current recommendations to consume more fish oils. In this article, we examine the questions that arise from this dilemma. What is the evidence that fish oils have a role in disease prevention? How limited are supplies of fish oil? What are the environmental and socioeconomic consequences of an increase in fish consumption in developed countries? Are there viable alternative sources of omega-3 fatty acids? If there are, should we focus on developing these sources as a commercially available solution? Most of the focus on fish oils has been related to their use in preventing coronary artery disease, which has the most evidence to support it. That evidence includes both epidemio-logic cohort studies and randomized controlled trials. Cohort studies are seen as largely supportive of the assumption of benefit from fish oils. 3,10 However, fish eaters generally have healthier lifestyles than the rest of the population. They exercise more, smoke less and have better diets. 11–13 Controlling for these variables may not allow investigators to fully understand the independent influences of any one factor. Similarly, populations with …