Preface

Despite the known and varied health benefits of n–3 fatty acids, current US intakes are lower than national (1-6) and international (7) recommendations, and considerable confusion exists about safe and biologically active sources of n–3 fatty acids. Confusion also exists about how the dietary recommendations for these nutrients are set; in particular, it is not clear whether n–3 fatty acids are best obtained from sources containing preformed eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). It is also not clear how intakes of n–6 and n–3 fatty acid precursors affect the interconversion to biologically active forms.

The symposium "n–3 Fatty Acids: Recommendations for Therapeutics and Prevention" was convened by the Institute of Human Nutrition of Columbia University on 21 May 2005. The goals of the symposium were 1) to increase awareness among health professionals of the biological benefits of n–3 fatty acids and the adverse effects of inadequate n–3 fatty acid consumption by large segments of the population and 2) to translate basic science findings related to the specific long-chain n–3 fatty acids EPA and DHA into strategies for the prevention of disease or improved health in clinical practice and public health settings. The proceedings of the symposium and a workshop that followed are summarized in the present journal supplement.

In reviewing the literature, the discussants were asked to assess whether single n–3 fatty acids [-linolenic acid (ALA), EPA, or DHA] or their combination were responsible for the biological effects and, where possible, to provide recommendations for intake of a specific n–3 fatty acid or a combination of n–3 fatty acids. Suboptimal intake of DHA, for example, is a significant public health issue for persons of all ages. Adequate consumption of DHA has ramifications throughout the life cycle, ranging from effects in women of childbearing age and developing fetuses to those in the very old and including effects on the development of heart disease and dementia. The discussants provided a comprehensive overview of how suboptimal intake of n–3 fatty acids affects health at every stage of the life cycle.

Collectively, higher intakes of n–3 fatty acids could affect many heath issues, including the following:

• pregnancy outcomes (postpartum depression, pregnancy duration);
  
• cognitive development and learning in infants and children;
  
• visual development;
  
• immune and inflammatory responses;
  
• rheumatoid arthritis, ulcerative colitis, Crohn disease, eczema, asthma, and type 1 diabetes;
  
• metabolic syndrome, type 2 diabetes, and obesity;
  
• cardiovascular disease and lipid metabolism;
  
• neurologic degeneration (dementia, including Alzheimer disease); and
  
• mental health and mood disorders.
  

The conference and workshop and these proceedings aim to assist researchers and health professional to

• access, interpret, and utilize the most current dietary recommendations regarding n–3 fatty acids and make informed recommendations for individual and population consumption of specific n–3 fatty acids (ALA, DHA, and EPA);
  
• appreciate the scientific and epidemiologic basis of the development of current n–3 fatty acid recommendations and distinguish between different functions of the different fatty acids;
  
• understand the roles of DHA that affect the health of the developing fetus and infant;
  
• explain current gaps in knowledge of and intake of DHA that affect women's health from puberty through menopause and into old age;
  
• compare and contrast the human distribution, biological activity, safety, toxicity, and variability of different dietary sources of n–3 fatty acids; and
  
• present strategies for improving public health through interventions targeted at specific populations.
  

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