Eicosapentaenoic acid (EPA) and bone metabolism

Polyunsaturated fatty acids (PUFAs) are precursors of a wide range of metabolites, for example eicosanoids like prostaglandins and leukotrienes, which play critical roles in the regulation of a variety of biological processes, including bone metabolism. PUFAs can be classified into ω-6 and ω-3 groups. Eicosapentaenoic acid (EPA) is an ω-3 PUFA obtained in the human diet by the consumption of marine products. It is also found in the human breast milk. In the skeleton, there is evidence showing that altering the relative composition of dietary fatty acids can affect bone cell metabolism. Several studies have shown the benefits of EPA in bone. An EPA-enriched diet prevented loss of bone weight and strength in ovariectomized (OVX) rats fed with a lower calcium diet. It is also known to counteract weightlessness-induced bone loss by inhibiting NF-κB, a transcriptional activator of many genes, including some that lead to muscle atrophy and bone resorption. In another study, EPA was shown to be effective for diabetic osteopenia. Despite these benefits of EPA, a study indicated that supplementation of fish oil in large quantities and the associated increase in dietary fat content can lead to substantial degradation of the morphological and mechanical properties of cortical bone. This chapter will discuss the positive and negative effects of EPA intake in relation to bone metabolism as well as the possible mechanisms that explain such effects. In addition, the effect of ω-6/ω-3 ratios on calcium balance and bone as well as the recommended dietary intake of EPA will also be discussed. © 2012 Nova Science Publishers, Inc. All rights reserved.