Omega-3 fatty acid deficiency and osteoporosis

The essential polyunsaturated fatty acids (PUFAs) are divided into two main classes: n-3 (ω-3) and n-6 (ω-6). The most common source of n-6 fatty acids is linoleic acid (LA) which is found in high concentrations in various vegetable oils. Arachidonic acid (AA), the 20-carbon n-6 fatty acid, is largely obtained by the synthesis from LA in the body. The n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic (DHA) are found in fish and fish oils. PUFAs are precursors of a wide range of metabolites such as eicosanoids, prostaglandins and leukotrienes, which play critical roles in the regulation of a variety of biological processes including bone metabolism. A large body of evidence supports an effect of PUFAs on bone metabolism. This effect seems to be mediated by regulation of osteoblastogenesis and osteoclast activity, change of membrane function, decrease in inflammatory cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), modulation of peroxisome proliferators-activated receptor γ (PPARγ) and influence in nitric oxide secretion and synthesis. Animal studies have shown that a higher dietary omega-3/omega-6 fatty acids ratio is associated with more beneficial effects on bone health. Human studies suggest that omega-3 instead of omega-6 fatty acids have a positive effects on bone metabolism. In spite of increasing evidence, studies conducted in humans do not allow to draw a definitive conclusion on the usefulness of PUFAs in clinical practice. We wrote this chapter following the suggestions made in the article written by Van der Geer et al. [1]. © 2013 by Nova Science Publishers, Inc. All rights reserved.