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An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans

Amy E Griel12*, Penny M Kris-Etherton12, Kirsten F Hilpert12, Guixiang Zhao1, Sheila G West3 and Rebecca L Corwin12*

Author affiliations

1 Department of Nutritional Sciences, 126 S Henderson Bldg, The Pennsylvania State University, University Park, PA 16802, USA

2 The Huck Institutes of the Life Sciences, 201 Life Sciences Bldg, The Pennsylvania State University, University Park, PA 16802, USA

3 Department of Biobehavioral Health, 315 Health & Human Development East, The Pennsylvania State University, University Park, PA 16802, USA

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Citation and License

Nutrition Journal 2007, 6:2  doi:10.1186/1475-2891-6-2

Published: 16 January 2007

Abstract

Human, animal, and in vitro research indicates a beneficial effect of appropriate amounts of omega-3 (n-3) polyunsaturated fatty acids (PUFA) on bone health. This is the first controlled feeding study in humans to evaluate the effect of dietary plant-derived n-3 PUFA on bone turnover, assessed by serum concentrations of N-telopeptides (NTx) and bone-specific alkaline phosphatase (BSAP). Subjects (n = 23) consumed each diet for 6 weeks in a randomized, 3-period crossover design: 1) Average American Diet (AAD; [34% total fat, 13% saturated fatty acids (SFA), 13% monounsaturated fatty acids (MUFA), 9% PUFA (7.7% LA, 0.8% ALA)]), 2) Linoleic Acid Diet (LA; [37% total fat, 9% SFA, 12% MUFA, 16% PUFA (12.6% LA, 3.6% ALA)]), and 3) α-Linolenic Acid Diet (ALA; [38% total fat, 8% SFA, 12% MUFA, 17% PUFA (10.5% LA, 6.5% ALA)]). Walnuts and flaxseed oil were the predominant sources of ALA. NTx levels were significantly lower following the ALA diet (13.20 ± 1.21 nM BCE), relative to the AAD (15.59 ± 1.21 nM BCE) (p < 0.05). Mean NTx level following the LA diet was 13.80 ± 1.21 nM BCE. There was no change in levels of BSAP across the three diets. Concentrations of NTx were positively correlated with the pro-inflammatory cytokine TNFα for all three diets. The results indicate that plant sources of dietary n-3 PUFA may have a protective effect on bone metabolism via a decrease in bone resorption in the presence of consistent levels of bone formation.