Supplemental fish oil decreases urinary excretion of a marker of bone resorption in healthy adults

Background: Incorporation of fish oil (FO) into the diet of rodents has been shown to result in positive changes in bone health. Currently it is poorly understood if FO has the same effects on bone health in humans. The purpose of this study was to determine the effects of supplemental FO on levels of urinary Nterminal cross-linked telopeptide (NTx), which is a marker of bone breakdown, and how this is related to the morning levels of salivary cortisol and urinary excretion of interleukin 6 (IL-6). Methods: A total of twenty-eight females and twelve males(35 ± 13yrs; 69.1 ± 14.1kg; 29.4 ± 9.2% body fat; mean ± SD) participated in this study. All testing was conducted in the morning following an overnight fast. Baseline measurements of salivary cortisol were collected via passive drool and baseline measurements of urinary NTxand IL6 were collected from the second void of the day and corrected for creatinine excretion. After baseline testing, subjects were assigned randomly in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO) or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6wk of treatment. A treatment by time, repeated measures ANOVA was used to evaluate differences between groups over time, and a standard Pearson’s r was used to evaluate correlations. Additionally, within group pre-post differences were evaluated using a repeated measures t-test. For all analysis, the alpha level was set at p<0.05. Results: Compared to the SO group, there was a significant decrease in urinary creatinine corrected NTx excretion following FO treatment (SO = 17.5 ± 42.9 BCE/mM; FO = -11.3 ± 27.7 BCE/mM; p=0.02). There was also a tendency for urinary creatinine corrected IL-6 excretion (SO = -0.08 ± 1.18pg/mg; FO = -1.8 ± 3.8 pg/mg; p=0.08), and salivary cortisol (SO = 0.029±0.283 μg/dL; FO = -0.069 ± 0.144 μg/dL; p=0.13) to decrease following FO treatment.When analyzed independently, however, there was a significant pre-post reduction for salivary cortisol in the FO group (p=0.04), with no change in the SO group (p=0.68), as well as a significant reduction pre-post for urinary IL-6 in the FO group (p=0.05), with no change in the SO group (p=0.78). However, the change in urinary NTx concentrationwas not related to the change insalivary cortisol concentration( r=-0.017, p=0.9), or the change in urinary IL-6 concentration (r=-0.323, p=0.26). Conclusions: Six weeks of supplementation with FO in adults significantly decreased urinary NTx excretion, but this change was not related to changes in cortisol or IL-6. Comments This article is part of the supplement: Proceedings of the Eighth International Society of Sports Nutrition (ISSN) Conference and Expo This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/healthfac/54 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Required Publisher's Statement Original version is available from the publisher at: http://www.jissn.com/content/8/S1/P14 This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/healthfac/54 POSTER PRESENTATION Open Access Supplemental fish oil decreases urinary excretion of a marker of bone resorption in healthy adults Eric E Noreen, Josef Brandauer, Megan H MacNabb From International Society of Sports Nutrition: 8th Annual ISSN Conference and Expo Las Vegas, NV, USA. 24-25 June 2011 Background Incorporation of fish oil (FO) into the diet of rodents has been shown to result in positive changes in bone health. Currently it is poorly understood if FO has the same effects on bone health in humans. The purpose of this study was to determine the effects of supplemental FO on levels of urinary N-terminal cross-linked telopeptide (NTx), which is a marker of bone breakdown, and how this is related to the morning levels of salivary cortisol and urinary excretion of interleukin 6 (IL-6). Methods A total of twenty-eight females and twelve males(35 ± 13yrs; 69.1 ± 14.1kg; 29.4 ± 9.2% body fat; mean ± SD) participated in this study. All testing was conducted in the morning following an overnight fast. Baseline measurements of salivary cortisol were collected via passive drool and baseline measurements of urinary NTxand IL6 were collected from the second void of the day and corrected for creatinine excretion. After baseline testing, subjects were assigned randomly in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO) or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6wk of treatment. A treatment by time, repeated measures ANOVA was used to evaluate differences between groups over time, and a standard Pearson’s r was used to evaluate correlations. Additionally, within group pre-post differences were evaluated using a repeated measures t-test. For all analysis, the alpha level was set at p<0.05. Results Compared to the SO group, there was a significant decrease in urinary creatinine corrected NTx excretion following FO treatment (SO = 17.5 ± 42.9 BCE/mM; FO = -11.3 ± 27.7 BCE/mM; p=0.02). There was also a tendency for urinary creatinine corrected IL-6 excretion (SO = -0.08 ± 1.18pg/mg; FO = -1.8 ± 3.8 pg/mg; p=0.08), and salivary cortisol (SO = 0.029±0.283 μg/dL; FO = -0.069 ± 0.144 μg/dL; p=0.13) to decrease following FO treatment.When analyzed independently, however, there was a significant pre-post reduction for salivary cortisol in the FO group (p=0.04), with no change in the SO group (p=0.68), as well as a significant reduction pre-post for urinary IL-6 in the FO group (p=0.05), with no change in the SO group (p=0.78). However, the change in urinary NTx concentrationwas not related to the change insalivary cortisol concentration(r=-0.017, p=0.9), or the change in urinary IL-6 concentration (r=-0.323, p=0.26). Conclusions Six weeks of supplementation with FO in adults significantly decreased urinary NTx excretion, but this change was not related to changes in cortisol or IL-6. Funding Gettysburg College Research and Professional Development Grant and Genuine Health Corporation. Published: 7 November 2011 doi:10.1186/1550-2783-8-S1-P14 Cite this article as: Noreen et al.: Supplemental fish oil decreases urinary excretion of a marker of bone resorption in healthy adults. Journal of the International Society of Sports Nutrition 2011 8(Suppl 1):P14. * Correspondence: [email protected] Department of Health Sciences. Gettysburg College, Gettysburg PA, USA Noreen et al. Journal of the International Society of Sports Nutrition 2011, 8(Suppl 1):P14 http://www.jissn.com/content/8/S1/P14 © 2011 Noreen et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.