title: An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans.
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) alpha-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 TNFalpha 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.
authors.affiliation: Department of Nutritional Sciences, 126 S Henderson Bldg, The Pennsylvania State University, University Park, PA 16802, USA. aeg126@psu.edu
authors.forename: Amy E
authors.initials: AE
authors.lastname: Griel
authors.forename: Penny M
authors.initials: PM
authors.lastname: Kris-Etherton
authors.forename: Kirsten F
authors.initials: KF
authors.lastname: Hilpert
authors.forename: Guixiang
authors.initials: G
authors.lastname: Zhao
authors.forename: Sheila G
authors.initials: SG
authors.lastname: West
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Corwin
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D001862:Bone Resorption / Q000188:drug therapy*; D024042:Collagen Type I / Q000097:blood; D018592:Cross-Over Studies; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D004311:Double-Blind Method; D005227:Fatty Acids / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D017962:alpha-Linolenic Acid / Q000008:administration & dosage
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D010455:Peptides; D014409:Tumor Necrosis Factor-alpha; C052929:collagen type I trimeric cross-linked peptide; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid; D000469:Alkaline Phosphatase