title: Effect of potassium citrate supplementation or increased fruit and vegetable intake on bone metabolism in healthy postmenopausal women: a randomized controlled trial.
abstract: BACKGROUND
  Alkali provision may explain why fruit and vegetables benefit bone health.
  
  
  OBJECTIVE
  We aimed to determine the effects of alkali-providing potassium citrate (double-blind) and fruit and vegetable intake (single-blind) on bone turnover over 2 y.
  
  
  METHODS
  We conducted a randomized placebo-controlled trial in 276 postmenopausal women (aged 55-65 y). Women were randomly assigned to 4 groups: high-dose potassium citrate (55.5 mEq/d), low-dose potassium citrate (18.5 mEq/d), placebo, and 300 g additional fruit and vegetables/d (equivalent of 18.5 mEq alkali). Serum and fasted urine for bone markers were collected at baseline and at 3, 6, 12, 18, and 24 mo. An additional urine sample was collected at 4-6 wk. Bone mineral density (BMD) was measured at baseline and 2 y.
  
  
  RESULTS
  Repeated-measures ANOVA showed no difference between groups for urinary free deoxypyridinoline cross-links relative to creatinine (fDPD/Cr), serum N-terminal propeptide of type 1 collagen, or beta C-terminal telopeptide, although, at 4-6 wk, fDPD/Cr was lower in the high-dose potassium citrate group (P = 0.04). Mean +/- SD spine BMD loss in the placebo group (1.8 +/- 3.9%) did not differ significantly from that in the treatment groups (2.1 +/- 3.2%; P = 0.88). Hip BMD loss in the placebo and low-dose potassium citrate groups was 1.3 +/- 2.3% and 2.2 +/- 2.3%, respectively (P = 0.14).
  
  
  CONCLUSIONS
  Two-year potassium citrate supplementation does not reduce bone turnover or increase BMD in healthy postmenopausal women, which suggests that alkali provision does not explain any long-term benefit of fruit and vegetable intake on bone.
authors.affiliation: University of Aberdeen, Aberdeen, United Kingdom. h.macdonald@abdn.ac.uk
authors.forename: Helen M
authors.initials: HM
authors.lastname: Macdonald
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Black
authors.forename: Lorna
authors.initials: L
authors.lastname: Aucott
authors.forename: Garry
authors.initials: G
authors.lastname: Duthie
authors.forename: Susan
authors.initials: S
authors.lastname: Duthie
authors.forename: Rena
authors.initials: R
authors.lastname: Sandison
authors.forename: Antonia C
authors.initials: AC
authors.lastname: Hardcastle
authors.forename: Susan A
authors.initials: SA
authors.lastname: Lanham New
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
authors.forename: David M
authors.initials: DM
authors.lastname: Reid
mesh_terms: D000368:Aged; D000596:Amino Acids / Q000652:urine; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density / Q000187:drug effects*; D001862:Bone Resorption / Q000517:prevention & control; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D024042:Collagen Type I / Q000097:blood; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005638:Fruit; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000209:etiology / Q000517:prevention & control; D010455:Peptides / Q000097:blood; D017698:Postmenopause; D019357:Potassium Citrate / Q000008:administration & dosage*; D016037:Single-Blind Method; D014675:Vegetables
chemical_list: D000596:Amino Acids; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; C036020:deoxypyridinoline; D019357:Potassium Citrate