title: The effects of a low-sodium base-producing diet including red meat compared with a high-carbohydrate, low-fat diet on bone turnover markers in women aged 45-75 years.
abstract: A randomised, parallel-design dietary intervention study was conducted in women (aged 45-75 years) with prehypertension or stage 1 hypertension. The aim was to compare the effects on bone turnover of a low-Na base-producing (LNAB) Dietary Approaches to Stop Hypertension (DASH)-type diet (including six serves lean red meat/week) with a high-carbohydrate low-fat (HCLF) diet with a higher acid load (both >800 mg dietary Ca/d). Fasting serum bone markers (baseline and week 14) and 24 h urinary electrolyte excretion (baseline, weeks 4, 8, 12 and 14) were measured. After the intervention period, the LNAB group (n 46) had a fall of 26 (sem 6) % (P < 0.0001) in urinary Na, an increase in K excretion (6.8 (sem 3.6) mmol/d; P = 0.07) and, compared with the HCLF group (n 49), a greater reduction in urinary Ca excretion by 0.7 (sem 0.3) mmol/d. Serum 25-hydroxyvitamin D, intact parathyroid hormone and osteocalcin did not change, and both groups had a similar increase of 23 (sem 5) % (P < 0.0001) in C-terminal telopeptide of type I collagen. The HCLF group had an 11 (sem 4) % increase (P = 0.003) in N-terminal propeptide, type I procollagen, which could indicate an increased rate of bone turnover. The fall in urinary Ca with the lower-Na lower-acid load diet is likely to have long-term beneficial effects on bone. As bone resorption was not different between the two dietary patterns with relatively high Ca intake, the effect on bone health of a dietary pattern with a lower acid load warrants further study on a lower Ca intake.
authors.affiliation: School of Exercise and Nutrition Sciences, Centre for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood 3125, Victoria, Australia. caryl.nowson@deakin.edu.au
authors.forename: Caryl A
authors.initials: CA
authors.lastname: Nowson
authors.forename: Annabelle
authors.initials: A
authors.lastname: Patchett
authors.forename: Naiyana
authors.initials: N
authors.lastname: Wattanapenpaiboon
mesh_terms: D000136:Acid-Base Equilibrium; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D016723:Bone Remodeling / Q000187:drug effects* / Q000502:physiology; D001862:Bone Resorption / Q000503:physiopathology; D002118:Calcium / Q000652:urine; D004032:Diet; D018752:Diet, Fat-Restricted; D004039:Diet, Sodium-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D008460:Meat; D008875:Middle Aged; D011188:Potassium / Q000652:urine; D012964:Sodium / Q000652:urine
chemical_list: D015415:Biomarkers; D004040:Dietary Carbohydrates; D012964:Sodium; D011188:Potassium; D002118:Calcium