Dietary acid-base balance, bone resorption, and calcium excretion.
OBJECTIVE
Metabolic studies reveal that acidogenic diets increase bone resorption acutely. This study was conducted to examine associations between diet-induced changes in net acid excretion (NAE) and changes in serum parathyroid hormone (PTH), bone resorption, and calcium excretion over a longer period of 60 days.


METHODS
Forty healthy older men and women were given 0.75 g/kg of protein as meat, 600 mg of calcium, and 400 IU of vitamin D3 daily and either cereal (acidogenic) or fruit and vegetable (alkalinogenic) foods as substitutes for some of the cereal in their usual diets. Blood and 24-hr urine measurements were made on days 14 (baseline), 44, and 74.


RESULTS
In all subjects, change in renal NAE was correlated with changes in serum PTH (r = 0.358, P = 0.023), urinary N-telopeptide (NTX) (r = 0.367, P = 0.020), and urinary calcium excretion (rp = 0.381, P = 0.020, after adjustment for diet group, change in PTH, and change in sodium excretion).


CONCLUSIONS
Diet changes that increase renal NAE are associated with increases in serum PTH, bone resorption, and calcium excretion over a 60-day period.
Jajoo
Ramina
R
Division of Rheumatology, Tufts-New England Medical Center, Bone Metabolism Laboratory at the Jean Mayer, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
Song
Lingyi
L
Rasmussen
Helen
H
Harris
Susan S
SS
Dawson-Hughes
Bess
B
D000136:Acid-Base Equilibrium / Q000502:physiology*; D015415:Biomarkers / Q000652:urine; D001862:Bone Resorption / Q000378:metabolism* / Q000652:urine; D002118:Calcium / Q000652:urine*; D002762:Cholecalciferol / Q000008:administration & dosage / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D017419:Potassium, Dietary / Q000008:administration & dosage / Q000378:metabolism; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000378:metabolism
D015415:Biomarkers; D004044:Dietary Proteins; D010281:Parathyroid Hormone; D017419:Potassium, Dietary; D012982:Sodium, Dietary; D002762:Cholecalciferol; D002118:Calcium