title: [The effects of dietary calcium and protein intake on changes in bone mineral density during early and late stages of pregnancy].
abstract: OBJECTIVE
  The study was performed to examine the effects of calcium (Ca) and protein intake on changes in bone mineral density during early and late stages of pregnancy, including the relationship to bone metabolism.
  
  
  METHODS
  In 40 pregnant women, bone mineral density (BMD) was measured three times: at 11-16 weeks of gestation, at 24-28 weeks and within one week postpartum using ultrasonic bone densitometry. Bone metabolic markers in urine and serum were measured at the same time points. Ca and protein intakes over a three-day period were analyzed in relation to changes in BMD during the early and late stages of pregnancy, as well as to bone metabolic markers. Nutrient intake was adjusted for energy intake. Stiffness calculated from the combined value of the speed of sound transfer and broadband ultrasound attenuation was used as an index of BMD.
  
  
  RESULTS
  Ca intake was positively correlated with change in BMD, whereas protein intake was negatively correlated in early and late stages of pregnancy. The extent of bone loss adjusted for Ga intake was significantly greater in women with a higher protein intake. In the early stage, Ca intake showed a positive correlation, whereas protein intake showed a negative correlation with the serum calcium/phosphorus ratio. In the late stage, Ca intake showed a positive correlation with bone alkaline phosphatase/urinary N-terminal cross-linking telopeptides of type I collagen ratio.
  
  
  CONCLUSIONS
  These findings suggest that an increase in dietary Ga intake in both early and latestages of pregnancy may be important to maintain BMD during pregnancy. An increase in Ca intake in relation to greater protein intake may be necessary to prevent bone loss during pregnancy.
authors.affiliation: Nara University of Education, Kyoto Bunkyo College.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Junko
authors.initials: J
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D006801:Humans; D049590:Postpartum Period; D011247:Pregnancy / Q000502:physiology*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second
chemical_list: D002136:Calcium, Dietary; D004044:Dietary Proteins