The primary purpose of this study was to estimate the magnitude and variability of peak calcium accretion rates in the skeletons of healthy white adolescents. Total‐body bone mineral content (BMC) ...was measured annually on six occasions by dual‐energy X‐ray absorptiometry (DXA; Hologic 2000, array mode), a BMC velocity curve was generated for each child by a cubic spline fit, and peak accretion rates were determined. Anthropometric measures were collected every 6 months and a 24‐h dietary recall was recorded two to three times per year. Of the 113 boys and 115 girls initially enrolled in the study, 60 boys and 53 girls who had peak height velocity (PHV) and peak BMC velocity values were used in this longitudinal analysis. When the individual BMC velocity curves were aligned on the age of peak bone mineral velocity, the resulting mean peak bone mineral accrual rate was 407 g/year for boys (SD, 92 g/year; range, 226–651 g/year) and 322 g/year for girls (SD, 66 g/year; range, 194–520 g/year). Using 32.2% as the fraction of calcium in bone mineral, as determined by neutron activation analysis (Ellis et al., J Bone Miner Res 1996;11:843‐848), these corresponded to peak calcium accretion rates of 359 mg/day for boys (81 mg/day; 199–574 mg/day) and 284 mg/day for girls (58 mg/day; 171–459 mg/day). These longitudinal results are 27–34% higher than our previous cross‐sectional analysis in which we reported mean values of 282 mg/day for boys and 212 mg/day for girls (Martin et al., Am J Clin Nutr 1997;66:611‐615). Mean age of peak calcium accretion was 14.0 years for the boys (1.0 years; 12.0‐15.9 years), and 12.5 years for the girls (0.9 years; 10.5‐14.6 years). Dietary calcium intake, determined as the mean of all assessments up to the age of peak accretion was 1140 mg/day (SD, 392 mg/day) for boys and 1113 mg/day (SD, 378 mg/day) for girls. We estimate that 26% of adult calcium is laid down during the 2 adolescent years of peak skeletal growth. This period of rapid growth requires high accretion rates of calcium, achieved in part by increased retention efficiency of dietary calcium.
BACKGROUND: Nutrition is an important modifiable factor in the development of bone mass during adolescence. Recent studies of children and adolescents examined the effects of foods such as milk ...products and fruit and vegetables on bone growth; however, few studies included both boys and girls. OBJECTIVE: The purpose was to ascertain the role of consumption of milk products and vegetables and fruit in the accrual of total-body bone mineral content (TBBMC) in boys and girls from childhood to late adolescence. DESIGN: Seven-year longitudinal data were obtained from 85 boys and 67 girls aged 8-20 y. Biological maturity was defined by the number of years from the age at peak height velocity. Dietary intake was assessed by serial 24-h recalls. Anthropometric measurements and physical activity were assessed every 6 mo. TBBMC assessed with dual-energy X-ray absorptiometry in the fall of each year was the indicator of bone mass. RESULTS: Most boys (87.8%) met Canadian recommendations for milk product intake. Few subjects (<30%) consumed vegetables and fruit in recommended amounts. Using a multilevel modeling statistical approach containing important biological and environmental factors, we found that vegetable and fruit intakes, calcium intake, and physical activity were significant independent environmental predictors of TBBMC in boys but not in girls. CONCLUSIONS: In addition to adequate dietary calcium intake, appropriate intakes of vegetables and fruit have a beneficial effect on TBBMC in boys aged 8-20 y. Underreporting of dietary intake by girls may explain why this effect was not apparent in girls.
The development of bone mass during the growing years is an important determinant for risk of osteoporosis in later life. Adequate dietary intake during the growth period may be critical in reaching ...bone growth potential. The Saskatchewan Bone Mineral Accrual Study (BMAS) is a longitudinal study of bone growth in Caucasian children. We have calculated the times of maximal peak bone mineral content (BMC) velocity to be 14.0 ± 1.0 y in boys and 12.5 ± 0.9 y in girls; bone growth is maximal ∼6 mo after peak height velocity. In the 2 y of peak skeletal growth, adolescents accumulate over 25% of adult bone. BMAS data may provide biological data on calcium requirements through application of calcium accrual values to factorial calculations of requirement. As well, our data are beginning to reveal how dietary patterns may influence attainment of bone mass during the adolescent growth spurt. Replacing milk intake by soft drinks appears to be detrimental to bone gain by girls, but not boys. Fruit and vegetable intake, providing alkalinity to bones and/or acting as a marker of a healthy diet, appears to influence BMC in adolescent girls, but not boys. The reason why these dietary factors appear to be more influential in girls than in boys may be that BMAS girls are consuming less than their requirement for calcium, while boys are above their threshold. Specific dietary and nutrient recommendations for adolescents are needed in order to ensure optimal bone growth and consolidation during this important life stage.
Adequate dietary intake during the growth period is critical for bone mineral accretion. In 1997, an adequate intake (AI) of 1300 mg/d Ca was set for North American adolescents aged 9–18 years based ...on best available data. We determined bone Ca accrual values from age 9 to 18 years taking into account sex and maturity. Furthermore, we used the accrual data to estimate adolescents' Ca requirements. Total body bone mineral content (TBBMC) of eighty-five boys and sixty-seven girls participating in the Saskatchewan Paediatric Bone Mineral Accrual Study were used to determine annual TBBMC accumulation over the pubertal growth period. Using a similar factorial approach as the AI, we estimated Ca requirements of adolescent boys and girls for two age groups: 9–13 and 14–18 years. Between 9 and 18 years, boys accrued 198·8 (sd 74·5) g bone mineral content (BMC) per year, equivalent to 175·4 (sd 65·7) mg Ca per d with the maximum BMC accrual of 335·9 g from age 13 to 14 years. Girls had 138·1 (sd 64·2) g BMC per year, equalling121·8 (sd 56·6) mg Ca per d with the maximum annual BMC accrual of 266·0 g from age 12 to 13 years. Differences were observed between both sex and age groups with respect to Ca needs: boys and girls aged 9–13 years would require 1000–1100 mg/d Ca, and from age 14 to 18 years, the mean Ca requirements would be relatively stable at 1000 mg/d for girls but would rise to 1200 mg/d for boys.
To determine whether a significant relationship exists between fat mass (FM) development and physical activity (PA) and/or sugar-sweetened drink (SD) consumption in healthy boys and girls aged 8-19 ...yr.
A total of 105 males and 103 females were assessed during childhood and adolescence for a maximum of 7 yr and a median of 5 yr. Height was measured biannually. Fat-free mass (FFM) and FM were assessed annually by dual x-ray absorptiometry (DXA). PA was evaluated two to three times annually using the PAQ-C/A. Energy intake and SD were assessed using a 24-h dietary intake questionnaire also completed two to three times per year. Years from peak height velocity were used as a biological maturity age indicator. Multilevel random effects models were used to test the relationship.
When controlling for maturation, FFM, and energy intake adjusted for SD, PA level was negatively related to FM development in males (P<0.05) but not in females (P>0.05). In contrast, there was no relationship between SD and FM development of males or females (P>0.05). There was also no interaction effect between SD and PA (P>0.05) with FM development.
This finding lends support to the idea that increasing PA in male youths aids in the control of FM development. Models employed showed no relationship between SD and FM in either gender.
The effect of dietary protein on bone mass measures at different life stages is controversial. We investigated the influence of protein intake on bone mass measures in young adults, considering the ...influence of calcium intake through adolescence. Subjects were 133 young adults (59 males, 74 females) who were participating in the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-1997, 2003-2006). At adulthood, their mean age was 23 y. We assessed dietary intake via serial 24-h recalls carried out at least once yearly. Total body (TB) bone mineral content (BMC) and TB bone mineral density (BMD) were assessed annually using Dual energy X-ray absorptiometry. We determined TB-BMC net gain from the age of peak height velocity (PHV) to early adulthood. We analyzed data from all subjects and subsets based on sex and calcium intake using multiple regression. TB-BMC significantly increased from age at PHV to early adulthood by 41% in males and 37% in females. Height, weight, physical activity, and sex were significant predictors of TB-BMC, TB-BMC net gain, and TB-BMD among all subjects. Protein intake predicted TB-BMC net gain in all subjects (β = 0.11; P = 0.015). In females at peri-adolescence or early adulthood with adequate calcium intake (>1000 mg/d), protein intake positively predicted TB-BMC, TB-BMC net gain, and TB-BMD (P < 0.05). Our results indicate that when calcium intake is adequate, protein intake has a beneficial effect on the bone mass of young adult females. Protein, in the absence of sufficient calcium, does not confer as much benefit to bone.
Low nutrient dense beverages such as carbonated drinks are increasing in the adolescent’s diet, and concern has been raised that these beverages, particularly colas, reduce bone mass. We determined ...whether the type of low nutrient dense beverage as well as the amount was related to bone mineral content and accumulation during the two years spanning the time of peak bone mass accrual in adolescence. Total body bone mineral content (BMC) and dietary intakes were obtained for 59 boys and 53 girls when each subject was ± one year of his or her measured age of peak rate of BMC. Consumption of low nutrient dense beverages was negatively related to BMC (r = −0.256, P = 0.03) and accrual (r = −0.227, P = 0.05) for adolescent girls but not boys. Milk beverage intake in both boys and girls was inversely related to low nutrient dense beverage consumption (r = −0.343, P = 0.01; r = −0.244, P = 0.08, respectively). Low nutrient dense beverage ingestion by adolescents appeared to reduce bone mineral accrual and BMC in teenage girls by replacing milk beverages.
We measured bone mineral content (BMC) and estimated calcium accretion in children to provide insight into dietary calcium requirements during growth. Anthropometric measurements were done ...semiannually and whole-body BMC was measured annually by dual-energy X-ray absorptiometry for 4 y in 228 children (471 scans in 113 boys and 507 scans in 115 girls). Mean values for BMC, skeletal area, and height were calculated for 1-y age groups from 9.5 to 19.5 y of age. Cross-sectional analysis of the pooled data gave peak height velocity and peak BMC velocity (PBMCV) and the ages at which these occurred (13.3 y in boys and 11.4 y in girls). PBMCV did not peak until 1.2 y after peak height velocity in boys and 1.6 y after peak height velocity in girls. Within 3 y on either side of PBMCV, boys had consistently higher BMC and BMC velocity compared with girls and the discrepancy increased steadily through puberty. Three years before PBMCV, BMC values in girls were 69% of those in boys; 3 y after peak height velocity this proportion fell to 51%. PBMCV was 320 g/y in boys and 240 g/y in girls. Under the assumption that bone mineral is 32.2% calcium, these values corresponded to a daily calcium retention of 282 mg in boys and 212 mg in girls. Individual values could be much greater. In one boy in a group of six subjects for whom there were enough data for individual analysis through puberty, PBMCV was 555 g Ca/y or 490 mg Ca/d. Such high skeletal demands for calcium require large dietary calcium intakes and such requirements may not be met immediately in some children.
The effect of dietary protein on bone mass measures at different life stages is controversial. We investigated the influence of protein intake on bone mass measures in young adults, considering the ...influence of calcium intake through adolescence. Subjects were 133 young adults (59 males, 74 females) who were participating in the Saskatchewan Pediatric Bone Mineral Accrual Study (1991–1997, 2003–2006). At adulthood, their mean age was 23 y. We assessed dietary intake via serial 24-h recalls carried out at least once yearly. Total body (TB) bone mineral content (BMC) and TB bone mineral density (BMD) were assessed annually using Dual energy X-ray absorptiometry. We determined TB-BMC net gain from the age of peak height velocity (PHV) to early adulthood. We analyzed data from all subjects and subsets based on sex and calcium intake using multiple regression. TB-BMC significantly increased from age at PHV to early adulthood by 41% in males and 37% in females. Height, weight, physical activity, and sex were significant predictors of TB-BMC, TB-BMC net gain, and TB-BMD among all subjects. Protein intake predicted TB-BMC net gain in all subjects (β = 0.11; P = 0.015). In females at peri-adolescence or early adulthood with adequate calcium intake (>1000 mg/d), protein intake positively predicted TB-BMC, TB-BMC net gain, and TB-BMD (P < 0.05). Our results indicate that when calcium intake is adequate, protein intake has a beneficial effect on the bone mass of young adult females. Protein, in the absence of sufficient calcium, does not confer as much benefit to bone.
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