|Keywords:||Dietetics and Human Nutrition|
|Full text PDF:||http://digitool.library.mcgill.ca/thesisfile141608.pdf|
The attainment of an adequate peak bone mass is vital to prevent against the development of osteoporosis later in life. As such, factors that influence the development of bone mass during growth should be investigated in support of attaining the highest peak bone mass possible. Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) and omega-6 (n-6) LCPUFA have been associated with decreased rates of bone resorption in older adults, however their associations with bone modeling in children remain unclear. Therefore, the objective of the study was to investigate relationships between red blood cell (RBC) n-6 and n-3 LCPUFA and bone mineral density (BMD) at the whole body (WB) and lumbar spine (LS), in young children.For this cross-sectional analysis, participants 2 through 8 years of age had socio-demographic information, anthropometry, and dietary intake assessments performed using standard protocols. BMD was assessed at the WB and LS using dual-energy X-ray absorptiometry and values were converted to z-scores to account for age and sex. RBCs were separated from a fasted blood sample in order to assess LCPUFA status. Participants were classified into tertiles based upon the proportion of each respective LCPUFA to total RBC fatty acids. A mixed model ANOVA tested for differences among the tertiles in relation to BMD with covariates including ethnicity, serum 25-hydroxyvitamin D concentration, family income, parental education, and physical activity, with Bonferroni adjustment as the post-hoc analysis.The participants (n = 49, 5.64 ± 1.93 y), were 59% male, 65% white, had a height z-score of 0.35 ± 0.97 and had a BMI z-score of 0.65 ± 0.84. Participants in the highest tertiles of eicosapentaenoic acid (EPA) and ∑ n-3 had significantly higher LS BMD z-scores compared to participants in the lowest and middle tertiles. In contrast, participants in the highest tertile for the ratio of n-6:n-3 LCPUFA, had significantly lower LS BMD z-scores compared to participants in the lowest tertile. No differences among tertiles were observed for any RBC n-3 LCPUFA and WB BMD z-scores, however, participants in the highest tertiles of ∑ n-6 and ∑ LCPUFA had significantly higher WB BMD z-scores than those in both the lowest and middle tertiles.These results suggest that both n-3 LCPUFA and n-6 LCPUFA are beneficial for bone modeling during childhood and as such, increasing dietary intakes of LCPUFA-rich foods should be addressed in an effort to positively influence bone mass during this life-stage. Les acides gras polyinsaturés à longues chaines (AGPI-LC) communément appelés omega-3 (n-3) et les oméga-6 (n-6), ont été associés à une diminution du taux de résorption osseuse chez les personnes âgées ; mais leurs associations avec la modélisation des os chez les enfants restent ambiguës. Par conséquent, l'objectif de l'étude était d'étudier les relations entre les globules rouges (GR) n-6 et n-3 et la densité minérale osseuse (DMO) pour le corps entier (CE) et le rachis lombaire (RL) chez les jeunes enfants. Pour cette analyse… Advisors/Committee Members: Hope Weiler (Internal/Supervisor).