Calcium intake and food sources of calcium in adolescents living in the Auckland, Waikato and Bay of Plenty regions of New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand

Abstract

Background: Adolescence is a time of rapid linear growth and acquisition of bone mass. Adequate calcium intake supports rapid bone growth during this time and is crucial to help prevent osteoporosis later in life. The most recent national nutrition data from over 15 years ago showed inadequate calcium intake in New Zealand (NZ) adolescents. A recent study conducted in Dunedin found that calcium intake in older adolescents was lower than national recommendations. Milk and cheese were found to be the primary sources of calcium in NZ adolescents’ diets. This study aims to investigate current calcium dietary intake and food sources of calcium for adolescents living in NZ. Methods: This cross-sectional study presents a secondary analysis from Te Rourou Kai o Ngā Rangatahi: Eating Patterns of Young People in NZ. Adolescents (n = 310) in Auckland, Waikato, and Bay of Plenty regions of NZ, adolescents aged 12 to 18 years participated. Participants completed a demographic questionnaire and Intake24 (an online multiple-pass method 24-hour dietary recall). Data from the recalls was used to obtain calcium intakes and dietary sources of calcium. Results: The majority of participants were female (66.7%) and identified as Māori (30.3%) or NZ European (27.7%). Calcium intakes (mean  SD) were 576  419 mg and 586  444 mg for females and males respectively (p = 0.845). The median [IQR] calcium intake for female adolescents was 482 mg [286, 780], and for male adolescents was 463 mg [286, 790] (p = 0.941). The prevalence of inadequate calcium intake (based on the calcium estimated average requirement of 1050 mg/day) in females was 88.9% (n = 184) and 84.3% (n = 87) in males (p = 0.255). Predominant food sources of calcium in adolescents were savoury mixed dishes (24.5%), non-alcoholic beverages (18.2%), and milk & milk alternatives (14.6%). Conclusion: Calcium intake among participants was below the estimated average requirement, indicating a need to promote calcium-rich foods among adolescents. Primary dietary food sources of calcium included mixed dishes and non-alcoholic beverages. Further research with two non-consecutive 24-hour recalls is required to more accurately investigate calcium intake, particularly in younger adolescents, and the context in which calcium is being consumed to better understand calcium intake in NZ adolescents.