Background: Calcium requirements during adolescence are high due to rapid skeletal growth throughout this key life stage. Increased peak bone mass has been found to decrease risk of osteoporosis in later life. Peak bone mass achieved during adolescence is determined by the degree of positive calcium balance achieved in this period. Given the current burden of osteoporosis in the aged population of New Zealand, investigation of dietary calcium intake in adolescents could help contribute to optimal bone health as these adolescents move into adulthood.
Objective: To assess the current dietary calcium intake of New Zealand male and female adolescents aged 15-18 years. Key food sources of dietary calcium will also be examined.
Design: This cross-sectional cluster study carried out across 2019/20 collected data on demographics, dietary habits, food choices and motivations, weight loss methods and intentions using online questionnaires. The participant’s food and beverage intakes were assessed using two non-consecutive 24 hr dietary recalls. Dietary data was entered into the nutrient analysis software Foodworks, which calculated mean daily energy and calcium intake data for each participant. Prevalence of inadequate calcium intake was assessed using the Estimated Average Requirement (EAR) cut-point method.
Results: A total of 266 females and 135 males participated in the study with calcium intake calculated for 243 females and 102 males. The majority of participants identified as New Zealand European or other (57% of males, 78% of females), with 32% of males identifying as Asian, compared to 3.4% of females. Mean (standard deviation) energy intakes were 10,077 kJ/day (3215) for males and 7959 kJ/day (1781) for females. Median (inter-quartile range) calcium intakes were 935 mg/day (656, 1222) for males and 711 mg/day (551,915) for females. Prevalence of inadequate calcium intake (based on EAR of 1050 mg/day) was 63% for males and 85% for females. Milk was the top food source contributor to calcium intake, providing 17% and 28% of average daily calcium for males and females respectively.
Conclusion: Findings from this study reflect a high prevalence of inadequate calcium intakes in the New Zealand adolescent population, particularly in females. The results indicate there is likely a large proportion of adolescents who are at high risk of osteoporosis in later life. Dietitians should continuously consider practical ways to assist this population group in meeting such calcium high requirements. Further investigation into the calcium intake and correlating bone health specifically of this population within New Zealand may be required
