Dietary calcium intakes and major contributing food sources of adolescent males in New Zealand

Abstract

Background: Calcium plays an important role in optimising bone health. Sufficient intakes are especially important during periods of growth and development, to ensure the attainment of peak bone mass- a strong predictor of later life fracture and osteoporosis risk. Adolescents have among the highest dietary calcium requirements of any lifecycle group, with an estimated average requirement of 1050 mg/day. The high calcium requirements necessary for this lifecycle group creates challenges in achieving a sufficient intake, especially when coupled with the changes in dietary patterns associated with this life period. Usual daily calcium intakes and the prevalence of inadequacy among New Zealand male adolescents is currently unknown, with the last available data captured over a decade ago. Moreover, the wider implications of changes in food consumption and supply over this period, in particular, the downward trend in consumption of milk and dairy products, could have an influence on the dietary calcium intakes of adolescents. Objective: To determine usual dietary calcium intakes, major contributing food sources of calcium, and examine specific dietary habits known to influence calcium intakes of New Zealand male adolescents aged 15-18 years. Design: The present study used data from a cross-sectional, multi- site survey of 135 adolescent males (15-18 years), recruited across 6 New Zealand high schools between February and March 2020. Socio-demographic and dietary habit data were collected using online questionnaires and weight and height were taken for calculation of body mass index. Dietary intake data was obtained via two 24-hr diet recalls, with the multiple source method (MSM) used to adjust for usual calcium intake. The estimated average requirement (EAR) cut-point method was applied to estimate the prevalence of inadequate calcium intake. Results: The usual median (IQR) of calcium intakes of the sample population were low, 935 (656, 1222) mg/day . The prevalence of inadequacy was high (63%), with Asians, and those residing in low deprivation neighbourhoods identified as being at increased risk of calcium inadequacy (76% and 71%, respectively). Energy intakes appeared positively related to calcium intakes, as evident by concurrently high energy and calcium intakes among various subgroups. Milk was widely consumed among participants (77%) and as such, was the most valuable source of calcium, contributing nearly one-third (28%) to total calcium intakes of the sample population. Additional calcium contributing food groups included cheese (11%), bread (8%), bread-based dishes (6%) and non-alcoholic beverages (6%). The highest dietary calcium intakes were demonstrated among participants who reported frequently consuming milk and dairy products (several times per week, daily, or multiple times per day) and breakfast (everyday), and avoided sugar-sweetened beverages (non-consumers or rarely consumed). Conclusion: The reported intakes of calcium were suboptimal in our sample of adolescent males, resulting in a high percentage of the population not meeting current recommended intakes. Improved calcium intakes were reported among frequent consumers of milk, dairy and breakfast, and those who avoided sugar-sweetened beverages. Given the consequences associated with failure to achieve sufficient calcium intakes during this period, a nationally representative investigation of the calcium intakes of NZ adolescent males is required, allowing for discernment of whether there is need for further interventions to address this nutritional concern.