AUTHOR=Gu Hongru , Gong Yijing , Li Zhao , Zhang Yanqiu , Wu Jin , Wang Yi , Ni Min , Zhang Jun , Jiang Hai 

TITLE=Contribution of direct-drinking water to calcium and magnesium and the influence on the height in school-age children

JOURNAL=Frontiers in Nutrition

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1434952

DOI=10.3389/fnut.2024.1434952

ISSN=2296-861X

ABSTRACT=<sec id="sec1"><title>Objective</title><p>To estimate the contribution of direct-drinking water provided in school to dietary intake (DI) and recommended nutrient intake (RNI) of calcium and magnesium, and to explore its influence on the height in school-age children.</p></sec><sec id="sec2"><title>Methods</title><p>Tap water and direct-drinking water samples were collected from schools in Taicang City to test the contents of calcium and magnesium, and compared by one-way ANOVA and <italic>post-hoc</italic> test. Contribution rates of direct-drinking water to DI and RNI were calculated by using the contents of calcium and magnesium and data from the <italic>Nutrition and Health Status Survey 2021</italic>. A retrospective cohort was conducted among 4,850 first-grade children consuming direct-drinking water in Taicang City from 24 primary schools in 2019. Group 1 (1,070 boys and 946 girls) consumed UF-process water with normal calcium and magnesium contents and Group 2 (1,548 boys and 1,286 girls) consumed NF/RO-process water with very low calcium and magnesium contents. During 2019–2023, the height and height growth were analyzed with the Student’s <italic>t</italic>-test.</p></sec><sec id="sec3"><title>Results</title><p>The highest calcium content was examined in tap water samples, followed by direct-drinking water samples supplied through a UF, NF, and RO system (<italic>F</italic> = 1,227.725, <italic>p</italic> &lt; 0.001). The highest magnesium content was examined in water supplied through a UF system, followed by that through a tap, NF and RO system (<italic>F</italic> = 146.504, <italic>p</italic> &lt; 0.001). Calcium and magnesium contents in direct-drinking water supplied through a UF system changed little compared with those in tap water, which were significantly reduced in direct-drinking water supplied through a NF and RO system. The contribution rates of direct-drinking water to DI of calcium and magnesium were 8.95 and 2.78%, respectively, and those to RNI of calcium and magnesium were 2.63 and 1.96%, respectively. There were no significant differences in the height and height growth of first-grade children drinking water supplied through the UF system vs. NF/RO system (<italic>p</italic> &gt; 0.05).</p></sec><sec id="sec4"><title>Conclusion</title><p>Direct-drinking water processed through a NF or RO system should be cautiously adopted in primary and secondary schools. A UF system is preferred in schools where no health concerns are associated with water quality.</p></sec>