A study on absorption and utilization of calcium, iron and zinc in mineral-fortified and dephytinized soy milk powder consumed by boys aged 12 to 14 years / 中华预防医学杂志

<p><b>OBJECTIVES</b>In order to understand the absorption and utilization of calcium, iron and zinc in cow milk, soy milk powder and dephytinized soy milk powder in the children and adolescents, and to lay a foundation for the improvement of protein and mineral nutrition in Chinese residents with popularizing consumption of soy milk powder.</p><p><b>METHODS</b>Totally, 57 boys aged 12 to 14 years were selected and divided into three groups, matched by age, hemoglobin concentration, height and weight. The boys were given 220 ml of fortified and dephytinized soy milk, soy milk or cow milk, respectively, containing calcium 270 mg, iron 4 mg and zinc 4 mg, which were labeled with stable isotopes (44)Ca, (58)Fe and (70)Zn in a single serving size, and their feces were labeled with brilliant blue and dysprosium. Feces specimens were collected for all the subjects and absorption rate of calcium, iron and zinc were measured for all the children who took fortified and dephytinized soy milk, soy milk or cow milk, respectively. Calcium in feces was measured with heat ionized mass spectrometry, and recovery of (58)Fe and (70)Zn in feces and content of dysprosium were measured with induction coupling iso-ionic mass spectrometry, and then absorption rates of iron and zinc were calculated and adjusted by the recovery rate of dysprosium.</p><p><b>RESULTS</b>Iron absorption rate was (6.7 +/- 3.8)% in soy milk powder group, (15.5 +/- 9.2)% in the cow milk group and (20.6 +/- 7.3)% in dephytinized soy milk powder group, respectively. Calcium absorption rate was (43.5 +/- 10.7)%, (64.2 +/- 11.4)%, and (50.9 +/- 6.6)% in the three groups, respectively. Absorption rate of zinc was (11.3 +/- 6.5)%, (31.2 +/- 10.4)% and (20.1 +/- 7.4)%, respectively. Significant increase in absorption of calcium, iron and zinc was observed in the groups with fortified and dephytinized soy milk powder, as compared with those consuming nondephytinized soy milk powder. Absorption rate of calcium and zinc was significantly higher in the group with cow milk than that in the group with dephytinized and fortified soy milk powder, and iron bioavailability was lower in the group with cow milk than that with dephytinized soy milk powder, with no significant difference. Absorption rates of calcium, iron and zinc were higher in children of China due to their long term adaptation to dietary intake of lower mineral and protein, and higher fiber.</p><p><b>CONCLUSIONS</b>Bioavailability of calcium, iron and zinc in soy milk powder could be increased by dephytinized treatment for it.</p>

Effect of long term supplementation of mineral-fortified dephytinized soy milk powder on biomarkers of bone turnover in boys aged 12 to 14 years / 中华预防医学杂志

<p><b>OBJECTIVES</b>In order to understand the effect of long term consumption of mineral-fortified dephytinized soy milk powder on skeletal health in children, biological effects of mineral-fortified dephytinized soy milk powder, dephytinized mineral-unfortified soy milk powder and fresh mineral-fortified cow milk were compared.</p><p><b>METHODS</b>Totally, 90 boys aged 12 to 14 years were involved in the study and were given daily with mineral-fortified dephytinized soy milk powder, dephytinized soy milk powder and fresh fortified cow milk, respectively, for two months. The blood samples were collected from all the subjects for measuring activity of serum bone specific alkaline phosphatase and serum level of oesteocalcin, and the urine samples were collected for determining urine C-terminal telopeptides of type I collagen (CTx).</p><p><b>RESULTS</b>After two-month intervention, serum level of oesteocalcin increased significantly in the all groups, (16.42 +/- 11.25) micro g/L for the group with fortified soy milk powder, (18.86 +/- 11.57) microg/L for the group with unfortified soy milk powder and (13.81 +/- 10.06) microg/L for the group with fortified cow milk, respectively. The activity of bone specific alkaline phosphatase significantly decreased in the all groups, by (0.28 +/- 0.40) micromol x s(-1) x L(-1) for the group with fortified soy milk powder, (0.26 +/- 0.35) micromol x s(-1) x L(-1) for the group with unfortified soy milk powder, and (0.17 +/- 0.28) micromol x s(-1) x L(-1) for the group with fortified cow milk, respectively. As well as, urine level of CTx decreased significantly, by (349.1 +/- 380.3) mg/L for the group with fortified soy milk powder, (260.4 +/- 412.4) mg/L for the group with unfortified soy milk powder, and (354.4 +/- 404.7) mg/L for the group with fortified cow milk, respectively.</p><p><b>CONCLUSIONS</b>Long term consumption of mineral-fortified and dephytinized soy milk powder could improve bone mass retention and calcium nutrition status efficiently in children.</p>