Effect of milk and milk products consumption on physical growth and bone mineral density in Korean adolescents

This study was conducted to investigate the relationship among the current status of calcium intake from milk and milk products, physical growth and bone mineral density in 664 male and female middle school and high school students aged 15-17 years. In the study, the current status of calcium intake from milk and milk products was analyzed, and the height, body composition, and bone mineral density of the right heel bone (calcaneus) were measured. The daily calcium intake of milk and milk products was calculated as the 'dairy equivalent of calcium', which is the calcium content in 200 mL of white milk. The cutoffs of tertiles of the dairy equivalent of calcium were calculated and then the subjects were categorized into 3 groups according to the tertiles, Q1 group (lower intake group), Q2 group (middle intake group) and Q3 group (upper intake group). The daily calcium intake of milk and milk products in Q1, Q2 and Q3 groups was 16.2 mg, 99.7 mg, and 284.0 mg, respectively, and the ratio of milk and milk product consumption to the daily total calcium intake was 5.4%, 27.4%, and 49.7%, respectively. The ratio of total calcium intake to the daily recommended intake in study subjects was 30.5% in Q1, 42.3% in Q2, and 60.7% in Q3, with significant differences (P < 0.05). Height, body weight, BMI, and % of body fat in three tertile groups (Q1, Q2 and Q3) were not significantly different. However, the T scores for bone mineral density in female students in three tertile groups (Q1, Q2 and Q3) was significantly different (P < 0.05). The study showed that the intake of milk and milk products in adolescents, particularly in girls, can improve the bone mineral density without increasing body weight, and thus confirmed that milk intake is important in adolescence.

Preference and Consumption Pattern of Middle and High School Students on Milk and Milk Products, in Geochang Area

This study was performed to investigate the preference and consumption pattern on milk and milk products of middle and high school students. The subjects were 1,195 students(590 middle school and 605 high school students) living in Geochang area. The survey was conducted by using a self-administered questionnaire in November, 2004. The results were as follows. Sixty-three point four percent of the subjects liked milk, and the main reason was 'accelerate growth and development'(55.4%). Preferred tastes of milk were 'savory taste'(35.4%) and 'sweet taste' (29.9%). Banana milk, chocolate milk, strawberry milk, ice cream, yoplait and yogurt were highly preferred. General preference for different kinds of milk was significantly higher in high school students and male students than in middle school students and female ones. With regard to preference for dairy products, cream (p<0.01) and butter(p<0.05) was preferred more by male students than by female ones, ice cream(p<0.05), yoplait (p<0.05) more by female students than male ones. The score of milk intake frequency was 3.84(3~4 times a week) out of 5 points(7 times a week) for white milk, and that of chocolate milk was 1.98, banana milk 1.96, strawberry milk 1.72, coffee milk 1.65, showing that these products were drank less then once a week. In addition, the white milk intake frequency was significantly higher in middle school students and male students than in high school students and female students(p<0.001). Preference for milk showed a positive correlation with preference for dairy products (r=0.543, P<0.001) and frequency of milk intake(r=0.429, P<0.001). This suggests that those who prefer milk high tend to prefer dairy products and to show high milk intake frequency. In addition, milk intake frequency was in a high positive correlation with dairy product intake frequency(r=0.648, P<0.001).