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Objective: To determine the associations between meat, dairy and zinc intake and pubertal development in adolescents in Chengdu., Methods: A total of 1320 children and adolescents aged 9-15 years in Chengdu were recruited using a stratified cluster sampling strategy. Dietary intake was assessed by the food frequency questionnaire (FFQ) and 3-day 24-hour dietary recall. Pubertal development was evaluated through physical examinations. Consumptions of meat and dairy, and zinc intake were compared between groups with different levels of pubertal development according to the Tanner criteria., Results: The median age of spermarche was 13. 00 years. The boys who had had spermarche consumed more meat (including red meat) and dairy products than those who had not yet (P<0. 05). Daily consumption of total meat was positively correlated with the level of pubertal development (P<0. 05). The median age of menarche was 12. 11 years. The girls who had had menarche consumed more meat and less diiry products than those who had not yet (P<0. 05). Daily consumption of dairy products was negatively associated with breast development and the level of pubertal development (P < 0. 05)., Conclusion: Consumptions of meat, red meat and dairy products are associated with pubertal development in adolescents in Chengdu. However, the differences between boys and girls warrant further studies.

Objective: To investigate milk consumption and effects on dietary nutrients and growth status among 7 - 17 years-old Chinese children in 9 provinces (autonomous region) from 1991 to 2006., Methods: Data was collected in 1991, 1993, 1997, 2000, 2004 and 2006 China Health and Nutrition Survey, and 11 691 subjects aged 7 to 17 years old were included. The subjects were divided into the following groups according to milk consumption per day, 0 (no milk drinking), 1 - 99, 100 - 199, 200 - 299 and ≥ 300 g/d. Variables from different years were compared, such as milk categories, energy, protein, calcium intake, body mass index (BMI), as well as that dietary nutrients, height and weight among different milk consumption groups., Results: From 1991 to 2006, milk drinking rate and milk consumption among Chinese children had great improvement: milk drinking rate reached to 14.1% (161/1145) in 2006, while that was 3.0% (73/2441) in 1991; milk consumption reached to (26.7 ± 85.0) g/d in 2006, which was 6.8 times of that in 1991 (3.9 ± 31.9) g/d (χ(2) = 474.5, P < 0.01). BMI increased from (17.3 ± 2.9) kg/m(2) in 1991 to (18.5 ± 6.0) kg/m(2) in 2006 (χ(2) = 123.5, P < 0.01). Meanwhile, energy intake decreased from (8653.3 ± 2789.2) kJ/d in 1991 to (8058.3 ± 2866.6) kJ/d in 2006 (χ(2) = 72.6, P < 0.01); protein intake decreased from (63.0 ± 22.8) g/d in 1991 to (57.3 ± 23.1) g/d in 2006 (χ(2) = 71.9, P < 0.01). Average height of 0 (no milk drinking), 1 - 99, 100 - 199, 200 - 299 and ≥ 300 g/d groups were (142.9 ± 16.9), (146.9 ± 18.8), (147.6 ± 16.2), (148.8 ± 16.0), (149.9 ± 15.3) cm, respectively (χ(2) = 29.4, P < 0.01); average weight were (37.1 ± 13.2), (40.3 ± 13.9), (41.3 ± 16.9), (41.7 ± 14.6), (41.4 ± 12.2) kg, respectively (χ(2) = 25.7, P < 0.01)., Conclusion: In the period of 1991 to 2006, milk drinking rate and milk consumption has improved greatly. Main nutrient intake, height and weight increased with milk consumption.

Objective: Energy cost of growth is one of the most important components of Energy Requirements (ER) for children and adolescents. According to the latest research: ER was calculated as adding another 8.6 kJ (2 kcal) for each gram of weight gain during growth. In the 2004 FAO/WHO/UNU report on human energy requirements, which used the data from doubly labeled water (DLW) and heart rate monitoring (HRM) method, proposed the latest daily energy requirements for children and adolescents (1-18 years of age). This article introduces the advances in recent years on the energy requirements of children and adolescents.

Objective: To study the current situation and factors influencing the behavior of fruit and vegetable intake in adolescents, and to discuss health education strategy related to the behavior., Methods: 1677 students were selected from primary school and middle school in urban area of Hangzhou by a multistage sampling method. The behavior of fruit and vegetable intake was surveyed by questionnaires of the patient-centered assessment and counseling for exercise plus nutrition project (PACE+) for adolescent-scale of fruit and vegetable consumption, and analyzed by Transtheoretical Model on the servings of intake, the stage of change, process of change, decisional balance and the current status of self-efficacy., Results: The average intake of fruit and vegetable in adolescents was (3.21 +/- 1.50) servings per day ("one serving" means 100 g cooked vegetable or 100 g fruit). The behavior of consuming fruit and vegetable in most of the adolescents was in the contemplation stage, accounting for 36.91% (619/1677). The process of behavior change, decisional balance (Pros) and self-efficacy existed a positive correlation with the process of stage (r(process) = 0.38, r(decisional balance (Pros)) = 0.26, r(self-efficacy) = 0.33, t values were 16.78, 11.02 and 14.31, P < 0.05). The servings of fruit and vegetable intake existed a positive correlation with stage transition and self-efficacy (beta(stage transition) = 0.665, t = 35.07, P < 0.05; beta(self-efficacy) = 0.050, t = 2.63, P < 0.05), and existed a negative correlation with decisional balance (Cons) (beta(decisional balance (Cons)) = -0.051, t = -2.84, P < 0.05)., Conclusion: Fruit and vegetable intake of these adolescents are under the recommended dietary intake. Along with behavior stage development and self-efficacy improvement, the intake of fruit and vegetable also increased correspondingly. Intervention strategies should aim at improving the awareness of adolescents on the health benefits of fruit and vegetable intake and promoting their confidence to reach the recommended servings.

Objective: To study the secular changes on both morphological development and nutritional status among Tibetan students, from 1985 to 2005., Methods: Data from the Chinese national survey on students' physical fitness and health in 1985, 1995, 2000 and 2005 were used to analyze and find out the difference of the morphological development and nutrition status of Tibetan students aged 7 - 18 years in different years., Results: From 1985 to 2005, the height and weight of Tibetan students had a growing trend. The height and weight of schoolboys and schoolgirls aged 7 - 18 years increased 3.94 cm, 5.08 kg, 2.25 cm, and 4.24 kg respectively, while the circumference decreased without significance. The prevalence rates of underweight and malnutrition in Tibetan students further went down along with the improvement of their nutritional status. However, the prevalence rates on both overweight and obesity increased continuously, affecting the health status of Tibetan students., Conclusion: From 1985 to 2005, the morphological development of Tibetan students had a growing trend and their nutrition status improved. However, the prevalence of overweight and obesity continuously increased.

Objective: To describe the status of snacks consumption, the characteristics, and the contribution to their diet and nutrients intake in Chinese children and adolescents at the ages of 3-17 years., Methods: Chinese health and nutritional survey (1991-2004), Chinese National nutrition and health survey (2002), and 2007 typical survey on snacks in Chinese residents were used in this report. The incidence of snacks consumption and snacking contribution were calculated by consecutive day 3 dietary recalls of the first 2 surveys. At least 1 snacks intake in 3 days was snacking consumption., Results: The incidences of snacks consumption in Chinese population at the ages of 3-17 years were increased from 1991 (13.2%) to 2004 (19.3%). There were 35.1% of Chinese children and adolescents consuming snacks, 55.7% in urban and 29.6% in rural. Snacks provided 7.7% of total daily energy, 18.2% of fiber, 17.9% of VC, 9.9% of calcium, 9.7% of VE, 6.9% of iron and 6.3% of zinc. The snacks were mainly consumed in the evening. The main reasons were not nutrition of food but good taste, thirsty or hungry and food advertisement. The location of snacking was mainly at home and school. The snacks came from parents or other family members. They also buy snacks themselves. The consumption of candies and chocolate, jelly more than 4-6 day a week had a certain proportion., Conclusion: It was important to supervise snacks selection and consumption in Chinese children and adolescents at the ages of 3-17 years. The limitations of snacks consumption data perhaps lowed underestimate the effects of snacks to dietary intake.

Objective: To study the effect of calcium supplementation on absorption rate of zinc and iron by calcium metabolic balance study., Methods: A total of 80 students (12-17 years old) were selected randomly from 320 subjects who had been supplemented with calcium supplementation for one year. 10 boys and 10 girls were randomly selected from each calcium supplementation group to attend a 10-day metabolic balance study. Samples of foods, feces and urine were collected. Calcium, zinc and iron in samples were measured with ICP-AES., Results: There were significant differences of calcium intake, but were no differences of iron and zinc intake for 4 groups. The apparent absorption rate of calcium, iron and zinc in boys and girls were 69.4%, 12.5%, 29.9% and 46.4%, 20.9%, 35.3%, respectively. Absorption rates of iron were associated with pubertal stages. There were no significant differences of absorption of calcium, iron and zinc for 4 groups. Apparent absorption rates of calcium, iron and zinc seemed higher (75.3%, 23.2% and 36.4%) when the level of calcium intake were 600 - 800mg/d in boys., Conclusion: There were no significant effects on absorption rate of iron and zinc when the level of calcium intake was 1400mg/d in 12-17 years old Chinese adolescents. Absorption rates of calcium, iron and zinc seemed higher when the level of calcium intake was 600 - 800mg/d in boys.

Thirty freshmen were randomly enrolled and their blood glucose levels in fasting and one, two and three and a half hours after breakfast with three different kinds of calorie allocation were determined to explore the effects of breakfast quality on their blood glucose levels. Results showed that changes of blood glucose level curve in fasting students was low and horizontal. Blood glucose level after breakfast with carbohydrate as major composition increased significantly one hour after breakfast but could not last for a long time, and decreased rapidly one hour later and down to approximately normal three and a half hours after breakfast. Blood glucose level after breakfast with higher lipid and protein composition increased gradually and maintained at a medium level, and was still higher three and a half hours after breakfast than that with other breakfast; and blood glucose level one hour after breakfast with reasonable calorie allocation increased more rapidly and was kept at a higher and more stable level, and still approximated to that with higher lipid and protein composition three and a half hours after breakfast. It suggests that reasonable allocation of nutrients in breakfast plays an important role in maintaining blood glucose level in the morning, and unhealthy fasting habit in the morning should be abandoned.