Impact of dairy supplementation on bone acquisition in children's limbs: a 12-month cluster-randomized controlled trial and meta-analysis.

The impact of milk on bone health in rural preschoolers is under-researched. This study, through a clinical trial and a meta-analysis, finds that milk supplementation enhances forearm and calcaneus bone acquisition in children, supporting the benefits of daily milk consumption. PURPOSE: This study evaluated the impact of dairy supplementation on bone acquisition in children's limbs through a cluster-randomized controlled trial and a meta-analysis. METHODS: The trial involved 315 children (4-6 year) from Northwest China, randomized to receive either 390 ml of milk daily (n = 215) or 20-30 g of bread (n = 100) over 12 months. We primarily assessed bone mineral density (BMD) and content (BMC) changes at the limbs, alongside bone-related biomarkers, measured at baseline, the 6th and 12th months. The meta-analysis aggregated BMD or BMC changes in the forearm/legs/calcaneus from published randomized trials involving children aged 3-18 years supplemented with dairy foods (vs. control group). RESULTS: Of 278 completed the trial, intention-to-treat analysis revealed significant increases in BMD (4.05% and 7.31%) and BMC (4.69% and 7.34%) in the left forearm at the 6th and 12th months in the milk group compared to controls (P < 0.001). The calcaneus showed notable improvements in BMD (2.01%) and BMC (1.87%) at 6 months but not at 12 months. Additionally, milk supplementation was associated with beneficial changes in bone resorption markers, parathyroid hormone (- 12.70%), insulin-like growth factor 1 (6.69%), and the calcium-to-phosphorus ratio (2.22%) (all P < 0.05). The meta-analysis, encompassing 894 children, indicated that dairy supplementation significantly increased BMD (SMD, 0.629; 95%CI: 0.275, 0.983) and BMC (SMD, 0.616; 95%CI: 0.380, 0.851) (P < 0.05) in the arms, but not in the legs (P > 0.05). CONCLUSION: Milk supplementation significantly improves bone health in children's forearms, underscoring its potential as a strategic dietary intervention for bone development. Trial registration NCT05074836.

[Effects of cold exposure on estrous cycle of female C57BL/6 mice].

OBJECTIVE: To study the effects of cold exposure on estrous cycle of female C57BL/6 mice. METHODS: Twelve healthy female C57BL/6 mice were randomly divided into two groups: control group and cold exposure group, 6 in each group. Cold exposure group was exposed to 4℃, 4 h per day, while control group stayed in normal conditions. Vaginal smears were used to observe the estrous cycle. After 2 weeks, blood and uteri were collected from each mouse after anesthetized and weighted. Serum levels of estradiol(E2), follicle-stimulating hormone(FSH), luteinizing hormone(LH), prolactin(Prl) and progesterone(P) were determined by using mouse ELISA kits. The uterus and ovary pathological slices were prepared to observe the structural changes. RESULTS: Compared with the control group, body weight gain showed no significant differences (P＞0.05). The cold group had significant lower coefficients of uterus and the diestrus phase was significantly increased after cold exposure (P＜0.01). Serum level of FSH in cold group was higher and Prl was lower significantly (P＜0.01). Pathological examination of uterus and ovary showed that uterine glands of cold group were expanded and the amount of follicles was decreased significantly. CONCLUSION: Cold exposure might increase mouse estrous cycle and affect their reproductive function.

[Changes in the physical growth of children aged 3 to 6 years in urban areas of Lanzhou from 2001 to 2010].

OBJECTIVE: To study changes in the physical growth of preschool children aged 3 to 6 yeas in urban areas of Lanzhou from 2001 to 2010. METHODS: Stratified, randomized, cluster sampling was used to collect physical examination data on children from 35 private and public kindergartens located in different urban areas of Lanzhou in 2001, 2006, and 2010. Changes in physical growth were analyzed using body height, body weight and body mass index (BMI) as main indices. Growth retardation, underweight, overweight, emaciation and obesity were screened out using height for age (HAZ), weight for age (WAZ), and weight for height (WHZ) and changes from 2001 to 2010 were analyzed. RESULTS: Body height, body weight and BMI increased from 2001 to 2010 in children at different ages (P<0.05). Body height and weight increased with age, while BMI decreased with age. Mean values of HAZ, WAZ, and WHZ increased over time, showing that prevalence rates of underweight, growth retardation, and emaciation decreased from 2001 to 2010 while those of overweight and obesity increased. CONCLUSIONS: Changes in the physical growth of preschool children in urban areas of Lanzhou from 2001 to 2010 were obvious, with increases in body height and body weight. However, problems such as overweight and obesity emerged. In response, while malnutrition is being solved, attention should be paid to over-nutrition that has an adverse effect on physical growth.

[Survey of feeding patterns in 437 infants from Huining County of Gansu Province].

OBJECTIVE: To investigate the feeding patterns of infants in Huining County, Gansu Province, an economically undeveloped county in China, so as to provide scientific evidence for nutritional intervention. METHODS: By cluster sampling based on the area distribution and the economic state, 437 children from 7 different areas in Huining County, Gansu Province were enrolled. A questionnaire on the feeding patterns within 24 months of age was completed by the caregivers. The addition of nutrient supplements (calcium, zinc, ferri, vitamin AD, etc.) during the last year was investigated using the food frequency questionnaires. RESULTS: The average percentages of breast feeding, mixed feeding and artificial feeding were 45.3%, 40.5% and 14.2% respectively. Delayed introduction of complementary food was the most common. Formula powder was added earliest, at age of 6.4 months. The meats were added latest, at age of 17.2 months. Only 66.8% of infants received an addition of complementary food at age of 4-6 months. Grains, vegetables, fruits and eggs were common complementary additional diets, but fishes and shrimps were seldom provided. The proportion of nutrient supplement use was low. The choice of nutrient supplements in urban districts mainly depended on the physicians' suggestions, but in rural area it depended on the caregivers' experience and media advertisements. CONCLUSIONS: The feeding patterns for the infants are not reasonable in Huining County, Gansu Province. It is important to provide nutritional education and reasonable feeding program for caregivers from economically undeveloped areas.