Changes in Fitness of Rural Primary School Students from Southwest China after Two-Year’s Nutrition Intervention

Children in China’s poor rural areas often have insufficient protein and micronutrient intake. There is little research about the effect of milk and egg supplementation published on these children. A prospective randomized controlled trial was applied to evaluate the effect of milk and egg supplementation on the growth and fitness of poor rural primary school students in southwest China whose physical development was below national averages. A total of 955 healthy students aged 6–13 years old were recruited. The intervention group (538) received 200 g milk and 50 g braised egg at each school day, while the control group (417) kept their normal diet and received no extra supplementation. Serum vitamin D levels were measured by an enzyme-linked immunosorbent assay. A mixed linear model with repeated measures was performed to analyze the efficacy of the supplementation. Statistically significant interactions between groups and time were seen in weight in boys, but not in girls. Significant improvement in vitamin D levels, the broad jump, and the 8 × 50 m shuttle run were observed in both genders. Therefore, the supplementation of egg and milk for two years might have a positive effect on growth and physical fitness and decreasing vitamin D deficiency in poor rural Chinese children.