Substitution of whole cows' milk with defatted milk for 4 months reduced serum total cholesterol, HDL-cholesterol and total apoB in a sample of Mexican school-age children (6-16 years of age).

We carried out this study to compare the effect of consuming whole, partially defatted and defatted cows' milk for 4 months on serum concentrations of blood indicators of cardiovascular risk (CVR) in Mexican children and adolescents. Children aged between 6 and 16 years living in indigenous boarding schools in Mexico and who were usual consumers of whole milk were recruited to this study. Totally, thirteen boarding schools were randomly selected to receive full supplies of whole, partially defatted and defatted cows' milk for 4 months. Serum total cholesterol (TC), TAG, HDL-cholesterol, apoA and total apoB, and Lp(a) concentrations were measured before and after the intervention. Comparisons were made with multi-level mixed-effects linear regression models using the difference in differences approach. Compared with the whole milk group, TC, LDL-cholesterol, HDL-cholesterol and total apoB were lower in defatted milk consumers by -0·43, -0·28, -0·16 mmol/l and -0·05 g/l, respectively (all P<0·001). Compared with the whole milk group, the group that consumed partially defatted milk showed a significant decrease in the concentrations of LDL-cholesterol (-0·12, P=0·01), apoA (-0·05 g/l, P=0·01) and total apoB (-0·05 g/l, P=0·001). Defatted milk intake for 4 months reduced some of the serum indicators of CVR.

Defatted milk is preferred by Mexican school-age children over whole milk in a sensorial study.

OBJECTIVE: To compare the liking, flavor and texture of whole, partially defatted and defatted cow's milk using sensory tests. MATERIALS AND METHODS: Children aged 6-16 years, living in indigenous boarding schools in the State of Hidalgo, Mexico, tested samples of whole, partially defatted and defatted cow's milk and answered a questionnaire that explored liking, flavor and texture through ad hoc designed scales. The differences in response proportions were analyzed by χ² tests and multinomial logistic regression models. RESULTS: Tests were completed by 165 children (79 girls and 86 boys). Rated by habitual consumers of whole, partially defatted and defatted milk, liking (70.6-77.8%, liked it very much), flavor (72.5-77.8%, very tasteful) and texture (41.3-54.9%, not creamy or watery) were better rated for defatted than for whole milk [liking (19.6-29.4%, p < 0.001, liked it very much), flavor (19.6-39.7%, p < 0.001, very tasty) and texture (27.5-39.2%, p < 0.05, not creamy or watery)]. The global preference was higher for defatted (74.5-81.0%) than for whole milk (6.3-15.7%, p < 0.001). CONCLUSIONS: Defatted milk (0.5%) can be introduced into public programs to reduce the saturated fat intake or control obesity in children older than 6 years in elementary schools.

Physical activity and fat mass gain in Mexican school-age children: a cohort study.

BACKGROUND: In México, the prevalence of unhealthy weight increased from 24% at 6 y to 33% at 12 y of age, opening a window of opportunity to better understand the pathogenesis of obesity. The objective of this study was to explore the association between time spent on medium, vigorous physical activity (MVPA) and concurrent gains in BMI, fat mass (FM) and fat-free mass (FFM), alternately, in a cohort of Mexican children followed from kindergarten (baseline) to 2nd grade elementary school (endline). METHODS: The MVPA (5-d accelerometry), BMI, FM and FFM (air displacement plethysmography) were measured at baseline and endline. Associations between gains in BMI, FM and FFM and changes in MVPA were examined using lagged and dynamic regression models, controlling for energy intake and demographic variables. RESULTS: A total of 205 children were analyzed. Gender affected the effect of MVPA on FM gain. In girls, a high baseline MVPA predicted a lower FM gain (-0.96 kg, p=0.025) compared to low/medium MVPA. Increasing, decreasing or having a persistently high MVPA predicted a lower FM gain (range -1.6 to -1.03 kg, p<0.05) compared to persistently low MVPA. In boys, increases in MVPA were associated with higher gains in BMI (+0.76 kg/m2, p=0.04) and FFM (+1.1 kg, p=0.01) compared to persistently low MVPA. CONCLUSION: These results support a protective role of MVPA on FM gain in girls, suggesting that it may play a crucial role in the development of obesity. Further research on the gender effect of MVPA is warranted to better understand its role in the prevention and control of overweight and obesity.

The physical activity level of Mexican children decreases upon entry to elementary school.

OBJECTIVE: To compare the physical activity patterns of a cohort of Mexican children in kindergarten (K), first (1ES) and second grade (2ES) of elementary school. MATERIAL AND METHODS: The physical activity of 217 children (123 girls and 94 boys) aged 5-6 years was measured (five full-day triaxial accelerometry) annually.Weekday and weekend moderate/ vigorous physical activity (MVPA) and school and off-school MVPA was calculated. Comparisons between surveys were made using longitudinal multilevel generalized linear models. RESULTS: Weekday MVPA was 22 and 37 min/d lower for 1ES (p=0.06) and 2ES (p<0.01), respectively, compared to K. School MVPA for 1ES and 2ES was 37 (-5.0 min/h) and 40% (-5.5 min/h) (p<0.001) lower, respectively, compared to K. No differences were found between weekend and off-school MVPA among school stages (p>0.5). CONCLUSION: MVPA was significantly reduced from K to ES,in part because of a decline in MVPA during school activities. Interventions targeted to school environment modifications should be promoted.

The physical activity level of Mexican children decreases upon entry to elementary school / El nivel de actividad física disminuye en niños mexicanos al ingresar a la escuela primaria

OBJECTIVE: To compare the physical activity patterns of a cohort of Mexican children in kindergarten (K), first (1ES) and second grade (2ES) of elementary school. MATERIAL AND METHODS: The physical activity of 217 children (123 girls and 94 boys) aged 5-6 years was measured (five full-day triaxial accelerometry) annually.Weekday and weekend moderate/ vigorous physical activity (MVPA) and school and off-school MVPA was calculated. Comparisons between surveys were made using longitudinal multilevel generalized linear models. RESULTS: Weekday MVPA was 22 and 37 min/d lower for 1ES (p=0.06) and 2ES (p<0.01), respectively, compared to K. School MVPA for 1ES and 2ES was 37 (-5.0 min/h) and 40 percent (-5.5 min/h) (p<0.001) lower, respectively, compared to K. No differences were found between weekend and off-school MVPA among school stages (p>0.5). CONCLUSION: MVPA was significantly reduced from K to ES,in part because of a decline in MVPA during school activities. Interventions targeted to school environment modifications should be promoted.

OBJETIVO: Comparar los patrones de actividad física (AF) en una cohorte de niños mexicanos en el jardín de niños, primer y segundo grado de primaria. MATERIAL Y MÉTODOS: Se midió anualmente la AF (acelerometría triaxial de cinco días completos) en 217 niños (123 niñas y 94 niños) de 5 a 6 años de edad. Se calculó la AF moderada/vigorosa (AFMV) entre semana y de fin de semana, dentro y fuera del horario escolar. Se realizaron comparaciones mediante modelos lineales generalizados multinivel longitudinales. RESULTADOS: La AFMV entre semana fue 22 (p=0.06) y 37 min/d (p<0.01) menor, y la AFMV durante el horario escolar disminuyó 37 (-5.0 min/h) y 40 por cento (-5.5 min/h) (p<0.001), en 1º y 2º de primaria,respectivamente,comparado con el jardín de niños.No se encontraron diferencias en la AFMV de fin de semana o fuera del horario escolar entre los grados escolares (p>0.05). CONCLUSIONES: La AFMV disminuyó de manera significativa del jardín de niños a 2º de primaria en parte debido a una reducción de AFMV durante las actividades escolares. Es necesaria la promoción de intervenciones enfocadas a la modificación del ambiente escolar.