Courtney E. Byrd-Williams

Dietary and Activity Correlates of Sugar-Sweetened Beverage Consumption Among Adolescents

OBJECTIVE: To examine the dietary and activity correlates of sugar-sweetened beverage consumption by children in middle and high school. METHODS: Data were obtained from a cross-sectional survey of 15 283 children in middle and high schools in Texas. Consumption of sodas and noncarbonated flavored and sports beverages (FSBs) were examined separately for their associations with the level of (1) unhealthy food (fried meats, French fries, desserts) consumption, (2) healthy food (vegetables, fruit, and milk) consumption, (3) physical activity including usual vigorous physical activity and participation in organized physical activity, and (4) sedentary activity, including hours spent watching television, using the computer, and playing video games. RESULTS: For both genders, consumption of soda and FSBs was systematically associated with a number of unhealthy dietary practices and with sedentary behaviors. However, consumption of FSBs showed significant positive graded associations with several healthy dietary practices and level of physical activity, whereas soda consumption showed no such associations with healthy behaviors. CONCLUSIONS: Consumption of FSBs coexists with healthy dietary and physical activity behaviors, which suggests popular misperception of these beverages as being consistent with a healthy lifestyle. Assessment and obesity-prevention efforts that target sugar-sweetened beverages need to distinguish between FSBs and sodas.

Randomized control trial to improve adiposity and insulin resistance in overweight Latino adolescents.

Few randomized trials attempt to improve insulin sensitivity and associated metabolic risks in overweight Latino youth. The purpose of this study is to examine the effects of a modified carbohydrate nutrition program combined with strength training on insulin sensitivity, adiposity, and other type 2 diabetes risk factors in overweight Latino adolescents. In a 16‐week randomized trial, 54 overweight Latino adolescents (15.5 ± 1.0 years) were randomly assigned to: (i) Control (C; n = 16), (ii) Nutrition (N; n = 21), or (iii) Nutrition + Strength training (N+ST; n = 17). The N group received modified carbohydrate nutrition classes (once per week), while the N+ST received the same nutrition classes plus strength training (twice per week). The following were measured at pre‐ and postintervention: strength by 1‐repetition maximum, dietary intake by 3‐day records, body composition by dual‐energy X‐ray absorptiometry, glucose/insulin indices by oral glucose tolerance test (OGTT) and intravenous glucose tolerance test with minimal modeling. Across intervention group effects were tested using analysis of covariance with post hoc pairwise comparisons. A significant overall intervention effect was found for improvement in bench press (P < 0.001) and reductions in energy (P = 0.05), carbohydrate (P = 0.04) and fat intake (P = 0.03). There were no significant intervention effects on insulin sensitivity, body composition, or most glucose/insulin indices with the exception of glucose incremental area under the curve (IAUC) (P = 0.05), which decreased in the N and N+ST group by 18 and 6.3% compared to a 32% increase in the C group. In conclusion, this intense, culturally tailored intervention resulted in no significant intervention effects on measured risk factors with the exception of a beneficial effect on glycemic response to oral glucose.

Aerobic and strength training reduces adiposity in overweight Latina adolescents.

PURPOSE To date, no study has examined the synergistic effects of a nutrition and combination of aerobic and strength training (CAST) on both adiposity and metabolic parameters in overweight Latina adolescent females. The goal was to assess if a 16-wk nutrition plus CAST pilot study had stronger effects on reducing adiposity and on improving glucose/insulin indices compared with control (C), nutrition only (N), and a nutrition plus strength training (N + ST) groups. METHODS In a 16-wk randomized trial, 41 overweight Latina girls (15.2 +/- 1.1 yr) were randomly assigned to C (n = 7), N (n = 10), N + ST (n = 9), or N + CAST (n = 15). All intervention groups received modified carbohydrate nutrition classes (once a week), whereas the N + ST also received strength training (twice a week) and the N + CAST received a combination of strength and aerobic training (twice a week). The following were measured before and after intervention: strength by one repetition maximum, physical activity by the 7-d accelerometry and the 3-d physical activity recall, dietary intake by 3-d records, body composition by dual-energy x-ray absorptiometry (DEXA), glucose/insulin indices by oral glucose tolerance test, and intravenous glucose tolerance test with minimal modeling. Across intervention group, effects were tested using ANCOVA with post hoc pairwise comparisons. RESULTS There were significant overall intervention effects for all adiposity measures (weight, body mass index [BMI], BMI z-scores, and DEXA total body fat), with a decrease of 3% in the N + CAST group compared with a 3% increase in the N + ST group (P < or = 0.05). There was also an intervention effect for fasting glucose with the N group increasing by 3% and the N + CAST group decreasing by 4% (P < or = 0.05). CONCLUSION The CAST was more effective than nutrition alone or nutrition plus strength training for reducing multiple adiposity outcomes and fasting glucose in overweight Latina girls. However, further research investigating and identifying intervention approaches that improve both adiposity and insulin indices, particularly in high-risk populations, are warranted.

Reduction in Risk Factors for Type 2 Diabetes Mellitus in Response to a Low-Sugar, High-Fiber Dietary Intervention in Overweight Latino Adolescents

OBJECTIVE To examine if reductions in added sugar intake or increases in fiber intake in response to a 16-week intervention were related to improvements in metabolic outcomes related to type 2 diabetes mellitus risk. DESIGN Secondary analysis of a randomized control trial. SETTING Intervention classes at a lifestyle laboratory and metabolic measures at the General Clinical Research Center. PARTICIPANTS Fifty-four overweight Latino adolescents (mean [SD] age, 15.5 [1] years). Intervention Sixteen-week study with 3 groups: control, nutrition, or nutrition plus strength training. MAIN OUTCOME MEASURES Body composition by dual-energy x-ray absorptiometry; visceral adipose tissue by magnetic resonance imaging; glucose and insulin incremental area under the curve by oral glucose tolerance test; insulin sensitivity, acute insulin response, and disposition index by intravenous glucose tolerance test; and dietary intake by 3-day records. RESULTS Fifty-five percent of all participants decreased added sugar intake (mean decrease, 47 g/d) and 59% increased fiber intake (mean increase, 5 g/d), and percentages were similar in all intervention groups, including controls. Those who decreased added sugar intake had an improvement in glucose incremental area under the curve (-15% vs +3%; P = .049) and insulin incremental area under the curve (-33% vs -9%; P = .02). Those who increased fiber intake had an improvement in body mass index (-2% vs +2%; P = .01) and visceral adipose tissue (-10% vs no change; P = .03). CONCLUSIONS Individuals who reduced added sugar intake by the equivalent of 1 can of soda per day or increased fiber intake by the equivalent of a cup of beans showed improvements in key risk factors for type 2 diabetes, specifically in insulin secretion and visceral fat. Improvements occurred independent of group assignment and were equally likely to occur in control group participants.

Dietary Intake and the Metabolic Syndrome in Overweight Latino Children

Little is known about the relationship between diet and metabolic health in Latino children, a population at increased risk for diabetes. The present study evaluates diet composition and the metabolic syndrome in a cross-sectional sample of 109 overweight Latino children aged 10 to 17 years with a family history of type 2 diabetes. Dietary intake was assessed by two 24-hour recalls. Associations between nutrients and features of the metabolic syndrome were examined using multiple linear regression and analysis of covariance. Log cholesterol intake was positively associated with log systolic blood pressure (beta=0.034, P=0.017) and log soluble dietary fiber intake was inversely associated with log waist circumference (beta=-0.069, P=0.036). Log soluble fiber intake was significantly higher in participants with 0 features compared to those with 3+ features of the metabolic syndrome (P=0.046), which translates to 5.2 g vs 4.1 g soluble fiber daily. No other significant associations were found between dietary variables and either the individual features of the metabolic syndrome or the clustering of metabolic syndrome components. Increases in soluble fiber through the daily consumption of fruits, vegetables, and beans may improve metabolic health in Latino children.

Randomized Controlled Trial to Improve Adiposity, Inflammation, and Insulin Resistance in Obese African-American and Latino Youth

The purpose of this study was to examine ethnic differences in the metabolic responses to a 16‐week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African‐American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre‐ and postintervention: strength, dietary intake, body composition (dual‐energy X‐ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. −32.3% vs. −6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. −14.2% vs. −13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: −27.3% vs. −4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor‐1 (PAI‐1) (−38.3% vs. +1.0%, P < 0.01) and resistin (−18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2‐h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (Ps < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.

Physical activity, sedentary behavior, and the metabolic syndrome in minority youth.

PURPOSE This study aimed to determine the associations among physical activity, sedentary behavior, and the metabolic syndrome (MetS) in Latino and African American youth using both subjective and objective measures of activity levels. METHODS Cross-sectional data from 105 participants from three pediatric obesity studies that share a core set of methods and measures (Latino 74%, female 75%, mean age = 13 ± 3 yr) were used. Measures included moderate-to-vigorous physical activity and sedentary behavior by accelerometry and 3-Day Physical Activity Recall (3DPAR), fat and lean tissue mass by BodPod™, fasting glucose, lipids, blood pressure, and waist circumference. Associations between physical activity, sedentary behavior, and MetS were examined using ANCOVA, Pearson correlations, partial correlations, and logistic regressions with adjustments for age, sex, ethnicity, fat and lean mass, and pubertal Tanner stage. RESULTS Accelerometry data showed that greater time engaging in moderate-to-vigorous physical activity was related to lower odds of the MetS (odds ratio = 0.49, 95% confidence interval = 0.25-0.98), independent of sedentary behavior and covariates, and inversely correlated with fasting glucose (r = -0.21, P = 0.03) and systolic blood pressure (r = -0.25, P = 0.01), adjusting for covariates. Data from the 3DPAR showed that higher levels of sedentary behavior were related to higher odds of the MetS (odds ratio = 4.44, 95% confidence interval = 1.33-14.79), independent of moderate-to-vigorous physical activity and covariates, negatively correlated with HDL-cholesterol (r = -0.21, P = 0.04) and positively correlated systolic blood pressure (r = 0.26, P = 0.009), adjusting for covariates. CONCLUSIONS Future interventions aiming to improve metabolic health in youth should target both the promotion of physical activity and the reduction of sedentary behavior. Subjective and objective measures should be used in conjunction to better capture activity behaviors.

Influence of gender, BMI and Hispanic ethnicity on physical activity in children

OBJECTIVE The purpose of this study was to examine the association between overweight status and physical activity (PA) among gender and ethnic (Hispanic vs. non-Hispanic) sub-groups in elementary school-age children. METHODS PA was assessed over five days using the Actigraph accelerometer in 169 fourth grade students (mean age 9.4 years; 50% female; 63% Hispanic; and 43% overweight, defined as body mass index, BMI > or = 85th percentile for age and gender) from four elementary schools in Los Angeles County, California. RESULTS In the total sample, boys and normal weight students had higher levels of total PA (counts per minute, cpm; p<0.05). Boys spent less time in sedentary PA (p=0.02) and more time in combined moderate to vigorous PA (MVPA, p=0.01). There was a significant gender, ethnicity, and overweight interaction for total PA and MVPA (both p<0.01). MVPA and counts per minute were significantly lower in overweight non-Hispanic girls and Hispanic boys (p<0.05) and marginally lower in overweight non-Hispanic boys (p=0.10) when compared with non-overweight students, while overweight Hispanic girls were more physically active than Hispanic non-overweight girls, though the difference was non-significant (p>0.05). CONCLUSIONS Data from the present study does not consistently support the prevailing hypothesis that overweight subjects engage in less PA. Results show overweight students engage in less PA than non-overweight students, with the exception that non-overweight Hispanic girls do not engage in more PA than their overweight peers. These results suggest the need for further investigation into the role that ethnicity and overweight status plays in PA levels, particularly among ethnic and gender sub-groups.

Nutrition-Related Knowledge, Attitudes, and Dietary Behaviors among Head Start Teachers in Texas: A Cross-Sectional Study

Head Start teachers are responsible for providing nutrition education to over 1 million low-income children annually, yet little is known about their nutrition-related knowledge, attitudes, and behaviors. The purpose of this study is to assess the self-reported nutrition knowledge, attitudes, and behaviors among Head Start teachers from one urban Head Start organization in Harris County, TX. A cross-sectional, descriptive analysis was conducted using baseline surveys in the 2008-2009 school year. One hundred eighty-one Head Start teachers completed self-reported surveys of their nutrition knowledge, attitudes, behaviors, weight status, and other weight-related behaviors. The sample was predominantly female (97%) and minority (93%); 24% were overweight and 55% were obese. One fourth of the sample did not consume fruit (26%) or vegetables (23%) the previous day. Half of the teachers reported consuming french fries (52%) and soda (44%), and one fourth consumed fried meat (28%) at least once on the previous day. Only four teachers (3%) answered at least four of the five nutrition knowledge questions correctly. Half of the teachers (54%) agreed that it was hard to know which nutrition information to believe, and only 9% reported that their nutrition habits were healthy. A majority of teachers were trying to lose weight (71%) and said they would like to weigh less (81%). This study underscores the importance of providing nutrition education and wellness opportunities to Head Start teachers to better enable them to teach nutrition education to their students and to improve their own health.

Effects of a randomized maintenance intervention on adiposity and metabolic risk factors in overweight minority adolescents

The objective of this study was to assess the effects of a maintenance programme (monthly newsletters vs. monthly group classes and telephone behavioural sessions) on obesity and metabolic disease risk at 1 year in overweight minority adolescents.