RESUMO
Given the increased prevalence of pediatric obesity and risk of developing chronic disease, there has been great interest in preventing these conditions during childhood by focusing on healthy lifestyle habits, including nutritious eating and physical activity (PA). The purpose of this study was to determine the relationship between PA, body mass index (BMI) and food choices in adolescent males and females. This cross-sectional study, using a survey questionnaire, evaluated 1212 Southern Californian adolescents' self-reported PA, BMI and food frequency. Results revealed that even though males are more active than females, they have higher BMI percentile values (p < 0.05). Females consumed salad, vegetables and fruit more frequently than males (p < 0.05), where males consumed hamburgers, pizza, red meat, processed meat, eggs, fish, fruit juice, soda and whole milk more frequently than females (p < 0.05). Overweight/obese teens consumed red meat, processed meat and cheese more frequently than healthy weight teens (p < 0.05), yet there was no difference in PA between healthy and overweight/obese teens. These results demonstrate that higher levels of PA may not counteract an unhealthy diet. Even though PA provides numerous metabolic and health benefits, this study suggests that healthy food choices may have a protective effect against overweight and obesity. Healthy food choices, along with PA, should be advocated to improve adolescent health by encouraging maintenance of a healthy weight into adulthood.
RESUMO
Background: Epidemiologic, clinical, and experimental studies have suggested that fish oil (FO), a rich source of n-3 (ω-3) polyunsaturated fatty acids, protects against colon cancer. However, this message is confounded by the FDA's warning that the consumption of certain types of fish should be restricted because of contamination with persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides.Objective: We examined FO contaminated with POPs (PCBs, dichlorodiphenyltrichloroethane, and chlordane) compared with unmodified FO on the risk factors of colon cancer development.Methods: Male Sprague-Dawley rats aged 28 d (n = 30) were allocated into 3 groups and fed 15% corn oil (CO), FO, or POP-contaminated FO for 9 wk with a subcutaneous injection of colon carcinogen azoxymethane at weeks 3 and 4. Colonic aberrant crypt foci (ACF) and cell proliferation were enumerated, and the gene expression of inflammation, antioxidant enzymes, and repair enzymes were determined with the use of real-time quantitative polymerase chain reaction analysis.Results: FO-fed rats had a lower number of ACF (mean ± SE: 29 ± 4.0 for FO compared with 53 ± 8.4 for CO and 44 ± 4.6 for POP FO) and higher-multiplicity ACF than the CO and POP FO groups (4.7 ± 0.9 for FO compared with 11 ± 1.5 for CO and 9.6 ± 1.8 for POP FO) (P < 0.05). FO feeding lowered the proliferation index compared with the CO and POP FO feeding groups (18% ± 1.1% for FO compared with 25% ± 1.6% for CO and 23% ± 0.7% for POP FO) (P = 0.009). Superoxide dismutase [2.4 ± 0.6 relative quantification (RQ) for FO compared with 1.2 ± 0.2 RQ for CO and 1.3 ± 0.3 RQ for POP FO] and catalase gene expression (10 ± 2.0 RQ for FO compared with 5.4 ± 1.1 RQ for CO and 6.6 ± 1.5 RQ for POP FO) were higher in the FO group than in the CO and POP FO groups (P < 0.05). There were no differences between CO and POP FO on the variables.Conclusion: These results indicate that POPs in FO reduce the preventive effects of FO on colon carcinogenesis by increasing preneoplastic lesion formation through the downregulation of antioxidant enzyme expression and increasing cell proliferation in rats.