Plasma lathosterol measures rates of cholesterol synthesis and efficiency of dietary phytosterols in reducing the plasma cholesterol concentration

Abstract Objectives Because the plasma campesterol/cholesterol ratio does not differ between groups that absorb different amounts of cholesterol, the authors investigated whether the plasma Phytosterols (PS) relate to the body's cholesterol synthesis rate measured as non-cholesterol sterol precursors (lathosterol). Method The authors studied 38 non-obese volunteers (58±12 years; Low-Density Lipoprotein Cholesterol ‒ LDL-C ≥ 130 mg/dL) randomly assigned to consume 400 mL/day of soy milk (Control phase) or soy milk + PS (1.6 g/day) for four weeks in a double-blind, cross-over study. PS and lathosterol were measured in plasma by gas chromatography coupled to mass spectrophotometry. Results PS treatment reduced plasma total cholesterol concentration (-5.5%, p < 0.001), LDL-C (-7.6%, p < 0.001), triglycerides (-13.6%, p < 0.0085), and apolipoprotein B (apo B) (-6.3%, p < 0.008), without changing high density lipoprotein cholesterol (HDL-C concentration), but plasma lathosterol, campesterol and sitosterol expressed per plasma cholesterol increased. Conclusions The lathosterol-to-cholesterol plasma ratio predicted the plasma cholesterol response to PS feeding. The highest plasma lathosterol concentration during the control phase was associated with a lack of response of plasma cholesterol during the PS treatment period. Consequently, cholesterol synthesis in non-responders to dietary PS being elevated in the control phase indicates these cases resist to further synthesis rise, whereas responders to dietary PS, having in the control phase synthesis values lower than non-responders, expand synthesis on alimentary PS. Responders absorb more PS than non-responders, likely resulting from responders delivering into the intestinal lumen less endogenous cholesterol than non-responders do, thus facilitating greater intestinal absorption of PS shown as increased plasma PS concentration.

Sedentarismo e variáveis clínico-metabólicas associadas à obesidade em adolescentes / Inactivity and clinical and metabolic variables associated with adolescent obesity

OBJETIVO: Estudar a associação da obesidade com variáveis metabólicas, variáveis clínicas e sedentarismo, em adolescentes pós-púberes de escolas públicas de São Paulo. MÉTODOS: Estudo caso-controle com 128 adolescentes obesos (índice de massa corporal > percentil 95) e 151 adolescentes eutróficos (índice de massa corporal entre percentis 5 e 85). Foram realizados exame físico, avaliação bioquímica e de composição corporal. RESULTADOS Por meio da análise de variância, foi identificado um gradiente nos valores médios das variáveis metabólicas e clínicas com piora dessas variáveis em paralelo ao aumento do grau de sedentarismo, o que foi confirmado pelo teste qui-quadrado. Na análise bivariada de riscos para obesidade, os adolescentes obesos apresentaram maiores frequências de sedentarismo, de alterações nos níveis de lipoproteína de alta densidade e triglicérides, de hiperinsulinemia e homeostasis model assessment for insulin resistence alterado, e de pressão arterial alterada (p<0,05). O modelo logístico múltiplo mostrou associações entre obesidade e variáveis de sedentarismo (OR=2,23), lipoproteína de alta densidade reduzida (OR=3,05), pressão arterial alterada (OR=3,57), triglicerídeos aumentados (OR=4,13) e homeostasis model assessment for insulin resistence aumentado (OR=11,65). CONCLUSÃO: Sedentarismo, lipoproteína de alta densidade reduzida, hipertrigliceridemia, resistência insulínica e hipertensão estão fortemente associados com a obesidade em adolescentes. Estratégias para redução do peso corporal por meio de mudanças nos hábitos de vida devem fazer parte das políticas e programas de saúde pública, especialmente para essa faixa etária.

OBJECTIVE: This study investigated the association of obesity with metabolic and clinical variables and inactivity in post-pubertal adolescents attending public schools in São Paulo City. METHODS: This was a case-control study with 128 obese adolescents (body mass indices >the 95th percentile), and 151 normal weight adolescents (body mass indices between the 5th and 85th percentiles). Physical examination and biochemical and body composition assessments were done. A pretested questionnaire was administered, generating an inactivity score. Analysis of variance was performed with multiple comparison tests (Bonferroni and Pearson's chi-Square). A multiple regression model was used to ascertain the association among clinical variables, metabolic variables, inactivity score and nutritional status. RESULTS: Analysis of variance allowed the identification of a gradient of mean metabolic and clinical variables which worsened as activity decreased, confirmed by the chi-square test. In the bivariate analysis for obesity risk, obese adolescents were more frequently inactive, presented low high-density lipoprotein and high triglyceride levels, hyperinsulinemia, high homeostasis model assessment for insulin resistance, and high blood pressure (p<0.05). The multiple logistic model showed associations between obesity and inactivity (OR=2.23), low high-density lipoprotein levels (OR=3.05), high blood pressure (OR=3.57), high triglyceride levels (OR=4.13) and high homeostasis model assessment for insulin resistance (OR=11.65). CONCLUSION: Inactivity, low high-density lipoprotein, hypertriglyceridemia, insulin resistance and hypertension are strongly associated with obesity in adolescents. Strategies to reduce body weight by changing life habits should be part of public health programs and policies, especially for this age group.

Riscos cardiovasculares em adolescentes com diferentes graus de obesidade / Cardiovascular risks in adolescents with different degrees of obesity / Riesgos cardiovasculares en adolescentes con diferentes grados de obesidad

FUNDAMENTO: Há poucos estudos sobre riscos cardiovasculares em adolescentes com diferentes graus de obesidade. OBJETIVO: Avaliar repercussões metabólicas associadas a diferentes graus de obesidade em adolescentes e seu impacto nos riscos cardiovasculares. MÉTODOS: Estudo transversal com 80 adolescentes obesos, divididos em dois grupos: 2

BACKGROUND: There have been few studies on cardiovascular risk factors in adolescents with different degrees of obesity. OBJECTIVE: To evaluate metabolic effects associated with different degrees of obesity in adolescents and their impact on cardiovascular risks. METHODS: Cross-sectional study of 80 obese adolescents, divided in two groups: 2

FUNDAMENTO: Existen pocos estudios sobre riesgos cardiovasculares en adolescentes con diferentes grados de obesidad. OBJETIVO: Evaluar repercusiones metabólicas asociadas a diferentes grados de obesidad en adolescentes y su impacto en los riesgos cardiovasculares. MÉTODOS: Estudio transversal con 80 adolescentes obesos, divididos en dos grupos: 2