Physical activity and homocysteine in Tswana adolescents : the play : study

Abstract

Plasma homocysteine, a thiol containing amino acid, has been indicated to possibly be a risk factor for various cardiovascular diseases and strokes. Investigators reported normal plasma homocysteiene concentration values of 5 umol/L - 15 µmol/L for adults and a 4 µmol/L - 8 µmol/L for children younger than 12 years. Plasma homocysteine can be influenced by age, gender, ethnicity and lifestyle. Age, gender and ethnicity are factors that can increase plasma homocysteine concentrations. Lifestyle factors such as physical activity, diet, smoking and alcohol seems to affect plasma homocysteine concentrations. Physical activity however, may change plasma homocysteine concentrations but research is needed, to determine the change in plasma homocysteine concentrations. A diet rich in Vitamin B6, B12 and folic acid has been indicated to decrease plasma homocysteine concentrations. Smoking and alcohol consumption contribute to plasma homocysteine concentrations increases but the exact mechanism by which homocysteine concentrations are influenced needs further investigation. The purpose of this study was to examine the homocysteine concentrations for black adolescents and to determine the effect a physical activity intervention programme may have on the plasma homocysteine concentrations of the black adolescents. A intervention study was done on 148 girls and 114 boys from a similar socio — economic status area. Fasting blood samples were taken to determine the plasma homocysteine concentrations. Anthropometric measurements were performed to determine the percentage body fat and muscle mass. A 20 m shuttle-run, was performed on the experimental and control group to establish the fitness level of the subjects. A 10-week physical activity intervention programme was followed, which include muscle endurance and cardio respiratory training. The subjects were retested after the intervention. Descriptive statistics indicated that the experimental and control group presented similar baseline characteristics with regard to the BMI and WHR. Plasma homocysteine concentrations ranged between 5.93 (± 0.92) µmol/L and 7.03 (± 1.67) µmol/L. A significant relation was found between muscle mass and plasma homocysteine concentration (r = 0.25; p = 0.00). Plasma homocysteine increased in the experimental group with 1 % during the 10-week intervention period and with 15 % in the control group. An ANOVA of the changes for the various percentages of compliance to the intervention program indicated that subjects of the experimental group that attended < 33 % and > 66 % of the intervention programme had a significant increase in plasma homocysteine concentration of 7 %. Subjects attending between 33 % and 66 % of the intervention programme reported a 4 % decrease in plasma homocysteine. Plasma homocysteine concentrations were within the recommended range for these adolescents according to the literature. Plasma homocyteine concentrations did not decrease significantly in the experimental and control groups with the physical activity intervention in this study.