Association between intake of soy isoflavones and blood pressure among urban and rural Malaysian adult

ABSTRACT

@#Introduction: Intake of soy isoflavones has been shown to be beneficial in reducing blood pressure, a known cardiovascular risk factor. This study investigated the association between intake of soy isoflavones and blood pressure among multiethnic Malaysian adults. Methods: A total of 230 non-institutionalised Malaysians aged 18-81 years were recruited through multi-stage random sampling from urban and rural areas in four conveniently selected states. Participants were interviewed on socio-demographics, medical history, smoking status, and physical activity. Measurements of height, weight, waist circumference (WC), and blood pressure (BP) were taken. Information on usual intake of soy foods was obtained using a validated semi-quantitative food frequency questionnaire. Results: The mean intake of soy protein of both urban (3.40g/day) and rural participants (3.01g/day) were lower than the USFDA recommended intake level of soy protein (25.00g/day). Urban participants had significantly higher intake of isoflavones (9.35±11.31mg/ day) compared to the rural participants (7.88±14.30mg/day). Mean BP levels were significantly lower among urban (136/81mmHg) than rural adults (142/83mmHg). After adjusting for age, gender, educational level, household income, smoking status, physical activity, BMI and WC, soy protein intake was significantly associated with both SBP (R2=0.205, β=-0.136) and DBP (R2=0.110, β=-0.104), whilst soy isoflavones intake was significantly associated with SBP (β=-0.131). Intake of 1 mg of isoflavone is estimated to lower SBP by 7.97 mmHg. Conclusion: Higher consumption of isoflavones among the urban participants showed an association with lower levels of SBP. Use of biological markers for estimating isoflavones levels is recommended to investigate its protective effects on blood pressure.