Does vitamin C reduce blood pressure? Results of a large study of people aged 65 or older

Abstract

Objective: To characterize relationships among blood pressure, pulse rate, vitamin C status and other protective and risk factors for older British people, from a national survey.

Design: A cross-sectional analysis of survey data.

Setting: A population study, representative of mainland Britain.

Subjects: Among 914 people of both sexes living in the community, 373 were taking blood-pressure-lowering drugs and were therefore excluded from the analyses.

Interventions: Completion of an interview on health, lifestyle and dietary habits, recording of a 4-day dietary record, anthropometry and taking of a blood sample to determine haematological and biochemical status.

Main outcome measures: Systolic and diastolic blood pressures, pulse rate, indices of micronutrient status including plasma ascorbate concentration, nutrient intake and haematology.

Results: Plasma ascorbate concentration was inversely correlated to systolic and diastolic blood pressures and pulse rate. Other covariates of blood pressure included age, sex, domicile, plasma retinol, fibrinogen and gamma-tocopherol concentrations, erythrocyte count, prothrombin time and urine sodium: creatinine ratio. Covariates of pulse rate included sex, domicile, plasma fibrinogen and platelet count. Blood pressure was also correlated to intake of vitamin C.

Conclusions: Plasma ascorbate concentration and intake of vitamin C are covariates of blood pressure in older people living in Britain. New intervention studies are now needed, to test for possible causalities.