By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

The effect of vitamin C (ascorbic acid) on blood pressure and blood lipids has been controversial, although there is evidence that people who consume a lot of vitamin C tend to have a more favorable risk profile for cardiovascular disease. Many elderly people have a relatively low intake of vitamin C.

A study of 40 men and women aged between 60 and 80 investigated the effects of giving 500 milligrams a day of vitamin C or placebo for three months. Blood pressure was measured both in the clinic and by 24-hour ambulatory monitoring, and the effects on blood lipids were also measured. None of the subjects were taking blood pressure-lowering medications. The average clinic blood pressure was 142/88 mmHg at the start of the study, and it was unchanged after taking vitamin C. The average daytime pressure measured by the 24-hour monitors was reduced by 1 mmHg from both systolic and diastolic pressures. In the 17 subjects who were hypertensive at the start of the study, the fall of daytime pressure was 3/3 mmHg.

Total and LDL cholesterol were unchanged after taking vitamin C, but the HDL (good) cholesterol increased from 1.53 to 1.56 mmol/l (59 to 60 mg/dl), a change that was just statistically significant. This increase was more pronounced in women than in men.

Doctor’s comments

These changes of blood pressure and HDL were hardly dramatic, but they were at least in the right direction. A few other studies have also reported a blood pressure lowering effect of vitamin C, although some have found none. Taking vitamin C will not by itself cure hypertension, but it seems reasonable to recommend that older people should maintain an adequate intake of C on the basis of these results.

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