Vitamin C Might Help Lower Hypertension

ByABC News
September 19, 2008, 1:56 PM

Sept. 20 -- FRIDAY, Sept. 19 (HealthDay News) -- Vitamin C may help lower high blood pressure by calming an overactive central nervous system, new Italian research suggests.

Using intravenously delivered vitamin C, "our study demonstrated for the first time in humans that we can reduce sympathetic nervous system overactivity, and consequently blood pressure, (by) targeting oxidative stress," said study lead author Dr. Rosa Maria Bruno from the University of Pisa.

Bruno explained that the sympathetic nervous system (SNS) is part of the body's central nervous system that controls non-voluntary activities, such as blood pressure. Overactivation of the system has been identified as an underlying foundation for the onset of elevated blood pressure and resulting organ damage.

The Italian team was expected to report its findings Friday in Atlanta at the American Heart Association's Conference of the Council for High Blood Pressure Research.

The study builds on prior research touting the potential of vitamin C and other antioxidant nutrients to lower high blood pressure. For example, this past January, British authors presented evidence in The American Journal of Clinical Nutrition that suggested that having high levels of vitamin C in the blood might help reduce stroke risk.

In the current work, Bruno and her colleagues focused on 12 patients diagnosed with an "essential" form of high blood pressure -- namely, one with no known cause.

None of the patients had received any kind of prior treatment for their condition. Over a five-minute period, all the patients were intravenously administered three grams of vitamin C, after which they were monitored for 20 minutes to assess blood pressure and SNS activity. Electrocardiograms were also taken.

The researchers found that "antioxidant capacity" went up as a result of the IV infusions, while SNS activity dropped by about 11 percent.

In addition, the participants' blood pressure was found to have plunged nearly 7 percent on average, with a specific drop in diastolic blood pressure (the bottom number on a reading) of 9 percent. However, no significant drop in systolic blood pressure was observed.