Jan 14, 2009 (foodconsumer.org) -- A new study by researchers at the University of California Berkeley suggests that high intake of vitamin C may help prevent high blood pressure in young women.

The study published in the open-access Nutrition Journal found that each 1 mg/dL increase in serum vitamin C was linked to a drop of 4.1 and 4.0 mmHg in systolic and diastolic blood pressure respectively.

For the study, Gladys Block and colleagues examined the association between serum vitamin C levels, which ranged from 0.22 to 3.13 mg/dL, and blood pressure in 242 women aged 18 to 21 of whom two thirds were African-American and the rest Caucasian.

During the 10-year follow-up, the researchers found in young women serum vitamin C levels were inversely associated with both systolic and diastolic blood pressure. The associations were significant even after cofounders were also considered.

Specially, systolic and diastolic blood pressures in women with the highest serum vitamin C were 4.66 mmHg and 6.04 mmHg lower respectively compared to those with the lowest levels.

An early Italian study found that vitamin C intravenously delivered can lower blood pressure by acting on an overactive central nervous system.

Dr. Rosa Maria Bruno from the University of Pisa, coauthor of the study, said quoted by healthday.com, "our study demonstrated for the first time in humans that we can reduce sympathetic nervous system over-activity, and consequently blood pressure, (by) targeting oxidative stress."

The sympathetic nervous system (SNS) is part of the central nervous system that controls blood pressure among other things.     Low activity of the SNS is coupled with the onset of elevated blood pressure.

The finding was presented Friday at the American Heart Association's Conference of the Council for High Blood Pressure Research held in Atlanta.

The current study involved 12 patients with an essential form of high blood pressure who had not received any treatment for their high blood pressure.    All the participants were intravenously administered three grams of vitamin C during a period of five minutes and then monitored for blood pressure and SNS activity for 20 minutes.

It was found that SNS activity dropped by 11 percent and blood pressure was lowered by about 7 percent on average.    The decrease in diastolic blood pressure was 9 percent while systolic blood pressure did not change significantly.

Vitamin C is known to boost the production of nitric oxide, which can affect blood vessels and lower blood pressure, early studies suggested.   Nitric oxide (NO) contributes to vessel homeostasis by inhibiting vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium, according to wikipedia.