High doses of Vitamin-C supplementation show moderate reduction in blood pressure. According to researchers at Johns Hopkins.

Scientists have put much attention on vitamin C’s potential role in blood pressure due to its biological and physiological effects. It may act as a diuretic, causing the kidneys to remove more sodium and water from the body. This helps to relax the blood vessel walls and in turn lowers blood pressure.

Vitamin C-rich plant foods were found to reduce the hardening of the arteries, and thus protect against heart disease and high blood pressure.

According to findings published in the American Journal of Clinical Nutrition, even in people with high blood pressure (hypertension), supplements of vitamin C were associated with systolic and diastolic blood pressure reductions of 4.85 and 1.67 mm Hg.

Today hypertension (high blood pressure) has become one of the main causes of death among adults. One billion people worldwide suffer from high blood pressure, defined as having a systolic and diastolic blood pressure greater than 140 and 90 mmHg. The recent data from the ‘American Heart Association’ shows 33.5% of US adult population suffering from high blood pressure.

Dr. Edgar "Pete" R. Miller, an associate professor in the division of general interal medicine at Hopkins and his team, reviewed and analyzed data from 29 previous clinical trials and found that taking 500 milligrams of Vitamin C daily could lower blood pressure by 3.84 millimeters.

“Although our review found only a moderate impact on blood pressure, if the entire U.S. population lowered blood pressure by 3 milliliters of mercury, there would be a lot fewer strokes,” Miller said in a statement.

“People love to take vitamins regardless of the evidence or lack of it. “We’re trying to raise the bar and provide evidence-based guidance about whether supplements help or actually do harm,” says Miller.

However, Miller warned that none of the studies showed that vitamin C directly prevents or reduces rates of cardiovascular disease, including stroke.

Another study conducted in the University of California, Berkeley, shows that one mg per decilitre increase in blood vitamin C levels was linked to a 4.1 and 4.0 mmHg in systolic and diastolic blood pressures.

The researcher’s recruited 242 women aged between 18 and 21 whose vitamin-C level in blood ranged from 0.22 to 3.13 mg/dL. Two-thirds of the recruited population were African-American, while the other third was Caucasian.

During the period of 10-years of study, the researchers noted that blood vitamin C levels were inversely associated with both systolic and diastolic blood pressure. The effects were still observed after the researchers accounted for the race, body mass index, and dietary intake of fat and sodium of the women.

Surprisingly, intakes of vitamin C do not appear to lower the blood pressure of people whose levels are already normal.

However lot of research is required to corroborate the effects of vitamin C in reducing blood pressure.