Researchers, led by Gladys Block from the University of California, Berkeley, report that a 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 study, said to be the first to report a relationship between blood vitamin C levels and blood pressure in young women with normal blood pressure, is published in the open-access Nutrition Journal.
“Lowering BP or attenuating increases in BP in healthy young adults may lead to lower BP in older adults and reduced risk of age-associated vascular events,” wrote the authors.
“This study suggests that vitamin C may be an important factor in BP regulation even among health young adults, and that further study is warranted.”
High blood pressure (hypertension),defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg, is a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
Block and her co-workers recruited 242 women aged between 18 and 21. Two-thirds of the women were African-American, while the other third was Caucasian. The blood levels of vitamin C of the women ranged from 0.22 to 3.13 mg/dL.
During follow-up over a ten year period, 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.
Indeed, women with the highest vitamin C levels were found to have systolic and diastolic blood pressure 4.66 mmHg and 6.04 mmHg lower than women with the lowest vitamin C levels.
“A 1 mg/dL increase in plasma ascorbic acid levels was associated with 4.1 mmHg lower systolic blood pressure and 4.0 mmHg lower diastolic blood pressure,” wrote Block and her co-workers. “Plasma ascorbic acid levels in this cohort ranged from 0.22 to 3.13 mg/dL, indicating that a 1 mg/dL change in plasma ascorbic acid level is achievable in this young population.”
While the researchers did not perform a study to elucidate the mechanism, they did state that other studies have offered a “substantial biologic rationale for a causal role of ascorbic acid in maintaining normal BP”.
While a potential role for vitamin C may via an antioxidant mechanism, there is also the possibility that he nutrient’s other functions may be having an effect. These include a role in the function of smooth muscle function, or prevention of nitric oxide (a vasodilator or compound that opens up the blood vessels), they said.
Source: Nutrition Journal7:35 doi:10.1186/1475-2891-7-35“Vitamin C in plasma is inversely related to blood pressure and change in blood pressure during the previous year in young Black and White women”Authors: G. Block, C.D. Jensen, E.P. Norkus, M. Hudes, P.B. Crawford