Higher Vitamin C Levels Linked with Lower Blood Pressure
An article published online on July 18, 2011 in the journal Hypertension reveals an association between increased levels of vitamin C and a reduced risk of high blood pressure.
Researchers in England evaluated data from 20,926 men and women aged 40 to 79 years who enrolled in the European Prospective Investigation Into Cancer-Norfolk prospective population study between 1993 and 1997.
Blood pressure, plasma vitamin C and other factors were measured at the participants' initial clinic visit. Questionnaire responses provided information on medical conditions, anti-hypertensive medication use and vitamin C intake from supplements.
For those whose plasma vitamin C levels were among the top 25 percent of participants, the adjusted risk of having hypertension, defined as systolic blood pressure of at least 140 mm Hg, was 22 percent lower than those whose levels were among the lowest fourth.
Exclusion of subjects who used vitamin C supplements or anti-hypertensive drugs failed to modify the finding. Each 20 micromole per liter increase in plasma vitamin C, which is associated with consuming one additional serving of fruit and vegetables daily, was related to a 0.9 mm Hg reduction in systolic blood pressure.
Phyo K. Myint and colleagues remark that vitamin C is a well known antioxidant, and that oxidative stress plays a major role in hypertension. The vitamin also acts as a vasodilator by increasing the bio-availability of nitric oxide.
"The magnitude of the association between fruit and vegetable consumption depicted by plasma vitamin C concentration and blood pressure is considerable and independent of known major risk factors for high blood pressure," the authors write. "Future studies should be focused not only on quantity but on quality and type of fruit and vegetable consumption to better understand the association between dietary lifestyle behavior and blood pressure."
Source: Hypertension Journal - July 18, 2011
Question, if this study ending in 1997, why did it take until July 2011 to be published??