Lowering Homocysteine with B Vitamins Has No Effect on Blood Pressure in Older Adults

Abstract

An elevated circulating homocysteine concentration is associated with the risk of cardiovascular disease. The mechanism by which an elevated homocysteine increases cardiovascular risk is unclear but may be mediated in part by elevating blood pressure. It is well established that supplements containing folate, vitamins B-12, and B-6 lower homocysteine concentrations. However, the effect of homocysteine-lowering vitamins on blood pressure has not been well studied. We sought to determine whether lowering homocysteine with B vitamins lowers blood pressure in healthy older people with elevated homocysteine concentrations. Two hundred seventy-six healthy older participants (> or = 65 y) with a homocysteine > or = 13 micromol/L were randomized to receive a daily supplement containing folate (1 mg), vitamin B-12 (500 microg), and vitamin B-6 (10 mg), or a placebo, for 2 y. Plasma homocysteine was lower in the Vitamins group than the Placebo group at both 1 [-4.3 micromol/L (95% CI; -4.9, -3.7)] and 2 y [-4.4 micromol/L (95% CI: -5.3, -3.6)]. Systolic and diastolic blood pressures as well as pulse pressure in the Vitamins group did not differ from the Placebo group over the duration of the trial. The mean differences in blood pressures, adjusted for baseline values, did not exceed 1 mm Hg. Supplemental B-vitamins lowered plasma homocysteine but had no effect on blood pressure in older people with elevated baseline homocysteine concentrations.

Homocysteine and hydrogen sulfide in epigenetic, metabolic and microbiota related renovascular hypertension

“…Interestingly, in a cross-sectional study it was estimated that higher plasma homocysteine levels at baseline were associated with an increased, but non-significant risk of incidental hypertension in men [140]. A similar result was reported in older adults where lowering homocysteine levels by B vitamins for a period of two years did not change blood pressure significantly compared to placebo control [141]. On the other hand, in a prospective study the progression of blood pressure on normotensive population over 2-years period Wang et al found that homocysteine is related to hypertension incidence at high levels, and may also increase the risk of hypertension at low levels [142].…”

Riboflavin lowers blood pressure in cardiovascular disease patients homozygous for the 677C→T polymorphism in MTHFR

“…Thus, riboflavin may interact with MTHFR to influence blood pressure independently of tHcy, and elevated plasma tHcy may merely be a marker of impaired MTHFR activity in cells rather than being causatively implicated in hypertension. In support of this view, two recent studies showed that despite a marked homocysteine-lowering response to high-dose B-vitamin supplementation (folic acid, vitamin B12, vitamin B6, but not riboflavin) for 2 years, there was no corresponding lowering of blood pressure in healthy older adults [38] or in stroke patients in the Vitamin Intervention for Stroke Prevention (VISP) trial [13]. In contrast, two other intervention trials reported small but significant lowering of blood pressure in response to combined high-dose folic acid and vitamin B6 for 2 years [39] or high-dose folic acid alone for 4 weeks in smokers [40].…”

Relationship between homocysteine and hypertension: New data add to the debate

“…At the end of the first and second years of the study, homocysteine and BP levels were determined. Despite the reductions in homocysteine levels of 4.3 μmol/L at year 1 and 4.4 μmol/L at year 2, no statistically significant reduction in BP was seen …”