http://lpi.oregonstate.edu/mic/vitamins/riboflavin
Hypertension
Although the etiology of
hypertension is unclear, the methylenetetrahydrofolate reductase (
MTHFR) gene C677T
polymorphismis the main determinant of
homocysteine concentrations and has been related to elevated blood pressure (a marker of hypertension)
(71) and increased risk of
coronary heart disease and vascular accident
(72-74). Since this genetic variant leads to decreased MTHFR activity, individuals with the 677TT genotype may benefit from riboflavin supplementation. In an initial
randomized,
double-blind,
placebo-controlled trial in 77 healthy subjects who had been pre-screened for
MTHFR genotype, riboflavin supplementation (1.6 mg/day for 12 weeks) lowered homocysteine levels in the
MTHFR 677TT genotype group but not in the age-matched 677CC and 677CT groups that exhibited normal plasma homocysteine levels at baseline
(75). Two subsequent randomized, double-blind, placebo-controlled trials investigated the possibility of riboflavin modulating hypertension in premature cardiovascular disease (CVD) patients (pre-screened for the
MTHFR 677C→T polymorphism)
(76, 77). Results showed a significant lowering of blood pressure only in the patients with the 677TT genotype supplemented with riboflavin (1.6 mg/day for 16 weeks) compared to placebo, both on initial examination
(69) and when the same cohort of high-risk CVD patients was reinvestigated four years after the original trial
(70). Another study investigated the effect of riboflavin in 88 hypertensive patients (but without overt CVD) with the
MTHFR 677TT genotype, the majority of whom were being treated with antihypertensive therapy. At baseline, 60% of participants had failed to achieve target BP levels (≤140/90
mm Hg), despite taking three or more antihypertensive medications. The reduction in blood pressure following riboflavin supplementation (1.6 mg/day for 16 weeks) in these patients suggested that the excess risk of hypertension linked to this genetic variation could be overcome by optimizing riboflavin
status (78).