Vitamin B2 may benefit people with increased risk of hypertension

Optimizing riboflavin status by supplementation may help patients genetically at-risk of developing hypertension to manage their elevated blood pressure, says a new UK study.

In 2004, 181 patients with cardiovascular disease carrying a genetic variant of a riboflavin-dependent enzyme (MTHFR) were examined in an observational study (1). The study results showed that participants with two gene copies of the modified enzyme had a significant higher risk of elevated blood pressure. Furthermore, providing the patients with 1.6 mg riboflavin for 16 weeks resulted in a significant lowering of blood pressure. Four years later 83 of the patients were examined again, as antihypertensive therapy, which was concurrently administered, had changed in the meantime (2). The results showed that despite the marked changes in drug management of hypertension that had occurred, systolic blood pressure remained unchanged. It was elevated in patients with the gene variation at the time of follow-up. Riboflavin supple-mentation (1.6 mg for 16 weeks) resulted in a significant decrease in systolic and diastolic blood pressure.

The researchers concluded that an optimization of the riboflavin status in patients with increased risk of hypertension due to genetic MTHFR variants may offer a low-cost strategy for managing their elevated blood pressure. These findings, if confirmed in the general population, could have important implications for the prevention of hypertension.

Riboflavin is required as a cofactor for the enzyme methylenetetrahydrofolate reductase (MTHFR) involved in the transformation of homocysteine to methionine. A common genetic variation (polymorphism) results in reduced enzymatic activity and a 20% increase in plasma homocysteine (3), which has been linked with elevated blood pressure (4) and an increased risk of stroke (5). It has been estimated that this polymo-rphism concerns 10% of the people worldwide, ranging from 4% to 18% in the United States, 20% in Northern China, and to as high as 32% in Mexico (6). However, supplementation with riboflavin appears to stabilize the enzyme MTHFR (7).

1. Horigan G. et al. Riboflavin lowers blood pressure in cardiovascular disease patients homozygous for the 677C/T polymorphism in MTHFR. J Hypertens. 2010; 28:478–846.
2. Wilson C. P. et al. Riboflavin offers a targeted strategy for managing hypertension in patients with the MTHFR 677TT genotype: a 4-y follow-up. AJCN. Published online January 2012.
3. Frosst P. et al. A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase. Nat Genet. 1995; 10:111–113.
4. Niu W.-Q. et al. Strong association of methylenetetrahydrofolate reductase gene C677T polymorphism with hypertension and hypertension-in-pregnancy in Chinese: a meta-analysis. J Hum Hypertens. 2011.
5. Holmes M. V. et al. Effect modification by population dietary folate on the association between MTHFR genotype, homocysteine, and stroke risk: a meta-analysis of genetic studies and randomised trials. Lancet. 2011; 378:584–594.
6. Wilcken B. et al. Geographical and ethnic variation of the 677C.T allele of 5,10 methylenetetrahydrofolate reductase (MTHFR): findings from over 7000 newborns from 16 areas world wide. J Med Genet. 2003; 40:
   619–625.
7. McNulty H. et al. Riboflavin lowers homocysteine in individuals homozygous for the MTHFR 677C-.T polymorphism. Circulation. 2006; 113:74–80.