Effects of folic acid on the human microcirculation: a randomized, doubleblind, placebo-controlled study.

Background:

Folates may have beneficial effects on cardiovascular risk.
Firstly, folate status is an important determinant of plasma homocysteine concentration, which is associated with an increased risk of cardiovascular disease (CVD). Moreover, epidemiologic studies have identified an association between folate status and CVD that is statistically independent of homocysteine. Folate has also been linked to hypertension and insulin resistance.

Thus, the association between folate and CVD may be explained both by direct effects of folate on the vessel wall, as well as by indirect effects, including detrimental effects on blood pressure and insulin sensitivity. Intervention trials using folates, mostly in secondary prevention settings, are yet inconclusive with regard to cardiovascular morbidity and mortality.
As an alternative to clinical endpoint studies, the effects of folates on the vascular system may be studied using surrogate endpoints. One of these surrogate endpoints is microcirculatory function. The prognostic value of microcirculatory dysfunction for clinical cardiovascular endpoints remains to be established. However, several risk factors for CVD are correlated to microcirculatory function, such as hypertension, insulin resistance and obesity.

No previous studies have addressed the question of whether folate supplementation influences the human microcirculation.

Folate supplementation improves microcirculatory function in subjects susceptible to microcirculatory dysfunction.

N/A

1. Folic acid 0,5 mg daily during 8 weeks;

2. 5-methyltetrahydrofolate 5 mg once.