Impaired endothelial function is recognized as an early and modulating process in the pathogenesis of atherosclerotic cardiovascular disease. Endothelial function is easily measurable by non-invasive means and endothelial dysfunction measured non-invasively independently predicts future cardiovascular risk in patients both with and without clinically apparent cardiovascular disease. Conduit vessel endothelial function in humans is commonly quantified by measurement of flow-mediated dilation (FMD) in the brachial artery, which represents the endothelium-dependent relaxation of a conduit artery - typically the brachial artery - due to an increased blood flow. FMD correlates with impaired endothelium-dependent relaxation in the coronary arteries and is a commonly recognized "barometer" of cardiovascular risk. Taken together, these data suggest brachial FMD is an ideal surrogate marker of cardiovascular risk to monitor the effects of Lactobacillus plantarum 299v as proposed in this work.