A 'green' diet-based approach to cardiovascular health? Is inorganic nitrate the answer?

Ingestion of fruit and vegetables rich in inorganic nitrate (NO3-) has emerged as an effective method for acutely elevating vascular nitric oxide (NO) levels through formation of an NO2- intermediate. As such a number of beneficial effects of NO3- and N-2(-) ingestion have been demonstrated including reductions in blood pressure, measures of arterial stiffness and platelet activity. The pathway for NO generation from such dietary interventions involves the activity of facultative oral microflora that facilitate the reduction of inorganic NO3-, ingested in the diet, to inorganic N-2(-). This N-2(-) then eventually enters the circulation where, through the activity of one or more of a range of distinct N-2(-) reductases, it is chemically reduced to NO. This pathway provides an alternative route for in vivo NO generation that could be utilized for therapeutic benefit in those cardiovascular disease states where reduced bioavailable NO is thought to contribute to pathogenesis. Indeed, the cardiovascular benefits of N-2(-) and NO3- are now starting to be translated in patients in several clinical trials. In this review, we discuss recent evidence supporting the potential utility of delivery of NO3- or N-2(-) for the treatment of cardiovascular diseases.