Nitrate: The Dr. Jekyll and Mr. Hyde of human health?

Resumen

Background: Dietary nitrate has a controversial role in human health. For over half a century, the nitrate contentof the three major dietary sources – vegetables, meat, and water – has been legislated, regulated, and monitoreddue to public health concerns over cancer risk. In contrast, a growing and compelling body of evidence indicatesthat dietary nitrate, particularly from vegetables, protects against cardiovascular disease and other chronicdiseases. This evidence for the protective effect of nitrate is overshadowed by the potential for nitrate to formcarcinogenic N-nitrosamines.Scope and approach: The nitrate content, regulations and estimated intake from vegetables, meat and water aredescribed. The evidence that nitrate, through its effects on nitric oxide, improves cardiovascular disease outcomes,cognitive health, musculoskeletal health, and exercise performance as well as the potential to protectagainst other debilitating health outcomes (nitrate as Dr Jekyll) is discussed. The underlying assumption that allnitrate, irrespective of source, leads to the formation of carcinogenic N-nitrosamines and the evidence of anassociation between the different sources of nitrate and cancer (nitrate as Mr Hyde) is examined.Key findings and conclusions: The current theory that nitrate, is a carcinogenic contaminant in meat, water, andvegetables is not fully supported by available evidence. Definitive studies examining the beneficial or harmfuleffects of source-dependent nitrate have yet to be performed. Studies with improved exposure assessment andaccurate characterization of factors that affect endogenous nitrosation are also needed to draw conclusions aboutrisk of cancer from dietary nitrate intake.