Can a deficiency of nitric oxide raise your blood pressure?
Lower nitric oxide levels are clearly associated with higher blood pressure, both through biological mechanisms and through genetic variants that limit its production. If you have high blood pressure or a family history of it, this is one of the routes that science takes seriously.
Nitric oxide relaxes blood vessels. Less of it means more pressure on the vessel wall and therefore higher blood pressure. This mechanism is well documented: a substance that blocks nitric oxide production (ADMA) has been found at elevated levels in the blood of people who were born prematurely, contributing to their higher blood pressure.
Whether someone produces enough nitric oxide depends in part on the eNOS gene, the gene responsible for the enzyme that makes nitric oxide. People with a particular variant (the 894T allele) show a 16% higher risk of high blood pressure in large analyses compared with people without that variant. In Asian populations that risk rises to 32%, and in Chinese populations to 40%. A second variant (the 4a allele of the same gene) is linked to a 29% increased risk of high blood pressure, again strongest in Asian populations.
This evidence does not yet prove cause and effect: the genetic analyses show a link between variants that limit nitric oxide production and a greater chance of high blood pressure, but they do not directly demonstrate that the deficiency itself drives blood pressure up. The connection is, however, biologically easy to explain. The fact that the effects are strongest in Asian populations also suggests that other environmental or genetic factors play a role.
In practical terms: nitric oxide clearly plays a part in blood pressure regulation, and variants that reduce its production are linked to a higher blood pressure risk. Whether you can meaningfully boost that production through diet or lifestyle is not answered by these sources.
This answer draws on two large analyses together covering nearly a hundred studies and tens of thousands of participants, one study on blood pressure in people born prematurely, and a review in an Indian population. The association is consistent but was measured in research that followed people over time without assigning any intervention, which means cause and effect cannot be fully separated. The findings for Asian and Chinese populations are the most thoroughly documented; for other population groups the picture is thinner.