A study by NIH is the largest prospective study on diet and health ever performed—about 500,000 followed for nine years. In addition to examining nitrate and nitrite intake from processed meat, they also looked at intake from other sources such as fresh meat, eggs and dairy. Nitrite from animal sources, not just processed meats, was associated with an increased risk of kidney cancer, and total intake of nitrate and nitrite from processed meat sources was also associated with kidney cancer risk. The researchers found no associations with nitrate or nitrite intake from plant sources, but nitrates from processed meat was associated with cancer.
Nitrosamines are one of the most potent carcinogens in cigarette smoke. One hot dog has as many nitrosamines as five cigarettes.
