In contrast to nitrite, nitrate in the diet comes mainly from cured meats such as bacon, sausage and luncheon meats. Consuming nitrate augments our nitrite supply: Once absorbed in the bloodstream, nitrate circulates to the salivary glands where bacteria convert it to nitrite, which is then swallowed in our saliva. About 10 percent of dietary nitrate is converted to nitrite in this way.
As with the mice and nitrite, the Einstein researchers spiked drinking water with nitrate and then induced heart attacks. A protective effect was found yet again: Compared with the control animals, the nitrate-supplemented mice had greater stores of nitrite in their heart muscle along with significantly less heart-muscle damage, although the reduction was not as impressive as in the nitrite-fed mice.
“This new appreciation of the health benefits of nitrite and nitrate is ironic,” says Dr. Lefer, “They’ve traditionally been regarded as toxic because they tend to form chemicals called nitrosamines, some of which are carcinogenic. But recent research has found no convincing evidence that nitrite and nitrate pose a cancer risk.”