Brenda Spriggs, MD, MPH, MBA
Sodium nitrite is a chemical found naturally in many vegetables, including spinach, lettuce, cauliflower and beets. It is a common preservative and coloring agent in foods such as cured meats. Nitrite levels in foods concern health care professionals and lay people alike; however, the effects of sodium nitrite, whether from your diet or from medical treatment, may be positive or negative, depending on the circumstance.
Sodium nitrite is a potent vasodilator, causing the smooth muscles of your arterial walls to relax, explains Dr. David Casey in the February 2009 issue of the "American Journal of Physiology-Heart and Circulatory Physiology." This effect occurs when sodium nitrite is converted to nitric oxide, a chemical that's important in regulating your blood vessels, and sodium nitrite may be a storage form of nitric oxide within your cells. Dr. Mark Gladwin of the Vascular Therapeutic Section of the Cardiology Branch of the National Heart, Lung and Blood Institute reports that sodium nitrite is potentially an effective and inexpensive treatment for brain aneurysms, heart attacks, pulmonary hypertension and sickle cell anemia.
Sodium nitrite helps preserve cured meats, such as bacon and sausage, by inhibiting the growth of Clostridium botulinum, the microbe that produces the botulism toxin. Sodium nitrite by itself is not a carcinogen, but it commonly combines with amines in protein-rich foods to form the cancer-inducing agent nitrosamine. Strict regulation of nitrosamine levels in cured meats, as well as the required addition of antioxidants, helps mitigate the carcinogenic effect of sodium nitrite in these foods, states Dr. Richard Scanlan of Oregon State University’s Linus Pauling Institute. However, minimize your exposure to dangerous nitrosamines by limiting your intake of foods containing sodium nitrite. When you choose to consume cured meats, eat them with foods containing the antioxidants vitamin C or vitamin E to help reduce the formation of nitrosamines in your body.
Cyanide is an often-lethal, quick-acting poison. In your body, cyanide binds to iron molecules in the enzymes responsible for oxygen transport in your cells, essentially starving your cells for oxygen. Sodium nitrite, when injected intravenously along with sodium thiosulfate, converts hemoglobin to methemoglobin, which in turn tightly binds to the cyanide. This binding pulls the cyanide away from the iron molecules, allowing your cells’ oxygen transport to continue as normal, according to the New York State Department of Health. While sodium nitrite is a standard antidote to cyanide poisoning, an excessive dose of sodium nitrite may cause overproduction of methemoglobin, further decreasing oxygen transport in your cells. Therefore, health care providers must carefully monitor sodium nitrite treatment for cyanide poisoning.