Sodium nitrite is a food preservative that also gives cured and processed meats, such as ham and hot dogs, their characteristic pinkish color. Many vegetables, including spinach, celery, beets and cabbage, naturally contain large amounts of nitrite. Most people get 90 percent of their nitrite intake from vegetables and 10 percent from cured meats, according to Richard Epley of the University of Minnesota Extension. Sodium nitrite is also used to treat cyanide poisoning. Sodium nitrite can cause allergic reactions in some individuals.
Sodium nitrite injections are used as an emergency treatment for cyanide poisoning and may also have benefit in treating sickle cell anemia. In some people, sodium nitrite injection could trigger allergic reactions, development of hives, runny nose or asthma. Signs of allergic reaction can include skin rash or hives, difficulty breathing, swelling of the face, especially around the mouth or eyes, or swelling in the throat. Rapid heartbeat, dizziness, nausea, abdominal pain or cyanosis, a bluish tinge to the extremities or face that indicates a lack of oxygen, can also occur. Loss of consciousness or collapse is a sign of a severe allergic reaction called anaphylaxis. Seek immediate medical attention if severe allergic symptoms appear after injection of sodium nitrite.
Allergic reactions can occur from sodium nitrite in foods. Sodium nitrite is added to meat both to makes it look more appealing and to delay the growth of bacteria that cause serious illnesses, such as botulism. Sodium nitrite gives cured meat its characteristic flavor and retards spoilage, allowing it to keep longer. A number of cured or processed meats, including sausage, bacon, hot dogs and ham, contain sodium nitrite.
Sodium nitrite ingestion may have long-term side effects, including an increased risk of developing cancer. The cancer risk of sodium nitrite comes not from the chemical itself but from the formation of nitrosamines during the cooking process. Nitrosamines are formed from a reaction between breakdown products from animal proteins, called amines and nitrites. Cooking foods, particularly bacon, over very high temperatures can cause nitrosamine formation. Adding ascorbic acid, or vitamin C, or erythorbic acid to the meat cure decreases formation of nitrosamines. Most manufacturers now add erythorbic acid to their products. Nitrosamines are known carcinogens in animals and may cause cancer in people under some conditions.
Although nitrites are classified as “generally regarded as safe” by the U.S. Food and Drug Administration, the long-term effects of heavy exposure to sodium nitrite has not been established in humans. Do not overcook cured meats or fry them at high temperatures. Cooking bacon in a microwave oven reduces nitrosamine formation.