When you’re pregnant, you’re eating for two in a very real sense. Substances you ingest -- both good and bad -- can pass through the placenta to your baby. Sodium nitrite, a preservative found in cured, smoked and processed meats such as hot dogs, ham and bacon, can form potentially harmful substances called nitrosamines, known carcinogens in animals. The amount of nitrites found in processed foods today is considered safe for pregnant women, according to registered dietitian Maria Pari-Keener, M.S.
Sodium nitrite is added to meats to retard spoiling and prevent botulism, a potentially fatal infection. Sodium nitrite also imparts the pink color to hot dogs, sausages and other processed meat and preserves flavors. Sodium nitrite is rated by the United States Food and Drug Administration as Generally Recognized as Safe, or GRAS. The U.S. Department of Agriculture, or USDA, requires manufacturers to add vitamin C in the form of ascorbic acid or sodium erythrobate to foods containing sodium nitrite because vitamin C decreases the formation of nitrosamine.
Nitrosamines form in the highest numbers when foods containing nitrites are cooked at very high heat. Very well-cooked fired bacon is the most likely source of nitrosamines; cooking bacon for four minutes at 400 degrees F increases the amount of nitrosamines formed from 10 to 17 parts per billion, according to Richard Epley, Ph.D., of the University of Minnesota Extension Animal Science division. Bacon is subject to testing for nitrosamines by the USDA.
Studies on the effects of foods containing sodium nitrites have produced mixed results. Some studies, such as a study conducted reported in the April 2001 issue of “Public Health Nutrition,” have shown a two to threefold increase in childhood brain tumors in offspring whose mothers consumed 3 mg of nitrites per day from cured meats. However, researchers from John Cochrane VA Medical Center reported in the 2010 “Journal of Environmental Pathology, Toxicology and Oncology” that the association is questionable because it relies on memory of consumed foods, but it needs further investigation because of the biological plausibility of the connection.
It’s not necessary to eat cured foods that contain nitrites, such as hot dogs, cured ham or bacon while you’re pregnant even though they're considered safe. Limiting exposure by eating these foods infrequently limits your exposure to sodium nitrite. Although the amount of nitrites in these foods has decreased in recent years, it’s better to avoid them because of their high sodium and fat content, nutritionist Sue Gilbert reports. Cooking bacon lightly rather than making it crisp or cooking it in the microwave rather than frying it also decreases the risk of nitrosamine formation. Avoid frying foods that contain sodium nitrite if you eat them while pregnant.
- Parents.com; Nitrates During Pregnancy; Maria Pari-Keener, M.S., R.D.
- "Public Health Nutrition;" Maternal Cured Meat Consumption During Pregnancy and Risk of Paediatric Brain Tumour in Offspring: Potentially Harmful Levels of Intake; J. Pogoda, et al.; April 2001
- “Journal of Environmental Pathology,Toxicology and Oncology;” Maternal Intake of N-Nitroso Compounds from Cured Meat and the Risk of Pediatric Brain Tumors: a Review; M. Huncharek; 2010
- iVillage; Nitrate Consumption During Pregnancy; Sue Gilbert; January 1999