Nitrates are salt compounds that naturally occur in all vegetables and fruit. Commercially, they are commonly used for curing food such as salami, bacon and hot dogs. With the help of bacteria, nitrates are chemically converted into nitrites, which have slightly different properties. High consumption of both nitrates and nitrites has been linked to various issues, including cancer, although scientific research on their health implications is not clear.
Nitrate is a type of salt derived from nitric acid and usually sodium. Sodium nitrate naturally occurs in all fruit, veggies and grains -- to varying degrees -- because it’s present in the soil. Nitrates are absorbed by all plants and used as a source of nitrogen. Nitrate levels are typically lowest in fruit and highest in veggies, especially carrots, celery, radishes, beets, lettuce and spinach. Artificially produced nitrates are used in industrial fertilizers -- to stimulate plant growth -- and for preserving and curing meats because they deter the growth of microorganisms.
Nitrites are derived from nitrates. Plants naturally convert nitrates into nitrites and so does your body. Sodium nitrite is a good antibacterial and especially effective at preventing the growth of Clostridium botulinum -- the bacteria that causes a potentially fatal paralytic illness called botulism. The conversion of nitrates into nitrites begins in your mouth and culminates in your stomach. Depending on various factors such as stomach pH, body temperature and the presence of antioxidants, sodium nitrite is either converted into nitric oxide or compounds called nitrosamines. Nitric oxide helps blood vessels relax, lowers blood pressure and displays mild anti-inflammatory activity. In contrast, nitrosamines are considered undesirable because they are potentially carcinogenic and damaging to tissues.
Scientific research beginning in the 1950s concluded that nitrosamines greatly increase the risk of cancer in a variety of animals including rats and cows. However, further research since that time is either contradictory or unclear, so the National Academy of Sciences, American Cancer Society and National Research Council state that there's no evidence of increased risk of cancer from consuming nitrites. This apparent contradiction may be related to the presence of antioxidants such as vitamins C and E. Natural plant-based sources of nitrates and nitrites contain vitamins C and E, which inhibit the formation of nitrosamines in the stomach. Artificial sources once did not contain antioxidants, but manufacturers of cured meats are now required to add vitamin C -- also called ascorbic acid -- to limit the conversion of nitrites to nitrosamines. However, the nitric oxide produced from nitrites can still trigger migraine headaches in sensitive individuals due to its dilatory effect on blood vessels.
Fresh fruit and veggies high in nitrates and nitrites are not linked to serious health issues because they contain vitamin C and other antioxidants that inhibit the conversion to nitrosamines. Cured meats are likely safer to eat now than they were many years ago because artificial nitrate/nitrite preservatives must contain vitamin C. Some cured meats contain natural nitrate/nitrite preservatives -- usually derived from celery juice or powder -- but it’s not conclusively known if they are healthier options.
- The American Journal of Clinical Nutrition: Food Sources of Nitrates and Nitrites: The Physiologic Context for Potential Health Benefits
- Applied Microbiology: Effect of Sodium Nitrite on Toxin Production by Clostridium botulinum in Bacon
- Oregon State University: Linus Pauling Institute: Nitrosamines and Cancer
- Meat Science: Cured Meat Products Without Direct Addition of Nitrate or Nitrite: What are the Issues?
- Jupiterimages/Comstock/Getty Images
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.