Potassium nitrate, chemically known as KNO3 and commonly called saltpeter, is a natural source of nitrogen. The properties of potassium nitrate make it useful in a variety of applications, including as a fertilizer, propellant and food preservative. The safety of potassium nitrate depends on its intended use and the amount ingested.
Toothpaste
In 2003, the American Academy of Cosmetic Dentistry reported that the use of tooth whitening, or bleaching, increased by 300 percent in the preceding five years. As more and more people look to brighten their smiles, more and more companies provide over-the-counter tooth whitening products for use at home. Many types of toothpaste contain carbamide peroxide to make teeth whiter, but this substance can also make teeth sensitive to hot or cold foods and beverages. Manufacturers add potassium nitrate along with fluoride to toothpaste to help reduce tooth sensitivity side effects. Studies, such as the one published in the March 2011 issue of "The Open Dentistry Journal," find potassium nitrate to be a safe and effective ingredient.
Meat Preservative
Historically, food manufacturers used potassium nitrate to salt or cure meats. As a salt, potassium nitrate inhibits the growth of microorganisms. Treating meat, either using a dry rub or soaking in a brine solution with salt, nitrate and sugar, preserves it and enhances the flavor and color. In the early 1800s, people discovered that using saltpeter to cure meat turned the meat pink rather than gray and inhibited the growth of clostridium botulinum, which other salt mixtures failed to do. Commercially preserved meat contains safe amounts of potassium nitrate, but due to the risk of toxicity, you can no longer purchase it to use for curing meat at home.
Cancer Risk
In the 1960s and 1970s, a debate ignited about the use of nitrates and nitrites in meat. The fear centered on the possible presence of nitrosamines, a known cancer-causing agent, in meat cured with nitrates like potassium nitrate. Information released by the American Meat Science Association reveals that the level of nitrosamines in cured meats remains extremely low and that these meats are safe to consume.
Nitrates in Water
The use of fertilizers that contain high concentrations of potassium nitrate can contaminate underground sources of drinking water. Ingesting large quantities of nitrates and nitrites can cause adverse health effects. A study published in the November 2005 issue of "Environmental Health Perspectives" reports that nitrates in drinking water cause birth defects, spontaneous abortions and other reproductive side effects like reduced fertility. This study also recognizes that you must consume high concentrations of nitrates to experience adverse effects, and drinking water fails to contain high concentrations. Chronic exposure to low levels of nitrates in drinking water fails to cause any adverse health effects.
References
- American Academy of Cosmetic Dentistry; Tremendous Growth Seen in Cosmetic Dentistry -- Patients Want Smile Transformations; May 2003
- "The Open Dentistry Journal"; In Vivo Spectrophotographic Assessment of the Tooth Whitening Effectiveness of Nite White; Grobler; March 2011
- American Meat Science Association: Safety of Cured Pork Products
- The University of Georgia -- The National Center for Home Food Preservation: Smoking and Curing
- "Environmental Health Perspectives"; A Review of Nitrates in Drinking Water; Manassaram; March 2006
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