What are nitrates and nitrites?

Dr. MacDonald: “Nitrogen is an essential element for all forms of life. The nitrogen cycle wherein nitrogen is used and released involves the formation of nitrates and nitrites by plants, animals and microorganisms.

“There are several forms of nitrates in nature. These three are naturally occurring:

• Nitric oxide (NO) is a gas and is created in the atmosphere by lightning and radiation, it is carried into the soil by rain. Humans and most animals also utilize nitric oxide as a regulatory molecule. For example, NO is essential for proper functioning of the cells that line arteries and veins. In fact, nitroglycerin, a form of nitrates, has been used for many decades as a medication to treat angina because it causes relaxation of blood vessels.
• Nitrite (NO2) is formed by microorganisms in the soil as they breakdown animal matter and is widely found in plant foods and drinking water. This is the major form that would be found in our diets.
• Nitrate (NO3) is present in natural mineral deposits such as saltpeter.

“In our bodies, nitrate that is consumed in foods or water can be converted to nitrites by oral bacteria which are then absorbed and used to make nitric oxide. Nitrates are efficiently absorbed from the stomach and intestines into the blood, but the majority is excreted through the urine. A balance of nitrate levels is maintained by this system.”

Dr. MacDonald:

“Nitrates are used primarily in the curing of meats to maintain the color of red meats and to block the growth of the deadly bacteria Clostridium botulinum that can thrive in oxygen-deprived environments such as occur in cured meats.”

“The amount of nitrates added to cured meats is magnitudes less the amounts of nitrates we consume in plant foods. The acceptable daily intake of nitrate is in the range of about 260 mg for a 150-pound adult. One hot dog has about 10 mg of nitrates, so consuming even three hot dogs will not come close to the amount that would be considered high. In fact, eating a cup of spinach provides nearly 140 mg of nitrates, which is much higher than the amount in three hot dogs.”
Plants often contain more nitrates than meats do.

“Natural nitrates are really no different chemically than the nitrates used in food processing. The body sees them exactly the same. Because plants are rich sources of nitrates, some food processors have begun using celery juice as a way to ‘naturally cure’ meats.

“Cured meats have been a target for health concerns recently. The evidence suggests that in cultures where the diets include regular (daily) consumption of meats that have been cured, smoked, and salted have higher risks of stomach cancer. It is difficult to separate the exact cause and effect of this relationship because of the many variables. It is known that smoked foods contain a variety of potential cancer-causing compounds, and high salt intakes cause damage to the stomach lining that may be related to cancer progression. There is no evidence that nitrate-cured meats, in particular, increase the risk of cancer in the US. Given the small amount of nitrates that are contributed from cured meats, in comparison to vegetables and drinking water, is seems unreasonable to be concerned about eating foods that are preserved with nitrates.”

Read more form , Dr. Ruth MacDonald, chair of the Department of Food Science and Human Nutrition at Iowa State University, at Best Food facts.org