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Nitrates and Nitrites

Nitrates and nitrites are compounds containing a nitrogen atom joined to oxygen atoms. Nitrate is represented as NO3 while nitrite is NO2. The presence of nitrates occurs naturally and it is contained in many substances.

Where are they found?
Nitrates are found in soil, water, plant materials, fertilizers, air and cured meats. Nitrate is formed from the natural conversion of nitrogen to nitrate via bacteria. This material is then absorbed by plants through the soil and stored in tissue. Animals ingesting plant matter use the nitrate to produce proteins.

The nitrogen cycle (converting nitrogen to nitrate to nitrite and back to nitrogen again) is a natural cycle that keeps excessive amounts of nitrates or nitrites from accumulating in the environment. Of course, humans have been greatly affecting this balance in the environment. The major source of increased environmental nitrate concentrations is due to agriculture. This comes from the levels of fertilizers used as well as from livestock and poultry farming, the latter two contributing to the excess through the large volume of nitrate-rich manure.

How are they used?
Nitrates are primarily used in the production of fertilizers. However, they are also used in making glass and explosives. The manufacturing of nitrites is mainly to serve as a food preservative. The enhancement of coloration and shelf life of processed meats is accomplished by the use of nitrates and nitrites. These additives also act as a means of preventing botulism.

Physiological effects
In most healthy adults, nitrates and nitrites are rapidly absorbed by the gastrointestinal tract and excreted by the kidneys. One of the major health effects of nitrate/nitrite consumption is the development of methaemoglobinaemia, a clinical condition arising from the interaction of nitrites and hemoglobin in the blood. This interaction, a result from an oxidation of the body’s divalent iron to trivalent iron, forms methemoglobin. Methemoglobin inhibits oxygen binding which in turn lowers the blood’s ability to transport oxygen to the lungs and therefore the rest of the body.

The threat of methaemoglobinaemia is highest among very young children. Because the conditions of the stomach can play a large role in the conversion of nitrate to nitrite, infants are more susceptible due to a higher pH of gastric fluid. This condition is not the only potential threat of nitrate or nitrite ingestion.

There are two other health concerns that are worth mentioning, but please keep in mind that further research in still needed in both of these areas. The first topic is Chronic Obstructive Pulmonary Disease (COPD) and the second is stomach cancer.

Recently 7,352 adults participated in the Third National Health and Nutrition Examination Survey. The study showed evidence to suggest that consuming 14 or more portions of cured meat per month may increase the risk of COPD. The study looked at rating of forced expiratory volume (the volume of air that can be forced out taking a deep breath, an important measure of pulmonary function) and forced vital capacity (the total amount of air that you can forcibly blow out after full inspiration). There were no significant indicators showing a change in FVC. In evaluating FEV, researchers did see evidence of significant changes according to pre-trial criteria for levels outside the normal deviance.

These research findings are looked at with great interest because COPD is a high cause of death in both the U.S. and U.K. Anything that may help in finding out more about the causes of COPD are looked at with promise. While this study reveals some interesting information, there is need to focus a little more on the quantitative amounts of nitrites to form a baseline for comparison.

Lastly, I would like to mention briefly the correlation between nitrates and stomach cancer. The process of changing nitrate to nitrite in the gastrointestinal tract can also lead to a change from nitrite to N-nitroso compounds, which have been found to be carcinogenic in test animals. The evidence relating to human consumption, on the other hand, is still inconclusive and highly debated.

Though it is still questionable as to how much nitrates and nitrites, if any, may cause stomach cancer, it has still been advised to limit the intake of these preservatives, particularly in infants as stated earlier when discussing methaemoglobinaemia. Nitrate/nitrite poisoning fatalities have all been in infants.

Take caution
So just be wary of what you buy, of how much you eat and avoid high heat when cooking cured meats as this can increase N-nitroso compounds.

At the Co-op
Okay, I can give a little rundown on the nitrate-free stuff we carry. For starters, the entire line of Applegate Farms is nitrate/nitrite-free which encompasses the chicken and turkey sausages, pepperoni, genoa salami and all the other lunch meats we carry. Their frozen items (turkey bacon, chicken pot-pie, chicken franks, and turkey burgers) are also nitrate/nitrite-free. Willow Creek’s frozen sausages (Kielbasa, Andouille, Brats, Sweet Italian links) are also nitrate/nitrite-free as are any of their ground products. For bacon we offer two choices of nitrate/nitrite-free, Applegate’s Sunday Bacon and Beelor’s Uncured Bacon (frozen).

For additional frozen items we also have Shelton’s meats which are all uncured, nitrate/nitrite-free products and include a ground turkey, turkey franks and a chicken frank.