Savvy Consumer: How much do you really know about nitrates?
August 26, 2015
In the quest to make responsible food choices, many people may rely on a product’s marketing claims to guide their purchases. Unfortunately sometimes these claims can be more confusing than helpful!
Picture yourself in the supermarket shopping for your next BBQ. You take a look at a package of hot dogs that may say in large, bold type “Uncured,” “All Natural,” or “No Nitrates or Nitrites Added.” This sounds great until you read the fine print that says “except for those naturally occurring in celery juice.” Now you may just be confused. What’s the difference and is the “natural” product really the healthier choice? And what’s all the fuss about nitrates/nitrites to begin with?
What are nitrate and nitrite?
Nitrate is a naturally occurring chemical that produces the metabolite nitrite. While we mostly associate nitrates and nitrites with cured meats, in reality, over 80% of the nitrates we consume come from vegetables. These dietary nitrates are absorbed into our blood and either excreted or recycled into our saliva. Through this recycling process, some of this nitrate is converted to nitrite in the mouth which is why our own saliva accounts for over 90% of our nitrite intake.(1) Bottom line: most nitrates in our diets are from vegetables and most of the nitrite we consume is from our own saliva. Now that we covered that, let’s get back to the hot dogs.
Nitrite use in cured meats
For centuries, salt has been used to preserve meat and in the Middle Ages, people discovered that “saltpeter” or potassium nitrate preserved the color and flavor of meat. Later in the 1900s chemists uncovered that nitrite (formed from the nitrate) was the actual active component with the desirable antioxidant activities.(2)
This discovery led to the practice of adding the isolated nitrite (in the form of sodium nitrite) directly to meat products as a preservative. Scientists also discovered that in addition to preserving color and flavor, nitrite inhibited the growth of harmful anaerobic bacteria such as clostridium botulinum, an important benefit for food safety. With the regulated use of sodium nitrite, botulism incidents have decreased dramatically.(1)
Because excessive amounts of nitrite are toxic, the use of curing salts like sodium nitrite is tightly regulated. Synthetic curing salts are composed of exactly 93.75% sodium and 6.25% nitrite and the amount of nitrite in the finished product cannot exceed 200 parts per million(.02%).(2,4) By these standards, the amount of nitrite that can potentially be ingested from the curing salt in a cured meat product is actually very small.
In addition to the potential toxicity of nitrite itself, under certain conditions, nitrites can produce yet another compound called nitrosamine, which form when nitrites interact with the amino acids from a protein source (like meat) in an acidic environment (such as your stomach) or during high heat cooking methods (such as deep frying). While nitrosamines may be carcinogenic in large quantities, there is limited evidence that dietary nitrite, when consumed as part of a balanced diet, significantly increases the risk for developing cancer.(3) Perhaps this is because of the antioxidant effects of vegetables which may neutralize the impact of nitrates and nitrites. Additionally, ascorbic acid (Vitamin C) is often added to processed meats to counteract the potential effects of sodium nitrite. And lest you think you should eat less vegetables to reduce your nitrate intake, vegetables don’t contain the protein of cured meat products so the likelihood of nitrosamine formation is much lower and the beneficial nutrients in vegetables far outweigh any potential risks of nitrosamine formation.
Are "naturally cured" meats really better?
Since nitrates are present in vegetables, ingredients like celery juice or powder can be added to meats to supply the nitrites needed to cure the meat. While this sounds like a more natural process than adding curing salts, there are some issues to keep in mind.
According to charcutier Jay Denham by using sodium nitrite rather than a naturally derived nitrate, he is able to use the minimum amount of nitrite that is necessary for food safety while maintaining a consistent product and preserving the intrinsic taste of the meat itself. Conversely, he states, “when using naturally derived nitrates there is no consistent way to measure the amount of nitrite that will be produced so it requires the addition of larger amounts of these ingredients (i.e celery powder) which not only can result in larger amounts of nitrite in the finished product but can also impart an undesirable flavor.”
In contrast to the use of synthetic sodium nitrite, there are no regulations for the amount of allowable naturally occurring nitrate such as those derived from celery powder. As such, there is potential for a wide range of the amount of nitrite found in naturally-cured products. This is not only a challenge for ensuring food safety but in some cases the amount of nitrite formed from a natural product can exceed the amount that would be in a conventional product that was made using a controlled amount.
So what's the takeaway?
Regardless of the curing process, a diet high in cured meats and low in fruits and vegetables is reason for concern, not only because of the consumption of nitrite from protein-rich products cooked at high temperatures, but also because cured meats are typically high in saturated fat and sodium. “Nitrate-free” products have a health halo but still may contain high amounts of sodium or saturated fat. And, if you read the fine print, contain inconsistent amounts of naturally-occurring nitrates which our bodies treat in the same way as the synthetic variety.
Our advice is to stay mindful of the “health halos” associated with the natural varieties of these products and don’t let the claims about the source of nitrates be the only factor in your evaluation of a product. And of course, the healthiest choice is to keep eating your fruits and vegetables and limit your intake of processed meat overall, regardless of where the nitrites are coming from.
Still looking for more information? Check out our infographic on this topic.
1) Douglas L. Archer, “Evidence that Ingested Nitrate and Nitrite Are Beneficial to Health,” Journal of Food Protection, Vol 65, No. 5, 2002, pp. 872-875.
2) McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York, NY: Scribner Publishing; 2004.
3) Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. 2007, World Cancer Research Fund, American Institute for Cancer Research.: Washington, DC.
4) Sebranek JG and Bachus JN, "Cured meat products without direct addition of nitrate or nitrite: what are the issues?," Meat Science, Vol 77, No. 1, 2007, pp. 136-147.
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