Nitrates and Nitrites: Synthetic and Naturally-Occurring Chemical Compounds Added to Processed Meats
Written by Kathryn West; Edited by Nicki Steinberger, Ph.D.
Originally published by A Voice For Choice Advocacy on December 7, 2023.
EDITOR’S SUMMARY: It doesn’t matter whether you’re in the “yes bacon” camp, or on the “no way, bacon go away” team. If you or those you care about eat processed meats—turkey, salami, chicken, hot dogs, or beef jerky, etc.,—cured or not—knowing the role that nitrates and nitrites play may be worth your time and consideration. It’s easy to be fooled by Big Food industry marketing, and important to know that seeing “uncured,” “no nitrites,” or “no nitrates” printed on packages doesn’t tell the whole story.
The terms “nitrites and nitrates” may seem familiar to you, as visions of bacon, hot dogs, and lunch meat packages from the grocery store shelf swoop through your mind. What are they, and what do they do? At their most basic levels, nitrites and nitrates are two nitrogen compounds needed by plants, animals, and humans to survive. At a chemical level, both nitrites and nitrates contain nitrogen and oxygen atoms. The difference between the two is that nitrites have one nitrogen and two oxygen atoms (NO2), while nitrates have one nitrogen and three oxygen atoms (NO3).
Besides human bodies, nitrites and nitrates can be found in soil, water, air, and plants. It's all part of the earth’s nitrogen cycle. In their natural state, they’re stable and unlikely to change or cause harm. Nitrates are vasodilators. Vasodilate means to widen the blood vessels, leading to improved oxygen-rich blood flowing to your heart and other organs.
When you eat foods containing nitrites or nitrates, they may convert into a related molecular form. For example, nitrates in vegetables can convert into nitric oxide in the body. Nitric oxide dilates blood vessels, which can reduce blood pressure. Furthermore, reducing elevated blood pressure reduces your risk of cardiovascular events.
Since some plants have nitrates, it may improve your blood flow if you eat them. The next time you make a smoothie, for example, try adding beetroot powder, which is high in nitrates. Keep your consumption to a cup or less per day, however, as too much may increase your nitrate intake above an acceptable daily level. A majority of nitrates are found in vegetables, and although levels vary greatly, leafy greens, especially arugula and spinach, contain some of the highest amounts.
“Beet is linked to the improvement of a variety of conditions, especially for anemia. While there are no official guidelines on recommended daily intake, a cup of beet juice a day is typically harmless. According to a study, daily intake of 8.4 ounces of juice lowered both systolic and diastolic blood pressure.”
What ‘Trates and ‘Trites Are Known For
Watch out: In the food industry, nitrites/nitrates are used for preservation (hence why you may have seen food brands claiming “no nitrites”). Nitrites (sodium nitrite and potassium nitrite) and nitrates (sodium nitrate and potassium nitrate) have been authorized to be used as food additives, and are commonly used in meat products to keep them fresh.
This is part of a process called “curing”—adding a combination of salt, sugar, and nitrites/nitrates to meats, for the purpose of preservation, enticing flavor, and enhancing color. Take ham, for example. Ever notice how long it can sit in the fridge? And its signature salty flavor? This is a result of curing, and you have to admit … a gray slice of ham isn’t as appealing as its signature pink look.
Besides ham, other meat products with added nitrites/nitrates include bacon, sausage, hot dogs, and beef jerky, as well as deli meats such as chicken, roast beef, turkey, and salami. Adding the salts of nitrites and nitrates to curing meat also hinders the growth of harmful bacteria toxins that can cause botulism.
Studies have suggested that while eating foods rich in natural nitrates can be beneficial to the body, eating processed meats high in added nitrates/nitrites can cause health risks, including cancer. The difference between consuming naturally-rich nitrate foods and synthetically-added nitrite/nitrate food products lies in how nitrites and nitrates in food get converted into other molecules in your body.
It’s actually sodium nitrite—not nitrate—that’s linked to cancer. Cancer risk is increased when sodium nitrites react with other molecules in your body. It’s not the nitrates and nitrites themselves that cause health issues, rather, it’s the form they are converted into that increases the danger.
As part of the process of digesting the protein, sodium nitrite reacts with fragmented bits of amino acids. Consequently, this forms molecules called N-nitroso compounds (NOCs), or nitrosamines. And NOCs have been shown to cause cancer.
From “Why nitrates and nitrites in processed meats are harmful – but those in vegetables aren’t”:
“Cancer-causing NOCs can form either during the preparation of nitrite-containing processed meats or during their digestion in the gut. This is because both the preparation and digestion of processed meats generate plenty of protein fragments for the nitrites to react with.”
On the other hand, vitamins C and E are considered inhibitors of the NOC forming process. And eating vegetables high in nitrates doesn’t increase cancer risk because, as one researcher put it:
“The nitrite needs to be activated before it can react with protein fragments. This is where a molecule called haem comes in. Haem reacts with nitrites, resulting in a molecule called nitrosylated-haem. It’s this molecule – rather than the nitrite itself – that likely reacts with protein fragments to form NOCs. Haem is abundant in meats – and is actually what gives meat its color. But it’s not naturally present in vegetables. So even nitrate-rich vegetables don’t pose a risk of forming NOCs if there’s no source of haem.”
The conversion to nitrite and further metabolism of nitrogen compounds to nitrosamines has been linked to gastric cancer. From “Dietary intake of polyphenols, nitrate and nitrite and gastric cancer risk in Mexico City,” “High consumption of total nitrite, and nitrate and nitrite from animal sources was associated with an increased risk of GC.”
From “Nitrates/Nitrites in Food—Risk for Nitrosative Stress and Benefits”:
“Due to potential carcinogenic effects, nitrates and nitrites should be limited in the meat industry. However, finding the perfect alternative to nitrates/nitrites in meat processing is very difficult due to its multifunctional nature."
Controversy Over This “Naturally-Occurring” Preservative
A common alternative to synthetic sodium nitrite is celery powder, often used in “naturally cured” or “uncured” meats. While it sounds super-healthy, and may be a step or two above added synthetics, it still has to undergo significant processing, and in turn, does not have to be organic.
Some researchers have concluded that uncured meats made with celery powder and other natural nitrite/nitrate sources aren’t much different than their processed counterparts. From Consumer Reports, “Danger at the Deli,” Joseph Sebranek, Ph.D., Morrison Endowed Chair in meat science at Iowa State University agreed:
“But don't "uncured" cold cuts at least have lower amounts of those compounds? Nope, according to CR's recent tests of 31 deli meats. Products cured with nitrates and nitrites from natural sources had average levels of the chemicals that were similar to those cured with synthetic ones. And it didn't matter what type of meat it was—chicken, ham, roast beef, turkey, or salami.”
Sebranek adds:
“There is a somewhat broad consensus that whether those nitrites are man-made or come from celery or other vegetables, they are virtually indistinguishable to the human body. ‘“There is absolutely no difference in the way we process nitrites,”’ says Sebranek. ‘“It makes no sense how these products are labeled differently.”’
From Jeffrey Sindelar, professor of meat science at the University of Wisconsin, Madison:
‘“Forty or 50 years ago, manufacturers who wanted to process meats without man-made preservatives were largely out of luck. And those who’ve tried to sell truly uncured meats have ended up producing gray products with odd textures and flavors.
“I’m not trying to dumb it down too much here,” he says, “but a truly uncured hot dog is just loose ground meat in a casing.”’
Results from this study are inconclusive: From ScienceDirect, Meat Science, “Potentially probiotic or postbiotic pre-converted nitrite from celery produced by an axenic culture system with probiotic lacticaseibacilli strain”:
“The use of probiotic strains to obtain pre-converted nitrite from celery is a convenient alternative to replace the addition of sodium nitrite in cured meat products. However, further studies should be considered to properly evaluate the metabolism of each strain in a specific matrix. The results of this study demonstrated that the rates related to the nitrite generation and nitrate consumption were not proportional, suggesting the existence of a minimal NiR pool to start the conversion and/or …”
As for the organic/non-organic concern: Celery ranks near the top of the list for the number of chemicals from pesticide contamination. From “11 things it's best to buy organic”:
“When researchers at the EWG analyzed 89,000 produce-pesticide tests to determine the most contaminated fruits and vegetables, celery topped the chart. "In terms of the sheer number of chemicals, it was the worst," says Sonya Lunder, senior analyst at the EWG. Celery stalks are very porous, so they retain the pesticides they're sprayed with - up to 13 of them, according to the EWG analysis.”
From OMRI, whose mission is to support the growth of the organic community: “Nonorganic celery powder is very high in nitrates because conventional celery is produced with synthetic high-nitrogen fertilizers.”
Therefore, it’s imperative to read the list of ingredients in your processed meats (and for that matter, in everything you decide to put in/on your body), rather than settle with the marketing on the front of the package that reads “no nitrites and no antibiotics … ever.” There are brands using organic celery powder, and this is an important distinction to make when choosing your products.
Some would argue that the old-fashioned way of salting and resting meat with no added nitrates is the most logical way to cure meat. Taken from the Guardian, French journalist and author, Guillaume Coudray:
‘“Pure insane crazy madness”’ is how Coudray described the continuing use of nitrates and nitrites in processed meats, in an email to me. The madness, in his view, is that it is possible to make bacon and ham in ways that would be less carcinogenic. The most basic way to cure any meat is to salt it – either with a dry salt rub or a wet brine – and to wait for time to do the rest. Coudray notes that ham and bacon manufacturers claim this old-fashioned way of curing isn’t safe. But the real reason they reject it is cost: it takes much longer for processed meats to develop their flavour this way, which cuts into profits.”
And what about nitrites/nitrates from foods grown with chemical fertilizers? Adding nitrogen to soil can lead to runoff or leakage, resulting in nitrates leaching into the groundwater. Methemoglobinemia, which is the decreased ability of the blood to carry oxygen to tissues, can occur as a result of high-nitrite contamination.
From the Centers for Disease Control and Prevention (CDC), “Methemoglobinemia Attributable to Nitrite Contamination of Potable Water Through Boiler Fluid Additives -- New Jersey, 1992 and 1996”:
“On October 20, 1992, a school nurse contacted the New Jersey Poison Information and Education System regarding the acute onset of illnesses in 49 children in first through fourth grades in one school. All of the children had visited the school nurse within 45 minutes after lunch because of blueness of the lips and fingers. The poison center, after ruling out a possible local stain, suggested that the children be examined at a hospital. When the children were examined, additional complaints included nausea, vomiting, and headache. An emergency department physician, in consultation with the poison center, made the presumptive diagnosis of MetHb on the basis of cyanosis with normal pulse oximetry readings of oxygen saturation >88%. Initial questioning by the poison center did not identify possible sources.”
“The field investigation indicated that the children with MetHb had eaten soup served during the second lunch period. The soup had been prepared from a commercially canned product that was taken directly from the can and heated before being served. To provide second servings, the soup was diluted with a 1:1 ratio of water obtained from hot and cold water taps in the school kitchen. Analysis of the leftover diluted soup detected nitrite levels of 459 parts per million (ppm). Samples of the original undiluted soup contained a nitrite level of 2 ppm.”
Symptoms of methemoglobinemia may include decreased blood pressure, increased heart rate, headaches, abdominal cramps, vomiting, and death. Animal studies showed changes in thyroid function in rats that were fed, or drank high levels of nitrate or nitrite. While many people are not exposed to high enough levels to cause problems, caution remains to minimize your consumption.
From “The truth about nitrates and nitrites”:
“The nutrients that we consume react together in many different ways – which is why nitrates and nitrites can be safe for us in some foods, and may be harmful when they come from others,” read a study published in World Cancer Research Fund International. “However, some advisory bodies now recommend that because of their cancer risk we should eat little, if any, processed meat."
Ideas to Reduce Your Nitrite/Nitrate Intake
Avoid unnecessary amounts of nitrites/nitrates in commercially-grown fruits and vegetables by eating organic whenever possible. It’s common sense when you consider that nitrate levels are generally higher in conventionally-grown crops, because of high mineral nitrogen inputs.
Limit processed meat consumption. Kick around the idea of substituting your deli meat sandwich with grass-fed/finished ground beef or steak, portobello mushroom, vegetables, mashed beans, or a protein that hasn’t been cured, or potentially compromised with synthetic or naturally-occurring nitrites/nitrates.
As stated, sodium nitrite consumption comes with a cancer risk. As with a host of things, moderation can be helpful. According to the Harvard T.H. Chan School of Public Health: “... eating a small amount of processed meat occasionally, such as once or twice a month, is unlikely to significantly harm health.” To each their own, and of course the choice is yours to define “significantly” for yourself.
If you do consume cured meats, or for that matter, uncured with naturally-occurring nitrites/nitrates, source them from a sustainable, preferably local farm, and make sure the sourced celery powder is organic. The more traditional (vs. conventional) the method, the less chemicals used. It’s the chemicals from modern cured meats, containing nitrosamines, that stand out as most harmful.
Also consider adding half a glass of freshly-squeezed orange juice (if you don’t experience type 2 diabetes, prediabetes, or metabolic syndrome) to your meal, or other sources of vitamin C, such as kiwis, acerola cherries, or cantaloupe, to ward off harmful effects of N-nitroso compounds (NOCs), or nitrosamines.
Fill up on naturally-rich, unprocessed, organic nitrite/nitrate foods. This could mean incorporating bok choy or carrots into your salad, stew, or stir-fry. In addition to leafy greens, other foods include garlic, watermelon, rhubarb, pomegranates, and dark chocolate. Stay open: Curiosity and creativity may lead you to discover new heights in enhanced nutrition, as you experiment with rich, colorful foods, and eliminate what no longer makes sense.
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