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Facts About Sodium Nitrate and Sodium Nitrite

Are the Health Concerns About Nitrates Overblown?

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Nitrates - Sodium Nitrate - Sodium Nitrite Photo © Mike Johnson

Facts About Sodium Nitrate

Nitrates and nitrites are chemical compounds commonly used in making cured meat products like bacon and hot dogs. A lot of ink has been spilled discussing the idea that nitrates and nitrites are bad for you, and food manufacturers have introduced all kinds of supposedly "nitrate-free" products to meet the resulting consumer demand.

But what you may not know is that not only are the fears over nitrates completely overblown, but these "nitrate-free" products can actually contain many times more nitrates than conventional products.

Not only that, but a truly nitrate-free hot dog would be much more likely to make you sick than a conventional one.

Nitrates and Preserving Foods

Nitrates are used in curing, which is a broad category of techniques for preserving foods, mainly meat and fish, that involves the use of salt, sugar, or some form of dehydration. In each case, the goal is to make the food unattractive to the bacteria that cause food spoilage. This works because bacteria are tiny organisms that require, among other things, moisture, oxygen and food. Take away one of these things and they die.

There's an exception to this rule, and it involves a type of bacteria that can only live in an oxygen-free environment. We'll talk about that in a moment.

Salt as a Food Preservative

One of the earliest methods for curing food involved the use of salt. Salt prevents food spoilage through a process known as osmosis, whereby it basically sucks the moisture out of the bacteria's bodies, killing them by dehydration.

Sodium nitrate is a type of salt that happens to be a particularly effective food preservative. A naturally occurring mineral, sodium nitrate is present in all kinds of vegetables (root veggies like carrots as well as leafy greens like celery and spinach) along with all sorts of fruits and grains. Basically, anything that grows from the ground draws sodium nitrate out of the soil.

If this seems strange, remember that the word nitrate refers to a compound made of nitrogen, which is the single biggest component of our atmosphere. Every time you take a breath, you're breathing 78 percent nitrogen. The soil itself is loaded with the stuff.

Nitrates and Nitrites

One of the things that happens when sodium nitrate is used as a curing agent is that the sodium nitrate is converted to sodium nitrite. It's sodium nitrite that actually possesses the antimicrobial properties that make it a good preservative. Interestingly, the sodium nitrate that we consume through fruits, vegetables and grains is also converted to sodium nitrite by our digestive process. In other words, when we eat fruits, vegetables or grains, our bodies produce sodium nitrite.

Nitrites and Cancer

Several decades ago, some researchers raised the possibility that nitrites could be linked to cancer in laboratory rats. This suggestion received a lot of media attention. What received less media attention, however, was when further research revealed that they were wrong. Indeed, the National Academy of Sciences, the American Cancer Society and the National Research Council all agree that there's no proof of cancer risk from consuming sodium nitrite.

Nitrate-Free Products

So what about all those supposedly "nitrate-free" hot dogs, bacon and other so-called "uncured" products? Since completely uncured hot dogs are not palatable to consumers, it's very rare indeed to find a product that is totally nitrate-free. Instead, manufacturers make claims such as "no nitrates added."

The reality is that companies that make nitrate-free hot dogs have to use something to substitute for the sodium nitrate. Celery juice is a popular choice. And guess what celery juice contains lots of? Sodium nitrate. And guess what that sodium nitrate turns into when you eat it? Sodium nitrite!

As we said earlier, celery is a natural source of sodium nitrate. (Notice that no one is currently claiming that celery causes cancer or that people should reduce their intake of celery.) But by adding celery juice to their hot dogs, manufacturers can make products loaded with sodium nitrate while legally being able to claim "no added nitrates." Because all the nitrates are in the celery juice. As a matter of fact, these supposedly "natural" or "organic" products sometimes contain twice as much sodium nitrate, even up to a whopping ten times as much sodium nitrate, as conventional products.

Nitrites and Botulism

So nitrates and nitrites are both harmless and ubiquitous. But is it really possible that eating nitrate-free meats could actually be more dangerous than eating meats that do contain sodium nitrate? The answer is yes.

One special property of sodium nitrite is that it prevents the growth of Clostridium botulinum. These bacteria produce the botulism toxin, one of the most lethal substances known, which causes a paralytic illness that can lead to respiratory failure.

The botulism bacteria is peculiar bug because unlike most microbes, it actually requires an oxygen-free environment to live. Once it hits the air, it dies. So it tends to appear in canned foods, vacuum-packed foods, garlic stored in oil and improperly cured meats. It just so happens that sodium nitrite is especially effective at preventing the growth of Clostridium botulinum.

Conclusions About Nitrates and Nitrites

Given that sodium nitrate occurs naturally in foods like spinach, carrots and celery, as well as the fact that nitrite has never been shown to cause cancer, all the fuss about nitrates and nitrites might seem like typical media-driven hysteria. Moreover, the supposedly "natural" or "organic" versions of these products can contain many times more sodium nitrate than their conventional counterparts. But when you consider the increased likelihood of contracting botulism, it's actually the nitrate-free products that present the real health risk.
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