If you take a look at the ingredient list on the back of a pack of bacon, jerky or hot dogs, you'll probably spot sodium nitrate. Simply put, sodium nitrate is a type of salt often added to meat products as a preservative. While excess salt comes with its own health risks, sodium nitrate, specifically, is tied to cancer.
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How Nitrates in Food Are Linked to Cancer
An October 2015 report by the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), deems processed meats (including hot dogs, sausages, corned beef, jerky and canned meats) carcinogenic to humans. In fact, the IARC classifies processed meats as a Group 1 carcinogen — the same group as tobacco smoking and asbestos.
So, what makes sodium nitrates so harmful? The process involved in making these meats (adding in nitrates as well as nitrites, another type of preservative) is linked to colorectal cancer and stomach cancer, per the Harvard T. H. Chan School of Public Health.
Even though the IARC classifies processed meats at the same level as smoking, smoking has a much higher carcinogenic risk factor. So, eating processed meats isn't as bad as smoking cigarettes; however, your bacon sandwich comes with some risk.
But it's not just about what's in processed meats — it's also about how they're cooked.
"When nitrates are exposed to high heat, especially in the presence of proteins [like those in meat], they can turn into compounds called nitrosamines," says Bonnie Taub-Dix, RDN, creator of BetterThanDieting.com and author of Read It Before You Eat It: Taking You from Label to Table. "It's those nitrosamines that could be dangerous or potentially carcinogenic and grilling or barbecuing processed meats can increase the potential harm from the nitrates in these products."
You should also note that cooking all types of meats, not just processed meats, at a high temperature can produce nitrosamines, per a September 2015 study in Toxicological Research. The IARC classifies red meats as probably carcinogenic to humans — so, not as severe as processed meats but still a potential health risk.
Read more: 5 Reasons People Become Vegetarian
Where Else Can You Find Sodium Nitrate?
As well as acting as a food additive, sodium nitrate can be found in pesticides, manufacturing processes and paints, according to the National Center for Biotechnology Information.
It may surprise you to learn that sodium nitrate can also be used in a medical context. Studies have found that ingesting oral sodium nitrate lowers blood pressure, according to a July 2016 article published in the Journal of the American Heart Association (JAHA). Researchers explain that, in certain circumstances and doses, sodium nitrate has similar health benefits to the natural nitrates found in leafy and root vegetables — in this case, improved blood pressure.
And another JAHA study, published in September 2017, found that sodium nitrate helped patients with chronic chest pain exercise more when it was taken in addition to their normal medications.
In short: Oral sodium nitrate might be able to improve cardiovascular health when used with a physician's direction. However, don't try this at home.
The Bottom Line
The risk of cancer isn't the only reason to refrain from eating processed meats. The Mayo Clinic explains that processed meats are also high in sodium (not just sodium nitrate) and saturated fats — both of which can exacerbate health risks.
Plus, an analysis of dietary factors on health outcomes in the United States found that eating processed meats was also linked to heart disease, stroke and type 2 diabetes, per March 2017 research in the Journal of the American Medical Association.
The best way to steer clear of nitrates is to simply avoid processed meats. If you eat meat, the Mayo Clinic advises choosing lean, fresh meats and poultry and to keep serving sizes small (not more than 3 ounces). And if you're concerned about the negative effects of sodium nitrate, try to buy organic whenever possible. As mentioned, sodium nitrate is often used in pesticides, which can often make their way into non-organic meat.
- National Center for Biotechnology Information: "Sodium Nitrate"
- Journal of the American Heart Association: "Dietary Nitrate and the Epidemiology of Cardiovascular Disease: Report From a National Heart, Lung, and Blood Institute Workshop"
- Journal of the American Heart Association: "Inorganic Nitrate in Angina Study"
- International Agency of Research on Cancer: "IARC Monographs Evaluate Consumption of Red Meat and Processed Meat"
- Harvard T. H. Chan School of Public Health: "WHO Report Says Eating Processed Meat Is Carcinogenic: Understanding the Findings"
- Mayo Clinic: "Does the Sodium Nitrate in Processed Meat Increase My Risk of Heart Disease?"
- Journal of the American Medical Association: "Association Between Dietary Factors and Mortality From Heart Disease, Stroke, and Type 2 Diabetes in the United States"
- Toxicological Research: "Distribution of Seven N-Nitrosamines in Food"