Processed Meats and Health Risks

by Rachael Link, MS, RD

Since being classified as carcinogenic in 2015, processed meats have garnered a good amount of public interest, and emerging research has continued to link processed meat intake to more and more deadly conditions. So what is it about processed meats that makes them so detrimental to health? Part of the problem lies in their content of a compound called sodium nitrite.

While processed meat is pumped full of many unhealthy and downright dangerous ingredients, sodium nitrite stands out as one of the worst. This is because it can be converted into a compound that may be associated with cancer, Alzheimer’s disease and even diabetes. Not only that, but a toxicity of sodium nitrite can deprive your cells of oxygen, resulting in some potentially deadly side effects.

If that doesn’t convince you to rethink your daily bacon breakfast, keep reading to find out more about this dangerous compound and how it may affect your health.

What Is Sodium Nitrite? What Are Nitrites?

Sodium nitrite is an ingredient frequently found in processed meats that acts as a preservative and protects against the growth of harmful bacteria. Other sodium nitrite uses include adding a salty flavor and boosting the reddish-pink color that’s characteristic to processed meats.

Nitrites are one of the primary ingredients in sodium nitrite. Nitrites are a chemical compound composed of one nitrogen atom with two atoms of oxygen. When you consume foods with nitrites, they can turn into nitric oxide, which plays an important role in health and disease. (1)

Unfortunately, nitrites can also turn into nitrosamines, which are harmful compounds that have been linked with many adverse effects on health. Nitrosamine formation takes place when nitrites are in the presence of amino acids and are exposed to high heat, which is why nitrite-rich processed meats are more likely to contain these disease-causing compounds.

Limiting your intake of foods high in sodium nitrite is essential when it comes to minimizing your risk of chronic disease and optimizing your health.

Sodium Nitrite Dangers

1. Contains Cancer-Causing Compounds

When combined with high heat, nitrites can form nitrosamines, which are cancer-causing compounds that can have deleterious effects on health. In fact, just recently the World Health Organization officially classified processed meats as “carcinogenic to humans” based on increasing evidence that demonstrated a link between processed meat consumption and a higher risk of cancer. (2)

One review comprising 61 studies, for instance, showed that a higher intake of nitrosamines and nitrites was associated with a higher risk of stomach cancer. (3) Other studies, including meta-analyses, cohort studies and research reviews, have found similar associations between sodium nitrite and cancer, reporting that a higher intake of processed meats may be linked to an increased risk of colorectal, breast and bladder cancers. (4, 5, 6)

2. May Raise the Risk of Type 1 Diabetes

Type 1 diabetes is a chronic autoimmune condition in which the pancreas is unable to produce enough insulin. Insulin is an important hormone that’s responsible for transporting glucose (sugar) out of the bloodstream and into the cells and tissues, where it can be used as fuel. A lack of insulin causes high blood sugar levels, which can lead to diabetes symptoms like frequent urination, unintentional weight loss and fatigue.

Note that this type of diabetes is different from type 2 diabetes, which can occur at any age and can be caused by a combination of genetics and lifestyle factors. Type 1 diabetes, on the other hand, occurs when the immune system mistakenly begins attacking the body’s own insulin-producing pancreatic cells and is usually diagnosed during adolescence, with adults accounting for only one-fourth of new type 1 diabetes diagnoses. (7)

Some studies have found that an increased intake of nitrites may be associated with a greater risk of type 1 diabetes. A study published in Diabetes Medicine, for example, found that a higher intake of nitrites was associated with a higher risk of developing type 1 diabetes in children. (8) Meanwhile, other studies on populations in Colorado and Yorkshire, England have shown that drinking water with high levels of nitrates was linked to a higher risk of type 1 diabetes. (9, 10)

3. Impairs Oxygen Transport

Methemoglobinemia is a condition characterized by the presence of methemoglobin in the blood, which is a type of hemoglobin that contains a different form of iron. Because your blood contains ferric iron instead of ferrous iron, it’s unable to deliver oxygen to your cells and tissues efficiently, resulting in symptoms like a bluish coloring of the skin, headaches, fatigue and developmental delays.

A growing body of research has shown that nitrites can contribute to this deadly condition, with many research studies showing that it could be caused by drinking contaminated nitrite-rich water or eating high-nitrite meats. (11, 12, 13) For this reason, some recommend moderating consumption of high-nitrate baby foods, such as bananas, spinach, carrots and beets, to help prevent methemoglobinemia in infants. (14)

4. May Be Linked to Alzheimer’s

According to some studies, the potential sodium nitrite hazards may extend well beyond causing cancer and diabetes. In fact, some evidence suggests that a high intake of sodium nitrite may even be linked to brain health.

An animal study published in the Journal of Alzheimer’s Disease found that nitrosamine exposure caused impaired motor function and learning, neurodegeneration, and an increase in the levels of certain proteins in the brain that build up and form plaque, contributing to the development of Alzheimer’s disease. (15) Multiple other studies have shown that a diet rich in processed meats may be associated with a higher risk of cognitive deficits and neurological conditions. (16, 17)

However, current research is still limited on the potential effects of sodium nitrite on brain health. More well-designed studies on humans are needed to determine what role nitrite intake may play in the development of Alzheimer’s disease.

Foods High in Sodium Nitrite

Sodium nitrite in food is especially prevalent in processed meats. Certain types of vegetables also contain sodium nitrate, which can be converted to sodium nitrite in small amounts. However, these vegetables do not seem to pose the same health risks as the nitrites in food sources like processed meats.

A few examples of foods that are high in sodium nitrite include:

• Ham
• Hot dogs
• Bacon
• Salami
• Sausage
• Corned beef
• Bologna
• Beef jerky
• Lunch meat
• Salted and cured meat
• Smoked meat

Nitrites vs. Nitrates

To really understand what sodium nitrite is, it’s also important to understand what are nitrates vs. nitrites and how each one can impact health.

Nitrates and nitrites are two compounds with a very similar chemical structure. Nitrates consist of a nitrogen atom bonded to three oxygen atoms while nitrates are made up of a nitrogen atom with only two oxygen atoms.

Nitrates are found in many sources but are especially prevalent in vegetables. In fact, it’s estimated that 80 percent of nitrate consumption comes from vegetables while fruits and processed meats account for the remainder. (18) Your body also produces nitrates, which are excreted in the saliva. For this reason, the levels of nitrates in your saliva are often 10–20 times higher than the amount found in your blood. (19)

Nitrates in food can turn into either nitric oxide or nitrites. Nitric oxide has actually been associated with some positive effects on health. In particular, nitric oxide may act as a vasodilator to help prevent high blood pressure symptoms and can even improve exercise performance. (20, 21)

Some of the nitrates that you eat will be converted into nitrites, although this amount is usually very small. Like nitrates, nitrites can also turn into nitric oxide. However, when exposed to high heat and in the presence of amino acids, nitrites can turn into nitrosamines, which can come with a host of negative health effects and may even be linked to a higher risk of cancer and other chronic conditions.

Sodium Nitrite vs. Sodium Nitrate

Sodium nitrate is a type of natural salt made up of sodium, nitrogen and oxygen. It’s also sometimes called Chile saltpeter, earning its name because large deposits can be found in Chile.

In the past, sodium nitrate was used to help preserve and enhance the flavor profile of meats. However, when food manufacturers discovered that sodium nitrate reacts with the bacteria found in meat to form sodium nitrite, they began adding sodium nitrite directly to meat instead to help aid in preservation.

Today, most processed meats contain sodium nitrite to prevent spoilage and inhibit the growth of bacteria that cause botulism. Sodium nitrite also adds a salty flavor to foods and gives meat a characteristic red/pink hue.

Alternatives to Sodium Nitrite Foods

The easiest way to cut down on your intake of sodium nitrite foods is to simply swap out the lunch meat and processed junk for unprocessed types of meat. Opt for raw meat that hasn’t been smoked, cured or salted, and use healthy methods of cooking, such as steaming, poaching, roasting or stir-frying. With just a little creativity, there are also plenty of ways to give your favorite recipes a healthy twist to minimize your intake of sodium nitrite.

Instead of additive-laden hot dogs, try using baked chicken tenders for a healthier take on the hot dog. If you’re feeling even more adventurous, try out some meat-free hot dog alternatives, like carrot dogs topped with seasonings and veggies to add a punch of flavor.

You can also try tempeh bacon or mushrooms in place of regular bacon in your next BLT sandwich or morning omelette to skip the sodium nitrite and get an extra dose of important vitamins and minerals instead.

For sandwiches on the go, trade in your processed deli meats for lentil or bean burgers, hard-boiled eggs, tuna, or roast beef. You can also experiment with other nutritious ingredients like hummus, fresh veggies and legumes.

If you can’t imagine giving up the hot dogs or bacon, you can also check your local grocery store for “nitrite-free” varieties of your favorite foods. However, you should still keep your intake of these foods in moderation as they may still contain other questionable ingredients and additives that can be harmful to your health.

History

Food preservation methods like curing date back thousands of years to ancient times. Ancient Greeks and Romans, for example, used salt to preserve meat and fish. These cured meats even played a central role in religious ceremonies, where salted meats would be used as an offering to the gods.

In North America, the Plains Indians practiced smoking meat by hanging fish near smoldering wood for anywhere between a few hours and a few days. This was especially important for tribes in the north, who would catch large amounts of fish during spawning season, preserve them and consume them all throughout the winter.

Years later during the Age of Discovery, sailors relied on salted meats during long voyages. By the 19th century, new products were being rapidly developed and rolled out. Canned salt meat products like corned beef helped innovate the way that we preserve and consume food. Around the beginning of the 20th century, producers discovered that sodium nitrate interacts with the bacteria in meat and is converted to sodium nitrite, which spurred many manufacturers to begin adding sodium nitrite directly to their products.

In the 1970s, scientists made the shocking discovery that sodium nitrite is converted to nitrosamine when it’s heated above 266 degrees Fahrenheit. The USDA took action by setting limits on the amount of nitrites that can be added to processed meats. Additionally, food manufacturers are required to include vitamin C in products that contain nitrites, which can help reduce the formation of nitrosamines.

Other Precautions

In addition to increasing the risk of chronic disease and and blocking oxygen transport, sodium nitrite can also cause acute toxicity when consumed in very large amounts. According to the World Health Organization, 10 grams of nitrites is considered fatal, but doses of just two grams daily have resulted in death. (22) Symptoms of toxicity can include nausea, vertigo, bluish skin, vomiting, convulsions and headaches. (23)

Also note that sodium nitrite is just one of the harmful compounds found in processed meat, and unfortunately, opting for nitrite-free meats doesn’t make them healthy. In fact, processed meat consumption has been associated with a higher risk of many types of chronic disease, including heart disease, chronic obstructive pulmonary disease (COPD), high blood pressure and cancer. (24, 25, 26, 27) Other potentially dangerous compounds found in certain types of processed meats besides sodium nitrite include polycyclic aromatic hydrocarbons, sodium chloride and heterocyclic amines.

Final Thoughts

• Sodium nitrite is an ingredient frequently found in processed meats that’s used to prevent the growth of bacteria and enhance the color and flavor of products.
• When exposed to high heat in the presence of amino acids, nitrites can turn into nitrosamines, which are harmful compounds linked to a variety of adverse health effects.
• A higher intake of nitrites may be associated with an increased risk of cancer, type 1 diabetes, Alzheimer’s disease and methemoglobinemia.
• Limit your intake of sodium nitrite and processed meat, and select more whole, nutritious foods as part of a healthy, low-sodium diet.