Nitrates and Nitrites in Food: Are They Harmful?

Nitrates and nitrites might sound like complicated chemicals, but they’re all around us—found in soil, water, and food. While they play important roles in our health, too many can cause problems, especially for infants and pregnant women. These compounds show up in everything from vegetables to processed meats and even in the water we drink. In this article, we’ll examine nitrates and nitrites, how they affect our health, and simple ways to manage their levels.

What Are Nitrates and Nitrites?

Nitrates and nitrites are chemical compounds made of nitrogen and oxygen atoms. These compounds are found naturally in soil, water, and air. Plants and animals need inorganic nitrates and nitrites to live and thrive. The human body also makes these chemicals. 

As mentioned, nitrates and nitrites are naturally present in soil, water, and air. Animal waste also adds to nitrate compounds in the environment. In industry, nitrates are used mainly in nitrogen fertilizers for crops. 

Nitrates and nitrites are highly solubilized. They dissolve quickly in water and reach groundwater and surface water. Plants and crops absorb these chemicals from the soil, and water can also convert them to nitrogen. 

Additional industrial uses of nitrates and nitrites are in food preservatives, certain drugs, and explosives.

The chemical composition of nitrates is NO3, and nitrites is NO2. By losing an oxygen atom, nitrates can turn into nitrites. Nitrites can further turn into nitric oxide (a beneficial substance) or nitrosamines (a toxic substance).

What Do Nitrates Do In The Body?  

Are Nitrates Bad For You?

Humans need nitrates for natural processes in the body to live and grow. As noted, the human body naturally produces these chemical compounds. We also obtain dietary nitrate from foods. However, a high nitrate level in the body can be harmful. 

Benefits and Positive Effects 

Food Preservation: Nitrates and nitrites are food preservatives commonly added to processed meats such as bacon, ham, sausages, and hot dogs. They prevent the growth of harmful bacteria in meat and give it a salty flavor and palatable appearance.

Digestive Health: Studies have found that nitrates and nitrites are an effective defense against bacteria in the gastrointestinal tract, such as Salmonella and Yersinia, which cause gastroenteritis. 

These compounds may have additional roles in gastrointestinal motility and microcirculation. 

Cardiovascular Health: Nitrates may play a role in regulating platelet activity. They may have blood pressure lowering, antiplatelet, and cell protective effects. Scientists believe this is because nitrites (NO2) can lose an oxygen atom and change to nitric oxide (NO). Nitric oxide functions as a signaling molecule in the body. For example, it helps with vasodilation (widening of blood vessels) by relaxing muscles in blood vessel walls. This leads to a lowering of blood pressure.

Physical Performance: Research suggests nitrates may improve physical performance, including endurance during high-intensity exercise, by improving mitochondrial efficiency. Mitochondria are parts of cells that produce energy.

Potential Risks and Concerns

Methemoglobinemia: Eating food or drinking water with high nitrate levels can lead to a condition called methemoglobinemia, in which there is a decreased ability of blood to carry oxygen to tissues throughout the body. 

Blue baby syndrome due to decreased oxygen has been reported in infants younger than 6 months of age who were given baby formula made with drinking water containing high levels of nitrates. 

Symptoms of nitrate toxicity include low blood pressure, fast heart rate, headaches, stomach cramps, and vomiting. Some people have died from nitrate poisoning. 

Thyroid Function: Animal studies indicate that high nitrate intake can lead to changes in thyroid function.

Cancer Risk: Consumption of meat, particularly red meat, is a known risk factor for colon cancer. Many people believe that exposure to high levels of nitrates and nitrites in meats is responsible for the increased risk of digestive tract cancers, including colorectal cancer and stomach cancer. 

However, the U.S. Department of Health and Human Services (HHS) has not studied these compounds as potential carcinogens (cancer-causing chemicals), and the Environmental Protection Agency (EPA) has not classified them for carcinogenicity. The International Agency for Research on Cancer (IARC) states that the presence of nitrates in stomach acids may lead to the formation of cancer-causing N-nitroso compounds.

Pregnancy Complications: Maternal dietary intake of nitrates, nitrites, and nitrosamines can lead to the formation of harmful N-nitroso compounds in the stomach. Animal studies suggest that these compounds can be teratogenic and may result in congenital disabilities in the offspring. 

High nitrate and nitrite levels in pregnant women due to excessive levels in drinking water can also increase the risk of premature delivery.

Food and Nitrates

What Foods Are High in Nitrates?

• Processed and cured meats (bacon, ham, deli meat, hot dogs, sausages, pepperoni, salami, bologna, corned beef, and canned meat) may contain high sodium nitrite levels. Cooking these high-protein foods at high temperatures can cause toxic substances called nitrosamines to form. 

• Animal-origin foods with nitrate ion content include dairy products and fish.

• Vegetables with high nitrate concentrations include spinach, celery, lettuce, beetroot, cucumber, carrot, cabbage, and broccoli. Notably, vegetables are less likely to form toxic substances like nitrosamines because they are less commonly cooked at high heat and do not have high protein content.

Dietary Implications and Guidelines  

Most people are not exposed to high nitrate levels from dietary sources that would cause health problems. 

General dietary guidelines recommend avoiding foods with high nitrate levels, especially for infants and young children. 

Which Medications Are Nitrates?

Some medications used to treat cardiovascular disease, including angina (chest pain), heart failure, acute coronary syndrome, and high blood pressure, are nitrates. Examples include nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate. These drugs work by causing vasodilation (widening of blood vessels) by forming nitric oxide.

Nitrates In Water  

Drinking Water and Nitrate Concentration  

You cannot taste, smell, or see nitrate in drinking water. However, consuming high amounts of nitrate can be harmful to health. Infants are the most sensitive group to these health effects and can develop methemoglobinemia (bluish color) due to a reduced capacity of blood to carry oxygen.

Environmental Impact and Safety Standards  

The U.S. Environmental Protection Agency (EPA) has identified 10 mg/L (10 milligrams of nitrate in 1 liter of drinking water) or 1 part per million as the safe maximum contaminant level.

Nitrate concentrations can be measured in blood and urine. However, these tests are useless in identifying high nitrate exposure because the human body naturally makes these chemical compounds.

Managing Nitrate and Nitrite Intake  

Are Nitrates In Deli Meat Bad For You?

Processed and cured meats, such as deli meat, bacon, and ham, are a significant source of dietary nitrate. As mentioned, excessive intake can cause harm. Therefore, the recommendation is to limit your intake of these foods to prevent a high nitrate level in your body.

Keep in mind that, by law,  food manufacturers must limit the amount of nitrites in processed meats because of the dangers associated with nitrosamines. They also have to add vitamin C to reduce nitrosamine formation. As a result of these regulations, the processed meat sold in the US today contains less nitrite than it did some decades ago.

Is Bacon a Nitrite or Nitrate?

Bacon contains nitrites, not nitrates, which are used in the curing process to help preserve the meat and give it its characteristic color and flavor. 

How To Reduce Risk and Negative Effects

• If you use water from private wells or live near agricultural fields, gather water quality data and have your water nitrate level checked. 

• Make sure children do not play in areas where fertilizers are used.

• Check labels for ingredients and look for food additives such as potassium nitrite (E249), sodium nitrite (E250), sodium nitrate (E251), and potassium nitrate (E252).

• Choose nitrate-free meats, for example, from farmers' markets or local suppliers.

• Cook meat at lower temperatures or microwave it.

• Do not make baby formula with water that may contain high levels of nitrates, such as well water.

How To Flush Nitrates Out Of Your Body?

1. Minimize consumption of processed and cured meats.

2. Check labels and avoid foods that contain additives such as sodium and potassium nitrate or nitrite.

3. Eat organic food.

4. Check water samples from private wells for nitrate in drinking water.

5. Eat a diet high in vitamin C and other antioxidants, which prevent the conversion of nitrates and nitrites to harmful nitrosamines.