Nitrites are chemical compounds that contain nitrogen and oxygen. Chemically, they are a salt or an ester of nitrous acid. They are often used to cure meats, such as ham and bacon, and are responsible for their pink or red color. Nitrites differ from nitrates in that nitrates carry more oxygen than nitrites. Nitrates themselves are more stable than nitrites.
This article will discuss the differences between nitrites and nitrates, whether nitrites are bad for you, and why they can be beneficial. It will also discuss the sources of these chemicals and how to reduce exposure.
A Little Bit of Chemistry
Both nitrites and nitrates contain nitrogen and oxygen. Their difference comes in the number of oxygen atoms they carry. Nitrite’s chemical makeup has one nitrogen and two oxygen atoms (NO2), whereas nitrates contain one nitrogen and three oxygen atoms (NO3).
nitrites vs. nitrates
The main difference between nitrites and nitrates is the number of oxygen atoms they contain. Nitrates can be converted into nitrites by bacteria and enzymes (substances that speed up the rate of a specific chemical reaction) found in the mouth and body. Many experts agree that nitrates are relatively harmless until broken down into nitrites.
Are Nitrites Bad for You?
Nitrites are often converted into two types of compounds in the body. one is nitric oxide, which is helpful for the body. The other compounds are nitrosamineswhich can be damaging to the body.
Nitrites have been implicated in the risk of some cancers, such as esophageal, stomach, and colorectal cancers. However, this association is not without controversy.
Some studies report that nitrite intake alone is not associated with esophageal or gastric (stomach) cancer, while associations were found between red meat intake and esophageal (food tube) cancer.
The International Agency for Research on Cancer (IARC), which is the specialized cancer agency of the World Health Organization (WHO), has classified red as meat a group 2A carcinogen (meaning it’s probably carcinogenic to humans) and processed meats as a group 1 carcinogen (meaning it’s known to cause cancer).
Whether the nitrites in red and processed meats are linked to cancer is highly debated. On the other hand, naturally occurring nitrites have been linked to some health benefits.
Acceptable Daily Intake
There is no daily recommended intake (DRI) of nitrites and nitrates set by the Institute of Medicine (IOM). However, the Joint Expert Committee on Food Additives (JECFA) of the Food and Agriculture Organization of the United Nations/World Health Organization and the European Commission’s Scientific Committee on Food have proposed an acceptable daily intake (ADI) for nitrites.
The proposed limit is 0 to 0.07 milligrams (mg) of nitrite ion per kilogram (kg) of body weight. The Environmental Protection Agency (EPA) has set a reference dose (RfD) of 0.1 mg nitrite nitrogen per kg of body weight per day, which is equivalent to 0.33 mg nitrite ion per kg of body weight per day.
These same organizations have also set an ADI for nitrates from 0 to 3.7 mg of nitrate ion per kg of body weight. The EPA RfD for nitrate is 1.6 mg nitrate nitrogen per kg of body weight per day, which is equivalent to about 7.0 mg of nitrate ion per kg of body weight per day. These amounts seem safe for healthy infants, children, and adults.
Benefits of Nitrites
Nitrites are used in meats to help cure them and add flavor, as well as act as a broad antimicrobial to prevent bacterial growth. This inhibition of bacterial growth plays an important role in food safety and can help prevent foodborne illness.
Nitrites have also been found to be beneficial for several health problems. Nitrite that has been converted to nitric oxide has been linked to cardiovascular and metabolic regulation.
Some health benefits associated with it include decreased blood pressure levels, increased function of the endothelium (the thin membrane that lines the inside of the heart and blood vessels), improved exercise performance, reversal of metabolic syndrome (a group of co-occurring conditions that can raise your risk of stroke, heart disease, and type 2 diabetes), and improved outcomes for people with diabetes.
Due to the heart-health benefits of nitrites and nitrates, healthcare providers have been able to use them for the benefit of different heart-related medical conditions. Namely, nitroglycerinwhich is a medication that contains nitrates, is used to treat chest pain, heart failure, as well as other heart-related health problems.
Nitrosamine Formation and Risks
Nitrosamines are one of the compounds that can be formed from the breakdown of nitrites in the presence of amines (compounds that contain a basic nitrogen atom with a lone pair).
Conditions of a low pH, such as is found in the stomach, as well as the presence of inflammation and bacteria (Helicobacter pylori), may promote the conversion of nitrite to nitrosamine. However, antioxidants (substances that can prevent or slow damage to cells caused by free radicals) have been found to decrease this conversion.
Nitrosamines are also formed by cooking with high heat and temperatures, such as are often used in frying and barbecuing. Other sources of nitrosamines are smoking tobacco, beer, and contaminated drinking water. Nitrosamines have been proven to cause cancer and mutagenesis (genetic mutations) in humans.
Risks of Cooking at High Temperatures
In addition to the formation of nitrosamines at high cooking temperatures, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are formed when meats, fish, or poultry are cooked using high-temperature cooking methods. These include frying, barbecuing, or grilling directly over an open flame.
Some studies have reported HCAs and PAHs to be mutagenic (cause genetic mutations) and may increase the risk of cancer.
Foods High in Nitrites
Nitrates and nitrites are often added to foods to act as a preservative, to prevent dangerous bacterial growth, as well as to provide color and a salty flavor. They are found in cured and processed meats, including:
- deli meats
- hot dogs
How to Read Nutrition Labels
Some grocery stores sell quality bacon and other red and processed meats that are nitrate-free. To know whether they have nitrites or nitrates in them, look at the ingredients list. This will help you verify nitrites and nitrates are not used. They may be listed as:
- Potassium nitrite (E249)
- Sodium nitrite (E250)
- Sodium nitrate (E251)
- Potassium nitrate (E252)
In addition, some organic and natural ways of preserving meat may contain nitrates, one of which is using celery salt. As a result, some “nitrate-free” meats may still contain nitrates.
Other Sources of Nitrites
Besides being added to meats, nitrites and nitrates are also naturally found in some plant foods. Leafy green vegetables and some root vegetables, such as beetroot, are high in naturally occurring nitrates.
The dietary consumption of vegetables that are naturally high in nitrates and nitrites is our biggest source of nitrate and nitrite exposure. These plant-based sources are not associated with the risk of cancer but rather have been shown to have positive health effects. Additionally, they contain compounds, such as antioxidants that prevent the formation of nitrosamines.
Nitrites and nitrates also pollute some drinking water sources, especially from wide-scale agricultural fertilizer use. The meta-analysis review of data showed an association between nitrate intake from drinking water and a type of cancer in humans.
Food Preparation Tips for Lowering Exposure
Some tips to help decrease your risk of exposure to harmful nitrites and nitrosamines include:
- Eliminate or limit the amount of processed and red meats you consume.
- Avoid direct exposure of meat to an open flame or a hot metal surface.
- Avoid cooking for prolonged periods of time, especially at high temperatures.
- Use the microwave oven to cook meat instead of frying or barbecuing.
- Continuously turn or rotate meat when cooking it on a high heat source.
- Removes charred portions of meat before eating.
- Purchase high-quality nitrate-free meats from local farmers.
Nitrites are compounds found naturally in some plant foods and are often added to red and processed meats for purposes of curing, adding color and flavor, and inhibiting to bacterial growth.
Some studies suggest an association between nitrites, particularly when broken down into nitrosamines, to cancer. Other studies show heart and other health benefits of nitrites when broken down into nitric oxide.
You can decrease your exposure to harmful nitrites by avoiding red meat, choosing high-quality nitrate-free meats, and avoiding high-temperature cooking, such as panfrying and barbecuing.
A Word From Verywell
It can be confusing knowing what to eat to stay healthy, nitrates and nitrites included. Choosing to limit or avoid certain types of foods, such as highly processed meats, may decrease your exposure to harmful nitrites and other substances that may negatively impact your health.
Choosing a diet based on whole foods, such as vegetables, fruits, whole grains, vegetables, and lean protein, can help put you on a path towards health and wellness.
Frequently Asked Questions
What’s the link between nitrites and cancer?
Nitrites can be broken down into compounds called nitrosamines. Nitrosamines have been proven to cause cancer and genetic and DNA mutations in humans.
Some studies have reported an increased risk of stomach, colon, and kidney cancers in people with higher intakes of meat and nitrates in water compared with low intakes of both.
Are nitrites in aquariums bad for fish?
According to the Florida Department of Agriculture and Consumer Services, nitrites in water can be toxic to fish. Nitrates can bind to the oxygen-carrying protein in blood (hemoglobin) to form methemoglobin.
As opposed to hemoglobin, methemoglobin does not carry oxygen throughout the fish’s body. This may cause the fish to suffocate even when there is enough oxygen available.
Should people with erectile dysfunction avoid nitrates?
It has long been contraindicated (advised against) for people taking phosphodiesterase type 5 (PDE5) inhibitors like Viagra (sildenafil) for erectile dysfunction (ED) to also take medications with nitrates due to a risk for unsafe drops in blood pressure.
However, a 2022 study did not find any significant adverse heart problems in people taking nitrates along with these medications.
To ensure safety, always talk with your healthcare provider or pharmacist before taking nitrates if you also take medication for ED.
Do water filters lower nitrite and nitrate levels?
Mechanical water filters, chemical disinfection (such as chlorination), and boiling your water do not remove nitrates from water. You can successfully lower nitrate levels in your water using treatment processes, such as distillation, ion exchange, and reverse osmosis.