Most of us are aware that food companies use additives to extend the shelf life of their products. But how many of us know what these preservatives are, and, more importantly, what they do to our bodies?

Sodium nitrate is a kind of salt that has long been used to preserve foods. Ever heard of cured meat? Well, you can find it in many foods including bacon, beef jerky, ham, hot dogs, lunch meat, salami, and smoked fish. It creates a distinct flavor, controls lipid oxidation, and acts as an antimicrobial.

Sodium nitrate can be found in plants and unregulated drinking water. Nitrogen is turned into sodium nitrate in soil and is necessary for plant growth. Plants absorb sodium nitrate from the soil in varying amounts. Vegetables with high levels of sodium nitrate include spinach, radishes, lettuce, celery, carrots, cabbage, and beets. According to a 2009 study, approximately 80 percent of dietary nitrates in a person’s diet are obtained from vegetable consumption.

Nitrates are a natural part of any normal diet. However, some research suggests that high levels can cause problems such as colorectal cancer. Other diseases such as leukemia, non-Hodgkin lymphoma, heart disease, and ovarian, stomach, esophageal, pancreatic and thyroid cancers, may be linked to excessive consumption of sodium nitrate.

The nitrate levels that are associated with these diseases are hard to get from natural foods. Also, foods that naturally contain nitrates also contain things such as vitamin C, which may protect the body from developing the diseases listed above.

According to the Centers for Disease Control and Prevention (CDC), your daily intake of sodium nitrate shouldn’t be more than 3.7 milligrams per kilo of body weight. So, for example, a person who weighs 150 pounds should not consume more than 0.25 grams of sodium nitrate per day. However, since the amount of these preservatives is not listed on food labels, it is hard to know how much you are getting on a daily basis.

Nitrate poisoning is a serious issue that affects infants and can cause a blood disorder known as methemoglobinemia. Infants can get nitrate poisoning when the water used to make formula or baby food comes from unregulated wells. According to one study, up to 15 million Americans rely on unregulated wells for their drinking water.

Sodium nitrate is a natural part of any diet, and while excess amounts can be bad for you, it also has a place in medicine.

For example, a study in the New England Journal of Medicine concluded that dietary supplements of inorganic nitrate can reduce blood pressure.

An easy way to avoid excessive sodium nitrate intake is to limit how much cured meat is in your diet. This can also help you avoid the risk of high blood pressure.

Eating organic food is another good way to avoid taking in too many nitrates, since organic food isn’t grown with synthetic nitrogen fertilizers, which boost nitrate content in crops.

Antioxidant rich foods that are high in vitamin C can also decrease the conversion of nitrates.