If you have ever had symptoms of a heart attack, you may have been given some form of nitrates as an antidote to relieve chest pain and head off cardiac arrest. When appropriately administered, nitrates can be life-saving medications. But their misuse or excessive ingestion can be harmful or even deadly.
Nitrates Properties and Use
Nitrates are negatively charged nitrogen ions bound to two oxygen molecules, naturally found in soil, water and food. While ineffective in small doses, larger doses have an impact on human blood vessels. Because nitrates relax the tissue of the arterial walls, they are effective vasodiators, rapidly lowering blood pressure to allow blood to flow more freely through the circulatory system and ease the workload of the heart. According to the Texas Heart Institute, nitrates are used to treat angina, which is chest pain caused by restricted blood and oxygen flow to the heart that can lead to heart attack. Nitrates are also given to patients with congestive heart failure to ease symptoms.
Effects of Nitrates
Despite their effectiveness as vasodilators, nitrates can also be harmful to human health. When ingested, nitrates interact with bacteria in saliva and are broken down into nitrites. According to the Argonne National Laboratory, when ingested in large amounts, nitrites can interfere with hemoglobin, the oxygen-carrying protein in red blood cells, converting it to methemoglobin and inhibiting its ability to bind to and transport oxygen, a condition known as methemoglobinemia. Studies link methemoglobinemia caused by nitrites to cyanosis that can lead to unconsciousness and death.
Nitrates and Blood Pressure
While often useful for treating coronary artery disease, nitrates taken inappropriately can cause a dangerously rapid drop in blood pressure that can be fatal. Certain pharmaceuticals mixed with nitrates can form a deadly cocktail that causes the heart to stop. Medicines like Viagra, Cialis and Levitra taken to treat erectile dysfunction and other medications taken for hypertension should not be taken within 24 hours of taking nitrates. Alcohol can increase the effects of nitrates, and smoking can diminish the effects.
Non-Pharmaceutical Sources of Nitrates
In addition to pharmaceutical use, inorganic nitrates are used in agriculture as nitrogen fertilizers. Runoff of fertilizers into our fresh water supplies is of great concern to municipalities, which routinely monitor nitrate levels in drinking water. According to the Wisconsin Department of Natural Resources, high concentrations of nitrates in drinking water can pose a threat to unborn children and infants when ingested in unsafe amounts by pregnant or nursing mothers. Nitrates are also used in the form of sodium nitrate in processing of cured meats like breakfast and deli meats and hams. According to Martha Grogan, M.D., of the Mayo Clinic, sodium nitrate can damage blood vessels, causing them to constrict and harden, increasing blood pressure. Dr. Grogan recommends limiting your ingestion of cured meats, opting instead for fresh lean meats and poultry.
References
- Texas A & M University: Measuring Nitrates and Their Effect on Water Quality
- Argonne National Laboratory: Environmental Science Division: Human Health Fact Sheet, August 2005: Nitrate and Nitrite
- Wisconsin Department of Natural Resources: Nitrate
- Mayo Clinic: Nutrition and Healthy Eating: Does Sodium Nitrate in Processed Meat Increase My Risk of Heart Disease?: Martha Grogan, MD
- Texas Heart Institute: Nitrates
