Which impact do nitrates have on our health?
Nitrates are the salts of nitric acid, which accumulate in products and water in excess of nitrogen fertilizers in the soil. Researchers from the United States, Germany, Czechoslovakia, and Russia have found that nitrates can cause methemoglobinemia in humans, stomach cancer, negatively affect the nervous and cardiovascular systems, and the development of embryos. Methemoglobinemia is oxygen starvation (hypoxia), caused by the transition of hemoglobin of blood into methemoglobin, which is not able to carry oxygen. Methemoglobin is formed when nitrate enters the bloodstream. When the content of methaemoglobin in the blood of about 15% appears lethargy, drowsiness, with a content of more than 50%, death occurs, similar to death from suffocation. The disease is characterized by shortness of breath, tachycardia, cyanosis in severe cases – loss of consciousness, convulsions, death.
How dangerous are nitrates for kids and breastfeeding moms?
Poisoning occurs with the use of water and products of plant and animal origin with a high content of nitrates or nitrites. The children of the first months of life are most sensitive to excess nitrates. According to some reports, there were cases of poisoning of children with vegetable juices and vegetables with a high content of nitrates, in particular carrot juice. The source of poisoning was juice, which was drunk 1-2 days after preparation. In 1 liter of juice up to 770 mg of nitrates accumulated.
If mothers consume highly nutritious vegetables, nitrates enter breast milk: it is not a barrier to nitrates. In the mother’s body, there is a mechanism of protection against nitrates, but its possibilities are limited. If the mother consumes foods high in nitrates (cabbage, carrots, cucumbers, zucchini, dill, spinach), then they inevitably fall into breast milk. Counter-nitrate mechanisms in a child are formed only when he is one year old)
Metabolism of nitrates in the human body
When you use foods with a high content of nitrates, not only nitrates but also their metabolites enter your body: nitrites and their compounds. The exact balance of the arrival and consumption of nitrates in the body has not yet become possible. The fact is that nitrates not only enter the body from the outside, but also form inside. In small quantities, nitrates are constantly present in the human body, as in plants, and do not cause negative phenomena. All troubles begin when nitrates accumulate. In the body, nitrates come with water and food, then they are absorbed into the small intestine into the blood. Excreted mainly with urine. In addition, they are excreted in human milk. The amount of nitrates in milk depends on the quantity and quality of vegetables in the mother’s diet and the duration of feeding. The maximum content of nitrates in milk is in the first month after childbirth, then it gradually decreases.
The main reason for all the negative consequences are not so much nitrates, as their metabolites – nitrites. Nitrites, interacting with hemoglobin, form methemoglobin, which is not capable of carrying oxygen. As a result, the oxygen capacity of the blood decreases and hypoxia develops (oxygen starvation). For the formation of 2000 mg of methaemoglobin, 1 mg of sodium nitrite is sufficient. In a normal state, a person has about 2% of methaemoglobin in the blood. If the content of methemoglobin increases to 30%, then symptoms of acute poisoning (dyspnea, tachycardia, cyanosis, weakness, headache) appear, and death may occur with 50% methaemoglobin. The concentration of methemoglobin in the blood is regulated by methaemoglobin reductase, which restores methhemoglobin to hemoglobin. Methemoglobin reductase begins to develop in humans only from the age of three months, so children under one year old, and especially up to three months, are defenseless. In the literature on the chemistry of nitrates, there is no report on the isolation of nitrites from the human body. The content of meghemoglobin increases to dangerous values only when nitrite enters the bloodstream.
Which factors influence the accumulation of nitrates?
Nitrates are restored into nitrites by various microorganisms that colonize the intestine. The degree of recovery of nitrates, as in the storage of products, depends on the same factors: the amount of nitrates in products and the conditions of life of microorganisms. A weakly alkaline and neutral medium is favorable for the development of the intestinal microflora. The most sensitive to nitrates are people with a low acidity of the stomach. They are children under one year old and suffer from gastritis and dyspepsia. In such people, the microflora of the large intestine can penetrate into the stomach, and then the percentage of nitrate reduction is sharply increased compared to healthy people.
Over the last 10-15 years, more than 1000 cases of nitrate-nitrite methaemoglobinaemia have been described, among which 100 resulted into death. In healthy people, mild forms of poisoning were observed with a content of nitrates in water or food more than 80-100 mg / l. And in children with dyspepsia, intoxication occurred when drinking water with a nitrate content of 50 mg / l.