Nitrosamines and their relationship with cancer

| Nitrosamines are products with a high carcinogenic potential that are formed from nitrates and nitrites and influence cancer prevention.

Nitrates, nitrites, nitrosamides and nitrosamines are called N-nitroso compounds and they are at the origin of some types of cancer.

Where they are

Nitrates are abundant substances in soil and water, so we can find them in drinking water, in vegetables such as spinach, in treated foods (salty, pickles, etc.) and in tobacco.

Nitrites are additives used in the food industry to preserve the meat and give it flavor and color. They are also in vegetables. Furthermore, nitrates can be converted to nitrites by a chemical reduction reaction that can take place in the intestine by the action of bacteria present there.

Nitrates and nitrites, in turn, give rise to nitrosamines and nitrosamides (through chemical nitrosation reactions). Under low pH conditions and in the presence of amines, nitrates and nitrites give rise to nitrosamines; in and in the presence of amides, nitrates and nitrites give rise to nitrosamides. Amines and amides are found in various foods and could also be derived from digested proteins. These low pH conditions can occur in the food itself, and in the stomach and digestive tract. Nitrosation processes are promoted or accelerated by bacteria present in the digestive tract.

In this way, the substances nitrosates have been implicated in stomach cancers and esophagus. However, these substances are not the final carcinogen: they require their activation by enzymes or proteins of the liver that we know as the microsomal P-450 system.

How does vitamin C affect nitrosates?

Vitamin C inhibits the formation of nitrosamines in vitro and could help protect us from nitrosated substances in vivo. It has been said that the increase in the intake of this vitamin would explain, at least in part, the decrease in the incidence of gastric cancer observed in recent years.