Unfortunately, scrolling through the chronicles of recent years, episodes of food poisoning caused by the consumption of bluefin tuna. However, each time the results of the investigations arrive at the same conclusion: the fish has nothing to do with it, the substances illegally used to revive its color are responsible for the poisoning: the nitrates. Prohibited in this case, the use of nitrates is instead permitted as a preservative in many food products, alone or together with similar substances: nitriteswhich are also potentially harmful.
Naturally, the law establishes maximum limits of use, but to complicate matters there is the fact that nitrates and nitrites are naturally present in various vegetable products that we bring to the table, and we can even find them dissolved in the water we drink. Then it is worth getting to know them better.
Why nitrates and nitrites are bad for you
The first reason is that they favor certain types of cancer, especially in the stomach and esophagus. In fact, neither nitrates nor nitrites directly induce the onset of cancer, but once ingested they can undergo a series of chemical transformations in our body which lead to the formation of nitrosamines, which are carcinogenic. Here’s what happens: nitrates, coming into contact with saliva, can be transformed into nitrites and these, once they arrive in the stomach, become nitrous acid, capable of combining with some substances present in foods to form the infamous nitrosamines, which the prestigious United States Food and Drug Administration considers among the most dangerous carcinogens.
The rule is therefore simple: we try to ingest as few nitrates as possible, and even more so, less nitrites. Especially since cancer is not the only risk associated with these substances. In fact, nitrites can also bind with the hemoglobin, the blood protein that carries oxygen, preventing it from performing its function and hindering breathing. In the cases of serious poisoning that occur from time to time, it is precisely the lack of oxygenation of the blood that determines the most worrying effects, especially for children who may experience sometimes lethal breathing difficulties.
Nitrates and nitrites, plant food
Harmful to humans, nitrates and nitrites are instead beneficial for plants which obtain the nitrogen necessary for their growth. It was precisely the discovery of the usefulness of nitrates and nitrites for plants that prompted farmers to enrich the soil with the use of fertilizers, chemical or naturalwho are rich in it.
As Paracelsus argued a few centuries ago, however, it is the dose that makes the difference between medicine and poison: if used wisely and in the right quantities, the so-called “nitrogen” fertilizers, containing nitrates, allow to improve the yields of the land and increase its production, but when it is exaggerated (as often happens in intensive agriculture) a double negative effect is created: the first is that the vegetables absorb large quantities of nitrates which then end up on the plate, the second is that, penetrating deeply into the soil, the nitrates they can reach the groundwater and we risk finding them not only on the plate but also in the glass.
Signs to keep in mind
Adding to the problem of nitrates and nitrites naturally present in food and water is the possibility of using them as additives in a number of food products. In fact, these substances act as effective preservatives, avoiding the development of microorganisms dangerous to human health, first of all botulinum toxin. It seems strange that the use of substances considered harmful as additives is permitted, but the principle that justifies it is that of risk/benefit ratio: rather than run the risk of very serious poisoning such as that caused by botoxthe risk of ingesting substances that could cause problems in the future, gradually accumulating in the body, is considered acceptable.
In short, you choose the lesser of evils, but it goes without saying that if you manage to avoid the intake of nitrates and nitrites it is only good for our health. The first thing to do is therefore read the label of the products purchased: these substances are often hidden behind the abbreviations E251 and E252 (nitrates), E249 and E250 (nitrites), and, comparing the labels, it is not difficult to realize that there is no shortage of nitrate and nitrite-free alternatives today. Indeed, many packs bear the words “nitrate-free”, as a guarantee of a quality product.
Foods most at risk
Wanting to draw a picture of the foods most at risk for the content of nitrates and nitrites, we must distinguish the products to which they are added as additives from those in which they are naturally present at the origin. Typically nitrates and nitrites are used in the production of canned meats and sausagesbut they can also be found in some marinated fish and, rarely, in some cheeses.
On the other hand, considering nitrates in fruit and vegetables, their presence depends on several factors, such as the amount and type of fertilizers and even the amount of sunlight they absorb. In general, it can be said that organic products and products from integrated agriculture contain less nitrates, just as fruit, vegetables and cereals grown in open fields are preferable to those grown in greenhouses.
The false “without” nitrates and nitrites
In the cured meats sector, companies have long been looking for production methods that make it possible to minimize or even avoid the addition of nitrates and nitrites. By processing the meat in compliance with the cold chain and with controlled humidity, excellent results can be obtained by reducing the use of these additives well below the legal limits.
If this way of working is an indication of seriousness and reliability, the same cannot be said of those producers who, driven by the trend of “without” products, have marketed cured meats “without nitrates and nitrites” resorting to a stratagem aimed only at circumvent the law. Knowing that some aromatic plants, such as celery, are naturally rich in nitrateshave used their concentrated extracts to introduce these substances without having to declare them as additives.
The nitrates in the water
Fertilizer nitrates can penetrate deep into the soil and even reach groundwater, so we can find them in both tap and mineral water. The law establishes a maximum presence of nitrates in drinking water of less than 50 milligrams per litre, while nitrites must be practically absent (0.5 mg/l).
In the past, in many areas it was difficult to supply water that complied with these limits and it was necessary to resort to specific measures that derogated from the law. Today, on the other hand, one can be quite sure, because cultivation techniques have improved and controls are scrupulous. Regarding bottled mineral waters, the Italian law provides for two limits: 45 mg/l in ordinary mineral waters And 10 mg/l in those intended for early childhood. Therefore, it is important to check the quantity of NO3-ions (the chemical formula of nitrates) in this case too, which must be shown on the bottle label.
How to avoid nitrates and nitrites
Additives, fruit, vegetables, drinking water… There is no doubt that, given the different food sources, it is not easy to keep nitrate intake under control. Here are some rules that allow you to limit its assimilation.
• Do not heat foods containing nitrates, as they are transformed into nitrites more quickly with heat.
• Always give ample space on the table to fruit rich in vitamin C: various studies indicate that it hinders the formation of nitrosamines.
• Prefer seasonal vegetables to those grown in greenhouses.
• In green leafy vegetables, remove the outer leaves (the richest in nitrates).
• Consume the vegetables richest in nitrates in the short term because over time they are transformed into nitrites anyway.
• For raw ham, prefer DOP ham (for example Parma and San Daniele) because nitrates and nitrites cannot be added.
• Preferably choose organic products or integrated agriculture.
• Do not consume more than 150 g of processed meats and sausages (with nitrates and nitrites) per week.
• Choose mineral waters that have a minimum nitrate content (ideally below 10 mg/l).
You can also measure them
On the net it is possible to buy practical testers, that is, devices for instantaneous reading of nitrates, nitrites and radiations present in foods.