Biological medicine warns of the consequences of consuming some of these generally harmless substances, which are added to food to preserve its freshness, taste or appearance.

The food additives are not exclusive to the contemporary age. Keeping food in good condition has been a human concern since ancient times. The use of salting and smoking as preservation techniques dates back thousands of years. The Egyptians also used colourings and flavourings to enhance certain foods and the Romans used brine, spices and colourings in their preserves and preparations.

Thus, if we take into account the definition given by the World Health Organisation (WHO) the food additives are "substances added to food to maintain or improve its safety, freshness, taste, texture or appearance". For example, antioxidants, which are added to prevent or retard food spoilage due to oxidation. This deterioration affects not only their appearance, but also their nutritional properties, which are lost due to the evaporation of vitamins A and C. In addition, an unpleasant taste, "rancidity" (a consequence of the deterioration of fats), as well as elements that are harmful to health are often generated.

But how does oxidation occur? Before we can detect with the naked eye that a food is oxidising, there is a so-called latency period, in which the fats in the food catch the ultraviolet rays of light or simply heat, forming free radicals from the fatty acids. These free radicals accelerate the oxidation processThe process continues as long as there are fats that can oxidise. The process continues as long as there are fats that can oxidise, producing, in turn, substances that generate the rancid smell characteristic of oxidised foods. This is the termination process.

Substances accelerating the oxidation process

In addition, there are a number of substances that accelerate or facilitate the oxidation process. These are the pro-oxidant factors, such as:

• The degree of unsaturation of fatsThe less saturated they are, the easier it is for them to take up oxygen.
• Oxygen pressureThe higher the concentration of oxygen in the air in contact with the food, the easier and quicker it is to bind to fats.
• Heat: The higher the ambient temperature of the food, the more it will oxidise (hence the importance of refrigerators to keep food at a lower temperature).
• Light
• Ionising radiation
• Pigments: especially chlorophyll, cytochrome and myoglobin
• Enzymes: especially lipases and lipooxygenases.
• Heavy metals: in particular cadmium, mercury and lead, although the presence of copper and iron also accelerates oxidation.

To prevent oxidation, on the one hand, the following can be tried reducing or eliminating all these pro-oxidant factorsor adding substances to food that slow down or prevent this process. These are the antioxidant additives themselves. The food industry uses both techniques, i.e. in addition to hydrogenation and fat saturation, vacuum and light-tight packaging, eliminating metal residues from the machinery used and storing the products in cold stores, it also uses antioxidants authorised by the health authorities.

These additives must be safe for health and to maintain the characteristics of the food. In this regard, it is essential that they are stable, according to the pH of the product to which they are added, so that they do not undergo chemical reactions that prevent their function. Also, remember that antioxidants do not last forever. When they become saturated, they no longer capture free radicals and are no longer effective, so the oxidation process continues.

The citric acid (of bacterial origin and found in soups, ice cream or frozen fish and seafood), the ascorbic acid (very common in fruit drinks, jams or dehydrated potato derivatives), the lactic acid (present in baby food, carbonated beverages or light margarines), the lecithin (whose origin is in soy, corn or peanuts and which can be found on the label of cream desserts, liquid yoghurts, milk powder or margarine) or the tocopherols (present in prepared desserts or vegetable oils) are examples of antioxidant additives.

Antioxidant additives under suspicion

Additives can be natural or synthetic and not all additives are suitable for all types of food. For example, there are some additives that cannot be used in the processing of foods with high temperature stages such as bakery products. Moreover, although the list of authorised antioxidant additives is extensive, some additives are under suspicion.

The following are examples of additives whose adverse effects are reported - and remain authorised as long as they are considered safe by health authorities.

- E 302: May cause kidney stones in people with a tendency to kidney stones.
- E 310: According to a study published in 1981, it may be carcinogenic.
- E 311: According to a study published in 1981, it may be carcinogenic.
- E 312: According to a study published in 1981, it may be carcinogenic.
- E 320 and E 321: Allergisers. They accumulate in the body. May cause liver cancer. Damaging to the kidneys. Potentially carcinogenic. According to WHO, E 321 can cause growth retardation and reproductive impairment. Banned in Japan and other countries.
- E 330, E 331, E 332, E 333 and E 380: May cause oedema and urticaria. They may erode teeth and cause ulcers in the oral mucosa. E 330 appears to be carcinogenic.
- E 338, E 339, E 340 and E 341: In high amounts can cause osteoporosis in children. They cause kidney disorders and stones. May cause concentration disturbances. E 338 appears to be carcinogenic.
- E 385: Potent metal scavenger. May have carcinogenic effects.

Antioxidants and Biological Medicine

The most common today are those of chemical synthesis, which mimic the composition of the original substance. However, there are also natural and artificial (fully synthetic) ones. They are usually safe and do not produce negative health effects, unless you are allergic to any of them or ingestion of doses above the recommended levels. However, the biological medicine disagrees with this total innocuousness which these substances are known for. In this respect, the head of BiosaludDr. Mariano Bueno, referring to various published studies, refers to the possible effects of some of them. He points out that calcium ascorbate (E-302) can lead to kidney stones in people with a tendency to do so or that propyl gallate (E-310), octyl gallate (E-311) and dodecyl gallate (E-312) could be carcinogens.

Other antioxidants with possible side effects are butylated hydroxyanisole (E-320) and butylated hydroxytoluene (E-321), since they are allergens and accumulate in the body. They are harmful to the kidneys and are potentially carcinogens. In fact, according to the WHO, E-321 can cause growth retardation and reproductive impairment. Citric acid (E-330), sodium citrate (E-331), potassium citrate (E-332), and calcium citrate (E-333) can cause enemas and hivesas well as erode teeth and cause ulcers in the oral mucosa.

For all these reasons, and when in doubt, Biosalud recommends avoiding these antioxidants as far as possible. The easiest way to do this is check labels before purchase or consumption certain foods or beverages.