Should we be concerned about the amounts of additives in our diet?
Food additives are a group of substances with next to nothing in common. Some of them are simple salts such as sodium phosphate (E339) or substances also used in cooking such as acetic acid (E260, vinegar). At the other end of the spectrum are nutritionally completely useless substances such as synthetic food colours. For brevity, all food additives in Europe have been given an E-number, and their presence is listed on food packaging by this E number or by their chemical name.
Authorities have to approve the additives following similar rules as are used for drugs. This guarantees that toxicological basic information exists, and generally there is some kind of international risk assessment before acceptance. This is the way it should be, because food is one of our most important amenities as well as prerequisite of life. Therefore it should be safe. At the same time it is best to remember that there are hundreds of thousands of substances in our food, most of which have not been fully characterised or tested. Therefore the food itself poses in principle a far higher risk than the additives.
In the European Union, the responsible authority is European Food Safety Authority (EFSA). EFSA carries out safety evaluations of new food additives before they can be authorised for use in the EU. EFSA has also begun to carry out a systematic re-evaluation of all authorised food additives in the EU. In the United States, the corresponding authority is Food and Drug Administration (FDA).
Preservatives such as benzoic acid (E210), sorbic acid (E200) and nitrite (E250) are important for the safety of food, because they prevent spoilage of food by microbes and also the production of potent microbial toxins such as botulinum toxin in the products. Therefore both benefits and risks have to be considered and assessed. If there is a need to store the food for more than one or two days, it is not sensible to run the risks of spoilage that are usually much greater than the risks associated with preservatives. For example, sorbic acid is present in many natural products, especially in well keeping berries such as cranberries and rowanberries (rowan belongs to Sorbus family, hence the name sorbic acid). Likewise, nitrites are naturally obtained from our vegetables.
Therefore the important point is the concentration, not simply the presence, of these compounds. On the other hand one is also justified to question the use of preservatives merely to increase the shelf life of products. For example, one could argue that one should be able to see if bakery products are old and stale.
In a way the least useful group of the food additives is the food colourings. They are most abundant in manufactured products such as cola drinks, dark beer, jellies and confectionery. Many colours are natural colours such as carotene (E160a) and chlorophyll (E140). Synthetic colours are usually not absorbed, and they have been thoroughly studied. Probably the azo dyes are the most problematic, and they may cause symptoms resembling allergies, but usually immunological mechanisms are not involved. There have been claims that azo dyes are associated with ADHD-syndrome (hyperactivity syndrome of children). On the other hand, it has been said that the association has been studied at doses that are not relevant. The jury is still out here, but the case does not seem to be very strong.
The intake levels of food additives are quite variable in different countries and different cultures. Clearly high consumption of ready-made foods and preserves increases the intake, and conversely intake is low if food is made at home from simple basic raw materials such as meat, fish, milk, eggs, flour and potatoes. This means that the individual has a clear possibility to avoid additives, if he/she is worried. On the other hand, if one accepts the convenience of ready-made foods and preserves, then it is far better to run the minor potential risks of additives rather than to run the far higher risks of spoilage.
Usually the intakes of benzoic acid and nitrite are closest to the acceptable daily intake (ADI) levels of all additives. Their intake depends to a great extent on the consumption of preserves. Fruit and berry preserves may contain benzoic acid, and preserved meat such as sausages are high in nitrite. In individuals consuming plenty of these foodstuffs, then the intake values may be high as compared with the ADI level.
The ADI levels always include significant safety margins. Therefore exceeding these limits does not necessarily translate into adverse effects, but continuous consumption in excess of recommendations should be avoided. This is best done by eating a variety of foods and avoiding excessive use of any single kind of product. This is most problematic with youngsters who tend to stick to fashionable fast-foods that cannot be recommended because of many other reasons. They are often also very salty and fatty. As is the case with sugar as well, our human ancestors lived in a wilderness and did not develop good protection against fat and salt. These materials used to be in short supply and therefore it was always beneficial to consume all of the fat, sugar and salt available. This preference is in our genes now, even if it does not serve any useful purpose in the present society of plenty.
In fact, salt is our most problematic food additive, even if it is not included by the authorities in most countries in the category of food additives. It is an essential mineral, but the need is far lower than the present intake. Salt has been clearly shown to increase blood pressure, and this is important in the development of serious cardiovascular diseases. Very high intakes are also associated with cancer of the gastrointestinal tract. If there were as strong evidence about the adverse effects of any food colour, it would be immediately banned. In fact, salt, which is outside the list of additives, does enjoy special status. Any other food preservative with such clear side effects would probably be prohibited. Also sugar, which is today a sweetening agent rather than a nutrient, is responsible for causing serious health problems.
Another problematic group is poorly controlled energy and vitamin supplements and even hormones sold for instance in supplements for body building and exercise. These may cause risks even when within legal limits, to say nothing of the illegal trade.
When the safety of food additives is considered, both the benefits and the risks of the substances must be carefully taken into account. The greatest health risks may arise from the most surprising sources, e.g. common salt is a much more harmful compound than benzoic acid though both are food preservatives.
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