- Aluminum - properties and application
- Aluminum - he alth impact. Is aluminum harmful?
- Aluminum - sources in food and more
- Are aluminum pots harmful? Is aluminum foil he althy?
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Due to its properties, aluminum has been widely used. It is used to produce pots, lids, trays, cans and films that come into contact with food. Is cooking in aluminum pots, baking in aluminum foil or grilling in aluminum trays harmful to your he alth? Check the he alth impact of aluminum.
Aluminum , or actually aluminum, is a chemical element from the group of metals with the symbol Al, which was discovered in 1825. It is a solid, silvery-white, blue-tinged, malleable and malleable substance. It is one of the best conductors of electricity and heat. Aluminum is perfect for welding, gluing, riveting, casting, enamelling, drawing into pipes and thin wires, as well as forming into very thin foils.
Aluminum - properties and application
Aluminum, thanks to its physical and chemical properties, is widely used. Its low density, good plasticity ( although pure crystalline aluminum is brittle and brittle) and rust resistance are especially appreciated.
It is common to use aluminum alloys with other metals: duralumin, avional, silumin, especially in the construction industry (reducing the weight of steel structures) and automotive (car bodies, engines, rims), in the production of ships, airplanes (aluminum accounts for approx. 80% of their mass and, unlike steel, does not corrode) and space shuttles.
Aluminum is used in the chemical industry, in mining for the production of explosives, it is used to make cans and thin films as food packaging.
Aluminum compounds are used in medicine - aluminum hydroxide in hyperacidity and stomach ulcers, and aluminum sulphate for staunching bleeding. The industries in which aluminum products are used are:
- construction - aluminum joinery, roofing, facades, heating, air-conditioning, insulation
- communication - automotive components, vehicles, shipbuilding, railway, infrastructure
- electrical engineering - lighting, electrical appliances, antennas, RTV equipment
- machine building - cooling counters, air conditioning, tanks, dryers, metal accessories
- packaging - caps, disposable packaging, trays, cans, foils
- Household appliances - pans, kettles, pots,refrigerators, hoods
Aluminum - he alth impact. Is aluminum harmful?
Aluminum accumulates in the human body with age. In the bodies of newborns it is on average 0.2 mg / kg body weight, while in the elderly - 0.6-0.7 mg / kg body weight.
An adult's body accumulates from 50 to 150 mg of aluminum, 50% of which is in the lungs, 25% in bones and joints, and the remaining 25% in soft tissues. Aluminum accumulates in tissues because its Al3 + ions are very similar in size to iron Fe3 + ions and thus they can substitute for iron in various proteins or enzymes.
After passing through the mucosa, aluminum becomes part of the transferrin protein (transporting iron ions), which is absorbed by every cell in the body. Inside the cells, transferrin releases the bound ion and returns to circulation. This is how aluminum ends up in the brain, lungs, bones and other tissues.
Aluminum is an element that is toxic to the human body. This relationship is particularly visible among dialysis patients, because the equipment used for dialysis does not remove aluminum ions from the plasma as effectively as the kidneys.
People undergoing dialysis suffer from impaired coordination of movements, muscle tremors, involuntary movements or dementia, which occurs even 15 months after starting dialysis. The toxic effects of aluminum mainly affect the nervous, skeletal and blood systems.
The main symptoms of aluminum poisoning include:
- impaired intellectual functions
- forgetting
- problems with concentration
- speech disorder
- personality changes
- changeable mood
- depression
- dementia
- visual and auditory hallucinations
- osteomalacia and more frequent bone fractures
- motor disorders
- weakness, fatigue
- anemia
- seizures
Aluminum crosses the blood-brain barrier and accumulates especially in the hippocampus. This is responsible for conditions such as amyotrophic lateral sclerosis, senile dementia, Parkinson's disease, and to some extent Alzheimer's disease.
The brains of people who died in old age suffering from neurodegenerative diseases show a higher concentration of aluminum ions than in people who died from other causes. Moreover, epidemiological studies show a directly proportional relationship between the aluminum content in the environment and the number of people suffering from senile dementia.
Aluminum - sources in food and more
Plant foods are important sources of aluminum in the diet. This element is accumulated invegetables, fruits and cereals. Plants collect it mainly from the soil through the roots, but also from rainfall and atmospheric dust. A certain amount of aluminum is necessary for plant growth.
The concentration of aluminum is significantly dependent on the environment, species, part of the plant and stage of development. The older and more mature the plant, the higher the concentration of aluminum in its tissues. Most plants accumulate less than 25 μg of aluminum per gram of dry weight of the product.
Legumes (beans, peas, soybeans, lentils, chickpeas), spices such as thyme and marjoram accumulate a lot of aluminum, and its main source in the diet is tea, which grows on acidic soils and accumulates in leaves from 500 to 20,000 ppm aluminum. Most of the aluminum in tea, however, is in the form of a water-insoluble s alt and small amounts of 2 to 6 mg / l are added to the infusion.
The transfer of aluminum ions to the brew is increased by lowering the pH of the solution by adding lemon or citric acid. Then the acid reacts with aluminum s alts and the metal ions migrate. In animal products, the aluminum content is very low, usually below 1 μg / g dry weight.
An exception is Swiss cheese (19 μg / g dry weight). The amount of aluminum can also be increased in milk and dairy products, which is related to the storage of milk in aluminum tanks during the production process.
The amount of this element may raise concerns related to he alth risk. When buying milk, it is better to choose those in plastic packaging than cardboard coated with a layer of aluminum foil. It is also recommended to use steel tanks in dairies instead of aluminum ones.
It should be noted, however, that phosphorus compounds present in milk reduce the absorption of aluminum. Due to the increased aluminum content in surface waters, the accumulation in fish and seafood is also increasing.
Not only food is the source of aluminum accumulating in the human body. It is a component of everyday hygiene products and some medications. Due to its very wide distribution in nature, it is impossible to completely avoid aluminum. This element is delivered to the body through:
- tea infusions (2 - 6 mg / l)
- coffee (0.8 - 1.2 mg / cup)
- drinking water (0.07 mg / l)
- drinks in aluminum cans (0.04 - 1.0 mg / l)
- cooked spinach (25 mg / kg)
- unprocessed food (0.1 - 7 mg / kg)
- food additives (10-20 mg / day)
- food cooked in aluminum pots (0.2 - 125 mg / kg)
- mixturessoy-based milk replacers (6 - 11 mg / kg)
- Antacids (35 - 200 mg / dose)
- aspirin (9 - 50 mg / dose)
- anti-diarrheal drugs (36 - 1450 mg / dose)
- antiperspirants (50 - 75 mg / day)
- vaccines (0.15 - 0.85 mg / dose)
Aluminum - food additives containing aluminum
The approved additives containing aluminum in food are:
- E 520 - aluminum sulphate, binder
- E 521 - sodium - aluminum sulphate, acidity regulator, binder
- E 522 - potassium aluminum sulphate, acidity regulator, binder
- E 523 - aluminum ammonium sulphate, acidity regulator
- E 541 (I, II) - sodium-aluminum phosphates (acidic and basic), raising agent
- E 554 - sodium aluminosilicate, anti-caking agent
- E 555 - potassium aluminosilicate, anti-caking agent, carrier
- E 556 - calcium aluminosilicate, anti-caking agent
- E 559 - aluminum silicate, anti-caking agent, carrier
Aluminum compounds are used in candied, crystallized and frosted fruit, biscuit products, spice mixes, grated cheeses, sliced cheeses, confectionery except chocolate, chewing gum, sausages, dried and powdered foods.
Estimated consumption of aluminum-containing food additives in Europe ranges from 2.3 to 145.9 mg / kg body weight / week depending on the country and age group. Their highest consumption is observed among children.
Are aluminum pots harmful? Is aluminum foil he althy?
Aluminum gets into the human body mainly through the alimentary route, along with water, food, medicines, and as a result of the use of aluminum packages and dishes. The penetration of aluminum into food depends on the type of aluminum from which the packaging or vessel is made, the degree of acidity of the food, the time of contact with the food and the presence of s alt. The lower the pH of the food and the longer the cooking or storage time, the more aluminum ions penetrate into the food.
Migration of aluminum from aluminum to food [Zuziak J. et al., 2016]
The World He alth Organization (WHO) has established a safe daily aluminum intake of 1 mg / kg of body weight, which means that an average person weighing 70 kg can safely provide 70 mg of aluminum per day to the body without worrying about he alth. In order not to exceed the recommended dose, it is necessary to use appropriate utensils while cooking and avoid eating any foodstored for a long time in metal packages.
Cooking in aluminum pots, baking in aluminum foil or grilling in aluminum trays increases the amount of this element in the diet and can be dangerous to your he alth. You should especially pay attention to acidic products stored in cans, e.g. fish in tomato sauce, cola, and cooking food with a low pH such as apples, pears, blueberries, currants, raspberries, cherries, grapes, grapefruits, beets in vinegar, ketchup, lemon, lemon juice, peaches, nectarines, pineapple, plums, pomegranate, rhubarb, sauerkraut, strawberries, tomatoes and tomato preserves, vinegar, fruit juices, dry wine.
Also, do not wrap acidic vegetables and fruits in aluminum foil, as this causes the aluminum s alt to dissolve and penetrate into the food. It is also better to avoid drinks and food in aluminum cans as they can be stored for a very long time and time promotes increased accumulation of aluminum in drinks and food. The aluminum content of beverages from aluminum cans is 5 to 7 times higher than that of the same beverages made from plastic bottles.
Aluminum in chemical terms is an element in the 13th group of the periodic table, usually occurring in chemical compounds with a +3 oxidation state. This metal is covered with a thin layer of aluminum oxide in the air (it becomes passivated), preventing further oxidation and corrosion. The layer covering the metal is resistant to water and weak acids, but it is destroyed by strong acids and bases. Aluminum oxide and aluminum hydroxide are amphoteric compounds - they can react with both acidic and basic substances.
Aluminum is one of the main components of the earth's crust (7-8%) after oxygen and silicon. It does not exist in the free state because it is very reactive, and its compounds are present in almost all rocks, waters and living organisms. Most of the aluminum compounds in nature are sparingly soluble substances, but some show properties that are toxic to organisms.
Toxic compounds are released from harmless ones in an acidic environment, therefore the acidification process of soils increases the concentration of harmful forms of aluminum in nature - in soils and surface waters. Aluminum in the form of dust is present in the air. It is also accumulated by plants from soil, rainfall and air. It occurs in trace amounts in the organisms of animals.
Aluminum on an industrial scale is obtained by electrolysis of alumina, while this is obtained from bauxitethe German Bayer alkaline method or the Polish Bretsznajder acid method. The pure aluminum content in bauxites is high and amounts to 20-30%. The largest producers of bauxite in the world are Australia, China and Brazil. Annually, a total of about 60 million tons of aluminum oxide are obtained, while pure primary aluminum - about 25 million tons.
Products made of aluminum are often recycled, which extends the life cycle of the raw material. This material is relatively easy to recycle, which is why it is referred to as "green metal". Annually, about 15 million tons of aluminum are recovered from separate waste collection.
Sources:
1. Zuziak J. et al., Environmental aluminum and its influence on living organisms, Analit, 2016, 2, 110-120
2. Crisponi G. et al., The meaning of aluminum exposure on human he alth and aluminum -related diseases, Biomolecular concepts, 2013, 4 (1), 77-87
3. Michalski B., University of Wrocław, Aluminum market, https://www.ism.uni.wroc.pl/sites/ ism / art / michalski_rynek_aluminium.pdf
4. Kossakowski P., Aluminum - ecological material, Przegląd Budowlany, 2013, 10, 36-41
5. https://www.clemson.edu/ extension / food / food2market / documents / ph_of_common_foods.pdf
6. https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/sp.efsa.2013.EN-411
Aleksandra Żyłowska-Mharrab, dietician Food technologist, dietitian, educator. A graduate of Biotechnology at the Gdańsk University of Technology and Nutritional Services at the Maritime University. A supporter of simple, he althy cuisine and conscious choices in everyday nutrition. My main interests include building permanent changes in eating habits and individually composing a diet according to the body's needs. Because the same thing is not he althy for everyone! I believe that nutritional education is very important, both for children and adults. I focus my activities on spreading knowledge about nutrition, analyze new research results, and make my own conclusions. I adhere to the principle that a diet is a lifestyle, not strict adherence to meals on a sheet of paper. There is always room for delicious pleasures in he althy and conscious eating.
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