Trace Elements


Various minerals are required by the body in only very small amounts; a few milligrams or micrograms are sufficient to fulfil the vital tasks. They are essential, however. These substances are known as trace elements and include:

– Iron
– Iodine
– Fluoride
– Zinc
– Copper
– Selenium
– Manganese
– Chromium
– Molybdenum


Iron

Functions in the body
Iron is a component of the red pigment of the blood (haemoglobin) and of the muscles (myoglobin). In haemoglobin it takes care of the transportation of oxygen into the blood. Many enzymes also require iron to fulfil their tasks; some take care of the transmission of energy, for example.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 10 (men) to 15 (women) mg of iron daily. The higher recommendation for women is due to the fact that women of childbearing age regularly lose blood – and thus also iron – through menstruation. Following the menopause, women do not need more iron than men.

Important food sources
The best food source of iron is meat. Here it occurs in a form that is particularly utilizable by the body, i.e. that is absorbable.

In addition, whole-grain products, legumes, nuts and some types of vegetables (e.g. varieties of cabbage) supply considerable amounts of iron. However, iron from plant foods cannot be assimilated as well by the body. Its usability can be improved by eating iron-rich foods together with foods rich in vitamin C. The vitamin C greatly increases the rate of absorption of iron. A fruit juice with muesli for breakfast or a mixture of iron-rich broccoli and vitamin-C-rich paprika, for instance, yields considerably more iron for the body than cereal or broccoli eaten without vitamin C.

Incidentally, the iron in spinach, which was formerly praised for it supposedly high iron content, is particularly poorly absorbed. Thus spinach is not exactly to be recommended as a supplier of iron.

Deficiency
Iron deficiency leads first to tiredness, fatigue and weakness of concentration. If it becomes more severe the result is anaemia.

Iron deficiency is rare in men. It is far more frequent as a result of menstrual blood loss in young girls and women. Iron deficiency during pregnancy is especially serious; this harms not only the mother-to-be, but also the foetus.

When anaemia has developed because of an iron deficiency, an iron-rich diet usually no longer helps to eliminate the deficit, and additional iron preparations are needed.


Iodine

Functions in the body
Without iodine, our thyroid gland cannot produce thyroid hormones. We need these, however, to control numerous important processes in the body. They have an influence on the entire metabolism and keep us going. Children, furthermore, need the thyroid hormones for their growth and their mental development.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 180–200 µg of iodine daily.

Important food sources
Most foods contain very little iodine in their natural state. The only meaningful source in our diet is saltwater fish. Since our consumption of fish is far from adequate to cover our iodine requirement, however, iodine has been added to table salt for quite some time ("iodised salt"). In the meantime, fortunately, a great number of people use this in the household. In addition, more and more iodised salt is being used as well in canteens, in food production and in the food industry.

One often reads that the use of iodised salt is dangerous and could lead to allergies or to a hyperthyroid condition. This is incorrect; iodised salt can be used without hesitation.

Deficiency
In spite of the fact that we require only minute amounts of iodine, not even a half milligram, iodine deficiency is widespread in Germany, mainly because now as before – with the exception of the coastal regions – we eat too little fish and iodised salt is still not used always and everywhere. In the past several years, however, a marked improvement has been noted in the supply situation through the increasing use of iodised salt.

Iodine deficiency leads to an enlargement of the thyroid gland and the formation of a goitre. These changes are due to the fact that the thyroid gland tries to compensate for the deficiency of iodine with the formation of more thyroid gland tissue, although this cannot eliminate the deficiency.

Other signs of an iodine deficiency are tiredness, weakness, less tolerance to cold and a gain in weight.

Children who suffer from an iodine deficiency experience disturbances of growth and development.


Fluoride

Functions in the body
Fluoride is a component of the bones and teeth. In the latter, it hardens the enamel and makes it more resistant to decay (caries).

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 3–4 mg of fluoride per day.

Important food sources
Most foods contain only small amounts of fluoride. Appreciable amounts are found only in fish and black tea. In some areas the drinking water also has a relatively high fluoride content.

For this reason iodised salt today is frequently also enriched with fluoride.

Deficiency
An inadequate supply of fluoride means an increased risk of tooth decay. However, since it is practically impossible to ensure a fluoride-rich diet, other measures of preventing decay are recommended. Thus infants should receive fluoride tablets, and fluoridated iodised salt should be used in the household, as well as toothpaste containing fluoride.


Zinc

Functions in the body
Zinc is important for the immune system. In addition, it is responsible for the storage of the hormone insulin and is a component of numerous enzymes.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 7–10 mg of zinc per day.

Important food sources
Zinc is contained in meat, innards, fish, eggs, milk and dairy products, and in whole-grain products.

Deficiency
Zinc deficiency is accompanied by changes to the skin (rash, loss of hair), by impaired wound healing, and by an increased susceptibility to infections, as well as by growth disturbances in children.

Owing to the widespread availability of zinc in our food a marked zinc deficiency is very rare. As animal foods especially are good sources of zinc, persons whose diet consists exclusively of plant foods are more prone to develop a zinc deficiency.


Copper

Functions in the body
Copper is a component of numerous enzymes, and it takes part in the metabolism of iron.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 1–1.5 mg of copper daily.

Important food sources
Good suppliers of copper are whole-grain cereal products, innards, fish, nuts and cocoa.

Deficiency
A pronounced deficiency of copper leads to anaemia, a disturbance of leucocyte formation, an increased susceptibility to bone fractures, and pigment aberrations of the skin and hair. However, copper deficiency is extremely rare.


Selenium

Functions in the body
Selenium is a building block of an enzyme that is responsible for the detoxification of free radicals. Selenium thus fulfils a very important task as an antioxidant.

Moreover, selenium is a component of several enzymes that are responsible for the formation of thyroid hormones.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 30–70 µg of selenium per day.

Important food sources
Selenium is taken in mainly with meat, fish and eggs. Lentils and asparagus are also good suppliers of selenium. In Germany the soil is relatively poor in selenium, and most plant foods, such as cereal products, are therefore not very rich in selenium.

Deficiency
Despite the fact that most foods contain only a little selenium, a nutritional selenium deficiency hardly ever occurs. At most persons with a very one-sided diet are at risk.


Manganese

Functions in the body
Manganese is necessary for the efficiency or activation of various enzymes that fulfil different tasks in the body.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 2–5 mg of manganese per day.

Important food sources
Plant foods usually contain more manganese than animal products. Some good suppliers are leeks, spinach, strawberries, oat flakes and tea.

Deficiency
Manganese deficiency practically never occurs.


Chromium

Functions in the body
Chromium carries out functions in the metabolism of carbohydrates.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 30–100 µg of chromium daily.

Important food sources
Chromium is contained in meat, liver, eggs, oat flakes, head lettuce, tomatoes and mushrooms, among other things.

Deficiency
Chromium deficiency practically never occurs.


Molybdenum

Functions in the body
Molybdenum is a component of several enzymes.

Recommended intake
According to the recommendations of the German Society for Nutrition, adults should take in approximately 50–100 µg of molybdenum daily.

Important food sources
Above all whole-grain products and legumes are rich in molybdenum.

Deficiency
Molybdenum deficiency practically never occurs.

 



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