Zinc - impact, sources & use

In addition to iron, zinc is the second most common trace element in the human body. Around 70% of the body’s zinc content is found in bones, skin and hair. The other 30% are primarily distributed across the liver, kidneys and muscles. However, high concentrations are also found in the retina and iris of the eyes as well as in the male reproductive organs.

The body of an adult contains about 2 to 4 grams of zinc. These are relatively small amounts - hence the designation as a trace element. However, in order for the more than 300 zinc-dependent enzymes to function and the reactions involving them to run smoothly, the body must always have sufficient zinc available.

In contrast, there are two challenges: On the one hand, the human body can only store zinc briefly and in small quantities. On the other hand, the body cannot produce zinc itself. The necessary replenishment can therefore only be made from the outside  – via food and, if necessary, also via nutritional supplements. The high strategic importance of zinc results from the wide range of processes that rely on zinc.

Whether skin, hair nails, eyesight, immune system or bones, a good zinc supply supports their normal function. Cell division, protein production and fertility are also dependent on a good zinc supply. But why does the trace element have its hands in play in so many processes?

The background is that the trace element in our body is an important component or activator of countless enzymes – these are important reaction accelerators in our metabolic processes. They can only do their job smoothly if there is enough zinc.

To a certain extent, the healthy human adult body is able to regulate zinc absorption automatically. If the need for zinc in the body increases due to specific stresses or during specific life situations, the body changes the way it deals with the food it receives. In these cases, it removes a correspondingly higher amount of the trace element from the food and eliminates less.

This allows the body to regulate its zinc balance over several days. But as with everything in life, this effect also reaches its limits at some point – for example, if the food you eat does not contain enough zinc or the increased requirement lasts for a longer period of time.

First of all: everyone needs zinc. However, some groups of people should pay particular attention to the trace element. These include pregnant and breastfeeding women, as well as people who sweat a lot. Adequate zinc supply is also an important topic for children and adolescents. According to D-A-CH reference values, 10-year-olds already have the same zinc requirements as adult women (8 mg per day) – the trace element is essential for growth. Stress, infections or chronic diseases can also have an additional effect on the body’s zinc status. Likewise, the trace element with its numerous functions is particularly important in times of increased pressure, e.g. when you are under stress or undertaking sporting challenges.

Zinc uptake is highly dependent on phytate intake. Phytates are secondary plant substances that are always part of a diet rich in whole grains – they are often found in whole grains and legumes, for example. Phytates bind zinc to the gastrointestinal tract so that it can no longer be absorbed by the body. Accordingly, the diet has an effect on zinc requirements: high zinc absorption is present in diets where consumption of whole grain products and legumes is low and protein sources are primarily of animal origin. Absorption is reduced in diets where the consumption of whole grain products (mainly non-sprouted or unfermented) and legumes is high and the protein sources are primarily or exclusively of plant origin (e.g. soy) – the zinc intake should be correspondingly highest.

The following also applies: men and women are different when it comes to zinc. While women are advised to take 7-10 mg zinc per day depending on the amount of phytate intake, men in the same age group are advised to take 11-16 mg of zinc daily. However, this may be a little more for pregnant or breastfeeding women: in this special phase of life, the daily zinc requirement increases to 11-14 mg.

90% of zinc is present in red blood cells in the blood. In the event of insufficient supply, the body tries to keep the zinc concentration in the blood serum (= liquid part of the blood) stable for as long as possible. Zinc is removed from the red blood cells in which zinc depletion can be detected. To determine the zinc status, a whole blood analysis is therefore particularly recommended. In contrast to so-called serum diagnostics, it also includes red blood cells.

Good zinc sources include meat, offal, oysters, dairy products, eggs and fish. Plant-based zinc sources are less well utilised for various reasons (mainly due to the inhibitory phytic acid), which is why the aspect of zinc should be kept in mind, especially with vegetarian and vegan diets. Plant-based sources of zinc include spinach, oats, wholegrain products and wheat germ, pulses and nuts. For grain products, it must be ensured that the zinc content is high, especially in the husk and just underneath it. The zinc content of grain products therefore depends on their degree of milling.

Zinc is a building block and activator of numerous enzymes that contributes to the maintenance of many biological processes. Since the body lacks significant zinc stores and cannot produce it itself, the trace element must be fed regularly from the outside. If necessary, nutritional supplements can also be used for this.

When should you take zinc?

For optimal absorption, it is recommended to take between meals. Experience from practice shows that zinc tolerance depends on the daily rhythm. Therefore, it is recommended that sensitive patients take zinc in the evening or take it with meals.

High doses of zinc interfere with the absorption of iron, copper, calcium and selenium. Therefore, a time-delayed intake of mineral supplements at intervals of at least two hours is advisable.

Zinc for children

In order for children to grow and thrive smoothly, their cells must be able to divide “like clockwork”. This is where zinc comes in, which supports the normal growth of children and adolescents through its function in cell division.