Dr. med. Heinz Lüscher
The trace element zinc is a jack-of-all-trades; it plays a central role in numerous processes and functions in the human body. With the right supply, it makes the organism more resistant and efficient. It supports the immune system, counteracts inflammation and infections, improves skin function and wound healing and ensures normal hair growth. Zinc also has an influence on the hormone system, but that is by no means all.
Zinc in the daily diet
Zinc is the second most common essential trace element in the body after iron; this means that although it is only needed in trace amounts, it is vital and cannot be produced by the body itself. The body can hardly store it, which is why a continuous intake via the diet is important. Zinc is found in many foods, such as meat (especially liver), fish and seafood (in high quantities in oysters), certain types of cheese (e.g. Emmental), pulses (e.g. soybeans), oat flakes and certain seeds and kernels. The absorption of zinc can be inhibited by the simultaneous intake of calcium, iron or copper as well as tannins (tannins). Phytic acid, which is contained in cereals and pulses, for example, binds zinc and forms insoluble zinc-calcium-phytate complexes, making zinc less easily absorbed in the intestine. High concentrations of mustard oil glycosides (or glucosinolates), which are contained in plants such as radish, mustard, cress or cabbage, also lead to the formation of complexes with zinc. For these reasons, zinc is generally more bioavailable from animal foods than from plant foods, as animal foods do not contain any of these absorption-inhibiting substances. However, it is also known that phytic acid is broken down when cereals, pulses or oilseeds sprout (even after prolonged soaking in water, e.g. overnight), thus increasing the bioavailability of minerals and trace elements, including zinc. People with a vegetarian or vegan lifestyle should pay particular attention to this. Zinc absorption is also promoted in combination with vitamin C.
Effect in the body
Zinc is contained in numerous enzymes (“accelerators” of biochemical reactions) and other proteins in the human body. The trace element activates around 200 different proteins, which are responsible for important functions of enzymes and hormones. Zinc content is particularly high in the pancreas and testicles, as zinc is used to store insulin and produce testosterone. It also has an effect on thyroid and growth hormones. It is also necessary for the metabolism of carbohydrates and fats and plays a role in cell growth (e.g. skin, mucous membranes, hair, nails), fertility and the immune response. It is well documented, for example, that zinc can reduce the duration and severity of colds. It acts in the first line of defense of the immune system (innate immunity), which fends off pathogens. It also acts as an antioxidant that can curb the damage caused by free radicals, for example during an inflammatory reaction. An optimal zinc level can therefore help the body to defend itself more effectively against infectious diseases as well as autoimmune diseases, chronic inflammation and allergies.
The symptoms of a deficiency can be very far-reaching due to the diverse effects of zinc. Problems and changes often appear in the skin, hair or nails. Deficiency symptoms can manifest themselves in dry, flaky skin, wound healing disorders and inflammatory skin diseases such as acne or eczema, and susceptibility to skin or nail fungal infections is also possible. Brittle nails or hair loss can also be associated with a zinc deficiency. Zinc deficiency can lead to serious hair loss, especially in people with hypothyroidism (underactive thyroid). This is because zinc (together with other trace elements) is essential for the synthesis of thyroid hormones. A lack of zinc can even promote hypothyroidism and, conversely, a lack of thyroid hormones can lead to zinc deficiency in the case of existing hypothyroidism. Zinc deficiency can also lead to fertility or growth disorders, tiredness and states of exhaustion and immunodeficiency.
Indications for zinc supplementation
- Zinc deficiency (e.g. chronic intestinal diseases, stress, infections, vegetarian or vegan lifestyle)
- increased requirement (e.g. pregnant women, breastfeeding mothers, menopause)
- Hair loss
- Problems with fertility
- Hypothyroidism, Hashimoto’s thyroiditis
- Autoimmune diseases
- Promotion of wound healing
- Skin diseases such as acne or eczema
- Wilson’s disease (copper storage disease)
I recommend a zinc preparation in liquid form (drops), which has the advantage that it can be optimally dosed. Zinc is usually administered in the form of zinc sulphate, which has a high bioavailability and is used as the standard in most clinical studies. By adding the amino acid L-histidine, a zinc-histidine complex is formed, which is even more bioavailable and is the most extensively studied form of zinc. Various authorities recommend zinc-histidine as a source of zinc, especially for children.
The advantage of zinc-histidine is that it can prevent the above-mentioned complex formation with e.g. phytic acid. In this case, the zinc already forms a complex with the L-histidine during production and is therefore to a certain extent no longer available for complex formation with phythic acid. In contrast to the zinc-phytic acid complex, however, the zinc-histidine complex is dissolved again in the intestine, the zinc can be absorbed immediately and bioavailability is guaranteed. The zinc-histidine complex keeps the zinc in a dissolved, absorbable form even in the presence of phytates, mustard oil glycosides or tannins and can therefore be taken with food. Accordingly, such a product is also better tolerated than zinc sulphate, which must be taken on an empty stomach (to prevent irreversible complex formation), which can lead to discomfort or even nausea in many people.
10 to 25 mg per day, depending on the area of application and requirements.
If the dosage is (too) high, zinc histidine is excreted renally (via the kidneys, i.e. via the urine), which rules out an overdose.
An American study from 2015 showed that zinc intake in doses of ≥ 75 mg/day shortened the duration of symptoms and significantly reduced the severity of colds. The study was conducted in otherwise healthy subjects who had no secondary diseases. https://pubmed.ncbi.nlm.nih.gov/25924708/
Zinc deficiency associated with hypothyroidism: An overlooked cause of severe alopecia (hair loss): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746228/
Histidine-zinc complex – An optimized way of substitution (Deutsche Apotheker-Zeitung): https://www.deutsche-apotheker-zeitung.de/daz-az/2000/daz-5-2000/uid-6223#:~:text=Histidine%20improves%20the%20resorption%20and,albumin%20%5B85%2D89%5D