Zinc

Inhaltsstoff-Glossar

Zinc

What Is Zinc?

Zinc is a mineral and essential trace element that is required for the function of hundreds of enzymes. It is therefore indispensable for sexual health, immune function, brain function, and the body's antioxidant defense. Zinc supplementation is particularly popular for supporting the immune system during the common cold and for stimulating hormone production to promote muscle growth and strength.

Where Does Zinc Naturally Occur?

Zinc is a mineral found in the Earth's crust and is an essential trace element for the human body. Within the body, it is located primarily in muscles and bones, while less than 1% of the total body zinc is present in the bloodstream. As a result, blood zinc measurements are relatively imprecise, and there is likely a substantial number of people with undetected subclinical zinc deficiency.

Zinc is not a rare trace element. It is found in high concentrations in whole grains such as rye, wheat, oats, and rice; seeds including poppy, sesame, pumpkin, flax, and chia; legumes such as lentils and peas; cocoa; liver from wild game and pork; nuts; skeletal muscle meat; and cheese.

Most foods contain adequate amounts of zinc. The challenge therefore lies not only in choosing the right foods but also in combining them in a way that maximizes zinc absorption in the small intestine. Plant compounds such as phytic acid and polyphenols, as well as other minerals, can reduce zinc absorption. In contrast, fermentation, sprouting, or consuming fruits and vegetables together with a meal can improve zinc absorption to levels comparable to those achieved from animal-based foods.

In dietary supplements, zinc is available in various forms, including zinc oxide, zinc sulfate, zinc acetate, zinc chloride, zinc citrate, and zinc gluconate. However, organic zinc compounds such as zinc histidine are believed to offer the highest bioavailability.

What Is the Primary Function of Zinc in the Body?

Because zinc is a component of more than 300 enzymes, it ensures the proper functioning of nearly all vital processes in the body. Without zinc, only a small number of enzymes would be capable of catalyzing chemical reactions. It is involved in the metabolism of all three macronutrients: fats, carbohydrates, and proteins.

Zinc also plays essential roles in cell growth and immune function, including the regulation of excessive immune responses. As a structural component of zinc finger proteins, which belong to the family of transcription factors, zinc is also involved in the translation of genetic information within the cell nucleus.

According to the European Food Safety Authority (EFSA), zinc contributes to the maintenance of normal vision, normal acid-base metabolism, normal cognitive function, normal fertility and reproduction, healthy nails, hair and bones, healthy skin, and the protection of cells from oxidative stress.

What Are the Benefits of Zinc Supplementation?

According to the German Nutrition Society (DGE), the recommended daily zinc intake ranges from 11–16 mg for men and 7–10 mg for women. The exact recommendation depends, among other factors, on the phytic acid content of the overall diet. Because phytic acid can reduce zinc absorption, individuals consuming diets high in phytic acid should generally aim for the upper end of the recommended intake range. As a rule of thumb, the greater the consumption of whole grains, legumes, and plant-based protein sources, the higher the intake of phytic acid is likely to be.

Whether adequate zinc status is consistently achieved cannot always be determined with certainty, partly because of the influence of phytic acid and the limited reliability of individual zinc measurements in the body. An increased risk of inadequate zinc intake exists particularly among people consuming predominantly plant-based diets with a high phytic acid content. Young children, individuals with malabsorption syndromes, and people taking chelating agents, orlistat, laxatives, or proton pump inhibitors may also be at increased risk.

According to the German Federal Institute for Risk Assessment (BfR), there is a relevant risk of excessive zinc intake through dietary supplements, although not through conventional foods. This is due to the relatively small margin between the recommended intake and the tolerable upper intake level of 25 mg per day. Consequently, the BfR recommends a maximum daily zinc intake of only 6.5 mg from dietary supplements. For consumers, this means that the phytic acid content of the diet should be taken into account, while zinc supplementation should be approached with caution. In many cases, obtaining zinc primarily from natural food sources is the more prudent strategy.

Chronically high zinc intake through supplements may lead to adverse effects. Clinical studies have reported reduced white blood cell counts, impaired immune function, lower hematocrit values, and alterations in lipid metabolism with daily zinc intakes ranging from 50 to 300 mg. In addition, epidemiological studies have associated very high zinc intakes exceeding 75 mg per day with an increased risk of prostate cancer.

It is unlikely that zinc supplementation provides additional health benefits in individuals with an adequate zinc status. Positive effects of zinc supplementation have primarily been observed in studies involving insufficient dietary zinc intake, including improvements in acne, depressive symptoms, and blood lipid profiles. One frequently discussed exception is respiratory tract infections, where several meta-analyses have shown that zinc supplementation may shorten the duration of illness.

Zinc is essential for normal testicular function and male fertility. It also plays an important role in the body's production of male sex hormones. For this reason, zinc is commonly included in dietary supplements marketed to athletes and in products intended to support muscle growth. What is scientifically well established is that zinc deficiency can impair hormone synthesis and fertility, and that correcting such a deficiency may restore these processes. However, there is currently no convincing evidence that additional zinc supplementation increases male sex hormone levels in individuals who already have an adequate zinc status.

The central focus of current scientific research is therefore to determine under which health conditions and chronic diseases difficult-to-detect zinc deficiency may occur—and in which cases targeted zinc supplementation can provide meaningful health benefits.

References

Further information and scientific studies on the active ingredient zinc can be found here.

Zinc: An Essential Micronutrient
www.pubmed.ncbi.nlm.nih.gov/20141096

Bioavailability of Iron, Zinc, and Other Trace Minerals from Vegetarian Diets
www.pubmed.ncbi.nlm.nih.gov/12936958

A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models
www.ncbi.nlm.nih.gov/pmc/articles/PMC7146416

Dietary Factors Influencing Zinc Absorption
www.pubmed.ncbi.nlm.nih.gov/10801947

Revised D-A-CH Reference Values for Zinc Intake
www.pubmed.ncbi.nlm.nih.gov/32380426