Zinc is an essential trace element, which is important for the function of more than 300 enzymes. Especially the immune system, as the organ system with the highest proliferation rate, is extremely dependent on zinc homeostasis [1]. In all one third of the world population is at risk of zinc deficiency (ZD). ZD is common in developing countries, however in industrial countries like Germany up to 75% of seniors are at risk of ZD as well [2]. Since bioavailable zinc is mostly in fish and meat, people with vegetarian and vegan diet are at risk of ZD as well [3].

ZD seniors, vegetarians and vegans show a lower production of type I interferons after viral stimulation. Furthermore, the production of the major T cell cytokines interleukin-2 and interferon-γ is reduced as well. The production of these cytokines can be reconstituted by 10mg zinc supplementation over one to two weeks [4]. In elderly the overproduction of proinflammatory cytokines, called inflammaging, could be reduced as well [5].

Since there is currently no biomarker for ZD, the standard value is serum zinc measured by atomic absorption spectrometry or inductively coupled plasma mass spectrometry. However, serum zinc is influenced by hydration and current food intake. Furthermore, most serum markers are influenced by the way of blood drawing. Lastly, trace element measurement is missing mandatory round robin tests, which often results in low quality and reproducibility in clinical routine. Therefore, we established a food frequency questionnaire [6] as computer application www.zink-app.de [7]. As long as we do not have a biomarker, this application may be an alternative to zinc measurements for calculating the risk of ZD.

References
[1] I. Wessels et al. Ann. Rev. Nutr. 2021 41:133-175
[2] R.B. Baarz and L. Rink Ageing Res. Rev. 2022 74:101541 
[3] H. Schoofs et al. Molecules 2024. 29:3130
[4] R.B. Baarz et al. Immun. Ageing 2022 19:40
[5] L. Kahmann et al. Rejuv. Res.2008 11:227-237
[6] S. Trame et al. J. Trace Elem. Med. Biol. 2018 49:285-295
[7] S. Trame et al. J. Trace Elem. Med. Biol.2023 77:127132