Zinc – its importance for a dog's health
Zinc is an element essential for the proper functioning of a dog's body. This is due to its active role in many physiological processes, both as a component and an activator of numerous enzymes. It is involved in the metabolism of nucleic acids and carbohydrates, protein synthesis, and cell differentiation and division. It contributes to the proper functioning of the senses of taste and smell. It is important for growth and development. Without it, a dog's immune system could become significantly impaired. Zinc also supports skin regeneration and wound healing. It is also essential for the production of hormones such as testosterone, adrenal corticosteroids, and insulin. It is required for the enzyme-based antioxidant system, which limits the formation of reactive oxygen species. This is particularly important in sporting dogs.
How is zinc absorbed?
Zinc is absorbed mainly in the duodenum, jejunum, and ileum, with a small amount also absorbed in the stomach. The regulation of this process is not fully understood. It is known, however, to be linked to certain dietary components. Zinc absorption is reduced by phytates, which bind to the element and form insoluble complexes. They are found primarily in whole-grain products, legumes, nuts, and seeds (e.g. pumpkin seeds and flaxseed). Some compounds, on the other hand, enhance zinc absorption. These include citrates, picolinates, EDTA, and certain amino acids (e.g. glutamate and histidine). The liver is chiefly responsible for zinc metabolism. If zinc levels exceed physiological ranges, the excess binds to metallothionein, a protein believed to bind and store metals and to be involved in detoxification. Zinc is excreted in the feces and may comprise both unabsorbed zinc and zinc of endogenous origin (including zinc from pancreatic juice or bile).
Indicators of zinc status
A dog's zinc status can be assessed. Overall requirements are determined on the basis of zinc concentrations in the body, measured using biomarkers. However, selecting a biomarker with suitable sensitivity and the greatest possible specificity, while also being as minimally invasive as possible, is no easy task. Accurately determining a dog's requirements will certainly be useful when planning potential supplementation or dietary adjustments.
A zinc-rich diet
The main natural source of zinc is muscle meat, with beef being the richest and poultry containing considerably less. Liver has a lower zinc content. Zinc is also found in egg yolk and fish, including rainbow trout, salmon, and carp. Smaller amounts occur in plant foods such as rice, carrots, and apples. Water also supplies some zinc.
Does zinc come only from the diet?
Interestingly, in addition to the zinc supplied in a dog's food, the element can also enter the body through the respiratory tract. It has been detected at varying concentrations in household dust, which means that dogs may not only inhale it but also ingest it by licking different surfaces around the home.
Zinc and the BARF diet
Zinc deficiency is quite common in an improperly balanced BARF diet. When formulating a diet for a dog with zinc content in mind, it is advisable to consult a veterinarian and follow AAFCO recommendations. It should also be remembered that the bioavailability of zinc in commercial pet foods differs from that of zinc from natural sources in a homemade diet. For example, poultry studies found that the bioavailability of zinc from both raw and cooked meat was 40% higher than that of zinc supplied as zinc sulfate. Supplementation must also be approached cautiously to avoid a potentially dangerous overdose, which will be discussed in greater detail in the next article.
Sources:
- Wedekind, K. J., Yu, S., Kats, L., Paetau-Robinson, I., & Cowell, C. S. (2010). Micronutrients: Minerals and vitamins. W M. S. Hand, C. D. Thatcher, R. L. Remillard, P. Roudebush, & B. J. Novotny (Eds.), Small Animal Clinical Nutrition (5th ed., Chapter 6). Mark Morris Institute.
- Pereira, A. M., Maia, M. R. G., Fonseca, A. J. M., & Cabrita, A. R. J. (2021). Zinc in dog nutrition, health and disease: A review. Animals,** 11(4), Article 978. https://doi.org/10.3390/ani11040978
- Mirowski, A. (2013). Cynk w żywieniu psów i kotów. Część II. Wpływ rodzaju diety na zaopatrzenie w cynk. Życie** Weterynaryjne,** 88(6), 466–468.
- Mirowski, A. (2013). Cynk w żywieniu psów i kotów. Część III. Wskazania do suplementacji, naturalne źródła pokarmowe. Życie** Weterynaryjne,** 88(7), 569–572.