Get all the zinc your body needs with plant-based foods

After iron, zinc is the most important trace element in the human body in terms of quantity. Due to its diverse functions, zinc plays a key role in numerous metabolic processes.

The function of zinc in our bodies

Zinc is involved in processes such as metabolizing protein, regulating the immune system, wound healing, and the maintenance of healthy vision.¹ Zinc also plays an important role in the stabilization of cell membranes, the production of sperm, alcohol detoxification, and the storage of insulin in the pancreas.^{2 3} Zinc is mainly found in our muscles and bones, but also in many of our organs (eyes, testicles, prostate).

Occurrence of zinc in plant-based food

Whole grains, pulses, oilseeds, and nuts are all good sources of zinc (see table below).⁴

Bioavailability of zinc

The bioavailability of zinc is higher in animal-based foods than it is in plant-based foods, and is influenced by the presence of various other nutrients. For example, the phytates contained in cereals and pulses (which can be broken down by sourdough fermentation or soaking and sprouting) and the oxalates contained in spinach and tea have a particularly inhibiting effect on zinc bioavailability.⁵
On the other hand, citric acid, which is contained in citrus and numerous other types of fruit, improves the availability of zinc from phytate-rich foods.⁶

How much zinc do our bodies need?

The daily recommendation for zinc intake is 11 mg for men and 8 mg for women.⁷

What are the signs of zinc deficiency?

A deficiency of zinc affects nearly all metabolic processes due to the diverse role it plays in the body. Symptoms of zinc deficiency include retarded growth, poor wound healing, loss of appetite, an impaired sense of smell and taste, impaired vision, immunodeficiency, impaired fertility, and changes in the skin and cornea.⁸

What are the causes of zinc deficiency?

The main causes of zinc deficiency are insufficient zinc intake through food, impaired zinc absorption in the intestine, and increased zinc excretion (e.g. due to kidney disease or alcoholism). While diet-related severe zinc deficiencies are practically unheard of in industrialized countries, a slight zinc deficiency is probably quite common.^{9 10}

Zinc intake in vegetarians and vegans

Studies show that the zinc intake of people on a vegetarian or vegan diet is often slightly lower than that of meat-eaters.^{11 12} While most vegetarians are nevertheless still within the recommended daily intake, people following a vegan diet often have lower zinc intakes than mixed eaters¹³ and adolescents following a vegetarian or vegan diet are slightly more likely to have low blood levels of zinc than their peers who consume animal-based products. The zinc intake of schoolchildren and older adolescents, especially girls, is generally unsatisfactory, regardless of diet. Suboptimal zinc intake has also been observed in older people who are following vegetarian or vegan diets. For all eating patterns, the likelihood of zinc deficiency increases with age.¹⁴

Despite their lower zinc intake compared to non-vegetarians, the zinc supply of adult vegetarians and vegans generally seems to be sufficient, with studies showing that zinc levels in the blood are similar for both groups.¹⁵ Nonetheless, it’s important to keep in mind the low availability of zinc in plant-based diets. Easy ways to increase the bioavailability and intake of zinc include germination, fermentation, soaking, and sprouting, as well as consuming fortified food and taking citric acid as a supplement. 

Conclusion

• Risk groups for low zinc levels include children, adolescents, pregnant women, breastfeeding mothers, and the elderly. All of these groups should ensure that they have a sufficient zinc intake by eating zinc-rich foods, regardless of whether they follow a vegetarian, vegan, or mixed diet.

• While people following a plant-based diet are likely to have lower levels of zinc, studies show that their overall zinc intake is nonetheless usually within the recommended range.
  
  

1. Kiouri, D. P., Tsoupra, E., Peana, M., Perlepes, S. P., Stefanidou, M. E., & Chasapis, C. T. (2023). Multifunctional role of zinc in human health: An update. EXCLI Journal, 22, 809-827. https://doi.org/10.17179/excli2023-6335
2. Bjørklund G, Dadar M, Pivina L, Doşa MD, Semenova Y, Aaseth J. The Role of Zinc and Copper in Insulin Resistance and Diabetes Mellitus. Curr Med Chem. 2020;27(39):6643-6657. doi: 10.2174/0929867326666190902122155. PMID: 31475889
3. Kiouri, D. P., Tsoupra, E., Peana, M., Perlepes, S. P., Stefanidou, M. E., & Chasapis, C. T. (2023). Multifunctional role of zinc in human health: An update. EXCLI Journal, 22, 809-827. https://doi.org/10.17179/excli2023-6335
4. Food Data Central.USDA. Available at: https://fdc.nal.usda.gov/
5. Maxfield L, Shukla S, Crane JS. Zinc Deficiency. [Updated 2023 Jun 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493231/
6. Maares, M., & Haase, H. (2020). A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models. Nutrients, 12(3). https://doi.org/10.3390/nu12030762
7. Scientific Opinion on Dietary Reference Values for zinc. EFSA,2015. Available at: https://www.efsa.europa.eu/en/efsajournal/pub/3844
8. Maxfield L, Shukla S, Crane JS. Zinc Deficiency. [Updated 2023 Jun 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493231/ 
9. Maares, M., & Haase, H. (2020). A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models. Nutrients, 12(3). https://doi.org/10.3390/nu12030762 
10. Maxfield L, Shukla S, Crane JS. Zinc Deficiency. [Updated 2023 Jun 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493231/ 
11. Davey GK, Spencer EA, Appleby PN, Allen NE et al. (2003): EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33883 meat-eaters and 31546 non meat-eaters in the UK. Public Health Nutr 6 (3), 259-69
12. Bakaloudi DR, Halloran A, Rippin HL, Oikonomidou AC, Dardavesis TI, Williams J, Wickramasinghe K, Breda J, Chourdakis M. Intake and adequacy of the vegan diet. A systematic review of the evidence. Clin Nutr. 2021 May;40(5):3503-3521. doi: 10.1016/j.clnu.2020.11.035. Epub 2020 Dec 7. PMID: 33341313
13. Klein, L., Dawczynski, C., Schwarz, M., Maares, M., Kipp, K., Haase, H., & Kipp, A. P. (2023). Selenium, Zinc, and Copper Status of Vegetarians and Vegans in Comparison to Omnivores in the Nutritional Evaluation (NuEva) Study. Nutrients, 15(16). https://doi.org/10.3390/nu15163538
14. Maares, M., & Haase, H. (2020). A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models. Nutrients, 12(3). https://doi.org/10.3390/nu12030762
15. Klein, L., Dawczynski, C., Schwarz, M., Maares, M., Kipp, K., Haase, H., & Kipp, A. P. (2023). Selenium, Zinc, and Copper Status of Vegetarians and Vegans in Comparison to Omnivores in the Nutritional Evaluation (NuEva) Study. Nutrients, 15(16). https://doi.org/10.3390/nu15163538