Zinc is crucial to maintaining good health and controlling blood glucose levels. This essential nutrient is vital in ensuring our β-cells and insulin function properly. It can even help to prevent diabetes and its related complications, including eye and kidney disease.

This article will discuss how zinc regulates blood glucose, its sources, recommended intake, and potential health risks associated with insufficient and excessive intake. Let’s dive in!

The Role of Zinc in Glucose Regulation

Zinc regulates blood glucose by maintaining the proper function of β-cells and insulin (Poudel et al., 2017).

β-cells are specialised cells in the pancreas that produce and release insulin, a hormone that moves glucose from the blood into the cells for energy or storage in the liver and muscles (Rahman et al., 2021). Insulin also helps prevent the liver from releasing glucose into the bloodstream when unnecessary (Rahman et al., 2021).

Research has shown that zinc is necessary to make, store and release insulin (Chabosseau and Rutter, 2016). Zinc is involved in the processing and utilisation of glucose in various cells, including the liver, muscle, and fat. It also plays a role in the signalling pathways that regulate insulin release from β-cells.

Studies show that zinc benefits glucose metabolism in people with diabetes. For example, a 2019 study showed that zinc supplements improved glucose control and reduced the risk of complications in people with Type 2 diabetes (Wang et al., 2019).

Other studies show zinc supplements can improve metabolic health in women with gestational diabetes (Karamali et al., 2015).

How much zinc do you need daily?

According to 2016 Public Health England guidelines, men need around 9.5 mg of zinc daily, while women need around 7 mg daily. Pregnant and breastfeeding women may need more.

Insufficient zinc intake can occur if the body doesn’t absorb zinc properly from food. It can also occur from poor intake of zinc-rich foods and excessive losses during illnesses, such as diarrhoea (Roohani et al., 2013).

Insufficient intake can lead to health problems such as poor growth, reproductive problems, impaired taste and smell, recurrent infections, poor hair growth and skin problems (Maxfield et al., 2023; Plum et al., 2010).

It is worth noting that excessive zinc intake can also cause health problems; this is discussed below.

Top Food Sources of Zinc

Zinc is found in various foods, including meat, seafood, dairy products, whole grains, nuts, and seeds. Good sources of zinc include:

• Oysters – 74 mg per 6 medium oysters
• Beef – 7 mg per 3 oz serving
• Pork – 2.9 mg per 3 oz serving
• Chicken – 1.3 mg per 3 oz serving
• Crab – 6.5 mg per 3 oz serving
• Lobster – 3.4 mg per 3 oz serving
• Beans (baked beans, chickpeas, kidney beans) – 2 mg per 1 cup serving
• Nuts (cashews, almonds, peanuts) – 1-1.5 mg per 1 oz serving
• Whole grains (wheat germ, quinoa, oats) – 1-2 mg per 1 cup serving
• Dairy products (milk, cheese, yoghurt) – 1 mg per 1 cup serving

Please note that the zinc content in foods can vary depending on factors such as soil quality, processing, and cooking methods. Therefore, it is best to aim for a variety of zinc-rich foods to meet your daily zinc needs.

How vegans can get enough zinc

Zinc is found in many plant-based foods, but those sources typically contain compounds that can inhibit zinc absorption. Phytates are one of such compounds. They are found in legumes, whole grains, and nuts and can bind to zinc and reduce its absorption in the gut (Pires et al., 2023).

Oxalates are another compound in spinach, beet greens, and rhubarb that can inhibit zinc absorption. Vegans may also have difficulty getting enough zinc due to their diet (Lopez-Moreno et al.., 2022).

Fortunately, there are ways that vegans can enhance their zinc absorption from plant-based sources. For example, soaking, sprouting, and fermenting beans, grains, and seeds can help reduce the phytate content and increase zinc bioavailability (Samitya et al., 2020; Lopez-Moreno et al., 2022).

Eating zinc-rich foods with vitamin C-rich foods, such as citrus fruits, can also enhance zinc absorption (Lopez-Moreno et al., 2022).

In addition, vegans need to be mindful of their overall diet and ensure they get enough zinc from various sources. Some good vegan sources of zinc include legumes, tofu, tempeh, nuts, seeds, and whole grains.

A registered nutritionist can help vegans plan a balanced diet that meets their nutritional needs, including their zinc intake.

Consequences of Excessive Zinc Intake

While zinc is essential for good health, excessive zinc intake can adversely affect the body. Here are some potential consequences of excess zinc intake (Agnew & Slesinger, 2022; Ceballos-Rasgado et al., 2022; Plum et al., 2010):

• Digestive issues: High doses of zinc can cause nausea, vomiting, and diarrhoea. It can also interfere with absorbing other essential minerals such as copper and iron.
• Headaches and dizziness: Excessive zinc intake can cause headaches and dizziness.
• Reduced immune function: Zinc is essential for immune function, but too much zinc can weaken the immune system and make it difficult for the body to fight infections.
• Copper deficiency: Excess zinc can interfere with the absorption of copper, leading to copper deficiency. Copper is necessary for producing red blood cells, maintaining healthy bones and joints, and proper brain function.
• Lowered levels of HDL cholesterol: High doses of zinc can reduce HDL cholesterol levels, which is considered “good” cholesterol, as it helps remove excess cholesterol from the bloodstream.
• Kidney and liver damage: Prolonged excess zinc intake can lead to kidney and liver damage.

Note that the adverse effects of excess zinc intake are usually associated with high doses of zinc from supplements rather than from dietary sources. Therefore, getting adequate zinc from a balanced diet is the best way to maintain good health.

In conclusion,

Zinc is a vital nutrient that plays a significant role in regulating blood glucose levels and maintaining good health. While zinc is essential for good health, excessive intake can lead to various health risks.

Therefore, it is essential to maintain a balanced diet and consult a healthcare professional before taking any zinc supplements.

If you are concerned about your zinc intake, consider speaking to a registered dietitian or nutritionist who can help you plan a balanced diet that meets your nutritional needs.

References

• Poudel, R.R., Bhusal, Y., Tharu, B., & Kafle, N.K. (2017) Role of zinc in insulin regulation and diabetes. Journal of Social Health and Diabetes, https://doi.org/10.4103/joshd.J_Soc_Health_Diabetes_13_17.
• Rahman, M.S., Hossain, K.S., Das, S., Kundu, S., Adegoke, E.O., Rahman, M.A., Hannan, A., Uddin, J., Pang, M-G. (2021) Role of insulin in health and disease: an update. International Journal of Molecular Sciences, 22(12): 6403. Https://doi.org/10.3390/ijms22126403
• Chabosseau, P., & Rutter, G.A. (2016) Zinc and diabetes. Archives of Biochemistry and Biophysics, 611: 79-85. Https://doi.org/10.1016/j.abb.2016.05.022.
• Wang, X., Wu, W., Zheng, W., Fang, X., Chen, L., Rink, L., Min, J., & Wang, F. (2019) Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomised controlled trials. American Journal of Clinical Nutrition, 110(1): 76-90. Https://doi.org/10.1093/ajcn/nqz041.
• Karamali, M., Heidarzadeh, Z., Seifati, S.M., Samimi, M., Tabassi, Z., Hajijafari, M., Asemi, Z., & Esmaiillzadeh, A. (2015) Zinc supplementation and the effects on metabolic status in gestational diabetes: a randomised double-blind, placebo-controlled trial. Journal of Diabetes Complications, 29(8): 1314-9. Https://doi.org/10.1016/j.diacomp.2015.07.001.
• Public Health England (2016) Government Dietary Recommendations. Goverment recommendations for energy and nutrients for males and females aged 1-18 years and 19+ years. Available: https://assets.publishing.service.gov.uk/media/5a749fece5274a44083b82d8/government_dietary_recommendations.pdf. Last accessed: 10 January 2024
• Roohani, N., Hurrell, R., Kelishadi, R., & Schulin, R. (2013). Zinc and its importance for human health: An integrative review. Journal of Research in Medical Sciences: The Official Journal of Isfahan University of Medical Sciences, 18(2), 144-157. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724376/
• Maxfield, L., Shukla, S., Crane, J.S. (2023) Zinc Deficiency. Available: https://ncbi.nlm.nih.gov/books/NBK493231. Last accessed: 10 January 2024.
• Plum, L. M., Rink, L., & Haase, H. (2010). The Essential Toxin: Impact of Zinc on Human Health. International Journal of Environmental Research and Public Health, 7(4), 1342-1365. https://doi.org/10.3390/ijerph7041342
• Pires, S. M., Reis, R. S., Cardoso, S. M., Pezzani, R., Seilkhan, A., Ydyrys, A., Martorell, M., Sönmez Gürer, E., Setzer, W. N., Abdull Razis, A. F., Modu, B., & Calina, D. (2023). Phytates as a natural source for health promotion: A critical evaluation of clinical trials. Frontiers in Chemistry, 11, 1174109. https://doi.org/10.3389/fchem.2023.1174109
• Samitya, M., Aluko, R.E., & Dhewa, T. (2020) Plant food anti-nutritional factors and their reduction strategies: an overview. Food Production, Processing and Nutrition, https://doi.org/10.1186/s43014-020-0020-5.
• López-Moreno, M., Garcés-Rimón, M., & Miguel, M. (2022). Antinutrients: Lectins, goitrogens, phytates and oxalates, friends or foe? Journal of Functional Foods, 89, 104938. https://doi.org/10.1016/j.jff.2022.104938
• Agnew, U.M & Slesinger, T.L (2022) Zinc toxicity. Available: https://www.ncbi.nlm.nih.gov/books/NBK554548. Last accessed: 10 January 2024.
• Ceballos-Rasgado, M., Lowe, N.M., Mallard, S., et al. (2022) Adverse effects of excessive zinc intake in infants and children aged 0-3 years: a systematic review and meta-analysis. Advances in Nutrition, 13(6): 2488-2519. Https://doi.org/10.1093/advances/nmac088.

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