Zinc is vital for our health. It is the second most abundant trace element in the body and required for many of the chemical reactions in the body. Zinc plays an important role in fertility, the embryo’s development in the uterus and in gene expression. It is also essential for a healthy immune system, clear skin, for the body to maintain healthy glucose and lipid levels and for good thyroid function.
Foods Rich in Zinc
Oysters are an incredibly rich source of zinc, 6 medium sized oysters containing a whopping 76mg of zinc, more than five times the amount needed each day by a healthy adult.[1] [2]. Red meat, dried beans and legumes, nuts, seeds, eggs and dairy are also good sources. Some breakfast cereals are fortified with zinc.
However, phytates can limit the absorption of zinc from plant foods. It is found within the hulls and kernels of seeds, including those of nuts, grains, and legumes. Phytate binds with zinc and other minerals such as calcium and iron, preventing these minerals from being absorbed.
Reducing Phytates in Food to Maximise Mineral Absorption
Boiling, fermentation, germination and sprouting are all ways to remove phytates from food. For example, presoaking and then cooking whole red lentils for one hour have been shown to reduce phytate quantity by 80%.[3] Absorption of zinc can also be improved by using yeast-based breads and sourdough breads due to the leavening process.
Are Vegetarians & Vegans Likely to Be Deficient in Zinc?
It was originally thought that people who eat little or no animal products were likely to be low in zinc. However, vegetarians appear to adapt to lower zinc intakes by increased absorption and retention of zinc. Studies have shown [4] that vegetarians have similar serum zinc concentrations to, and no greater risk of zinc deficiency than, non-vegetarians (despite differences in zinc intake). Good sources of zinc for vegans include whole grains, tofu, tempeh, legumes, nuts and seeds and fortified breakfast cereals.
Who is most likely to be low in Zinc?[5]
- People with inflammatory bowel diseases such as coeliac and ulcerative colitis or who have had part of their gut taken out are likely to have low zinc levels.
- Women during pregnancy and breastfeeding need more zinc and are susceptible to zinc deficiency.
- Older infants who are exclusively breastfed may have low zinc levels. After 6 months old, the level of zinc in the mother’s breast milk reduces. Therefore, it is best to introduce nutrient rich foods around this time to complement breast feeding.
- 30% – 50% of heavy alcohol drinkers have low zinc levels.
- Certain medications can affect zinc levels e.g., thiazide diuretics can increase zinc excretion and some antibiotics can decrease its absorption.
Signs & Symptoms of Zinc Deficiency [1]:
People with zinc deficiency tend to have skin rashes, hair loss, recurrent infections and diarrhoea. Insufficient zinc is also associated with insomnia, dandruff, poor wound healing, acne and reduced appetite.
What is Zinc Used to Treat?[2]
Zinc can be given orally or applied to the skin. It is commonly used for known zinc deficiency and also for many conditions including skin and mucous membrane problems such as warts, acne, psoriasis, bed sores, nappy rash, cold sores and dandruff.
Other conditions it is also given for include:
Hormonal Issues
- Male infertility – Lack of zinc can cause low testosterone levels and sub-optimal sperm formation and motility.[3]
- Hypothyroidism [4]
- Diabetes – zinc is essential for insulin [5] to function properly and zinc levels tend to be low in diabetics. [6]
Infections
- Common cold- zinc lozenges can reduce the length and severity of the common cold.
- Mild gum disease & bad breath using a toothpaste containing zinc
- Pneumonia
Other Conditions
- Wilson’s disease- a rare inherited disorder that causes copper to accumulate in your liver, brain and other vital organs.
- Sickle cell disease- an inherited abnormality of red blood cells.
- Stomach ulcers.
- Depression -taken with antidepressants to increase their effectiveness.
- Attention Deficit & Hyperactivity Disorder
- Premature babies weighing less than 2500g to help them thrive.
- Age related macular degeneration.
- Decreased taste and smell.
Are Zinc Supplements Safe?
Zinc has the potential to be toxic if taken at too high a dose especially in the long term. While zinc is required for a healthy immune system, excessively high levels can actually lower immunity and also cause anemia due to copper deficiency. Zinc can also interact with medications and other supplements.
Therefore, It is advised to seek the advice of a health professional before taking zinc especially if you are on medication, have a chronic illness, are pregnant or breastfeeding – and before giving zinc supplements to children.
[1] Dunne, Lavon. J. Nutrition Alamanac 5th Edition ISBN 0-07-137338-1
[2] Nutrient Reference Values for Australia and New Zealand Including Recommended Dietary Intakes endorsed by the nhmrc on 9 September 2005 © Commonwealth of Australia 2006 ISBN Print 1864962372 ISBN Online 1864962437
[3] Petroski W, Minich DM. Is there such a thing as “anti-nutrients”? A narrative review of perceived problematic plant compounds. Nutrients. 2020 Sep 24;12(10):2929. doi: 10.3390/nu12102929
[4] Zinc and vegetarian diets Angela V Saunders, Winston J Craig and Surinder K Baines Med J Aust 2013; 199 (4): S17-S21. || doi: 10.5694/mja11.11493 Published online: 29 October 2013
[5] https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/
[6] Bland, Jeffrey S. et al Clinical Nutrition: A Functional approach
[7] Natural Medicine- Patient handout Zinc
[8] J Reprod Infertil.2018 Apr-Jun; 19(2): 69–81. PMCID: PMC6010824 PMID:30009140 Zinc is an Essential Element for Male Fertility: A Review of Zn Roles in Men’s Health, Germination, Sperm Quality, and Fertilization Ali Fallah, Azadeh Mohammad-Hasani, and Abasalt Hosseinzadeh Colagar
[9] Kravchenko, V.I., Andrusyshyna, I.M., Luzanchuk, I.A. et al. Association Between Thyroid Hormone Status and Trace Elements in Serum of Patients with Nodular Goiter. Biol Trace Elem Res 196, 393–399 (2020). https://doi.org/10.1007/s12011-019-01943-9
[10] Chabosseau, Pauline, and Guy A. Rutter. “Zinc and diabetes.” Archives of Biochemistry and Biophysics 611 (2016): 79-85.
[11] Salgueiro, M.J., Krebs, N., Zubillaga, M.B. et al. Zinc and diabetes mellitus. Biol Trace Elem Res 81, 215–228 (2001). https://doi.org/10.1385/BTER:81:3:215
