Zinc – Overview, Health Benefits & Side Effects

Zinc
Medically approved by
Dr Earim Chaudry
Last updated
30th July 2020

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Zinc is a trace mineral that can be found in every cell of your body. It’s necessary for enzyme activity, healing and immunity, and brain function. Keeping your zinc levels topped up is important for your fertility, your hair and skin, and even your mental health.
Food sources of zinc include shellfish, meat, dairy products, beans, and lentils. You can also take a zinc supplement to increase your zinc intake and prevent deficiency. Low doses of zinc are unlikely to cause side effects, but taking a high dose over a long period of time isn’t generally recommended.

After iron, zinc is the most common trace mineral in your body and it’s essential for many of your body’s processes to function normally. As you can’t store zinc in your body, you need to make sure that you’re topping up your zinc levels regularly through your diet and/or a supplement.

In this article, we explore: why zinc is important is important for your body and maintaining good health, the signs and causes of zinc deficiency, what foods or supplements are good sources of zinc, and the possible side effects of taking too much zinc.

Why Is Zinc Important for Your Body?

Zinc is present in every single cell of your body, playing a key role in cell division and cell growth. It also helps to stimulate the activity of hundreds of different enzymes, which are then involved in your digestion, metabolism of energy, nerve function, and much more. 

When you were growing up zinc was crucial for your body to develop and mature properly. As an adult, zinc continues to affect your mental development as it is involved in memory formation and learning.

Zinc is also essential for your body to defend and heal itself. It helps you build up a healthy immune system that can fight off disease and infection, and it contributes to blood clotting and wound healing when you are injured.

What Are the Health Benefits of Zinc?

Scientific evidence suggests that zinc has the ability to help treat a variety of medical conditions and health concerns. These include:

Fertility: Low zinc levels have been linked to poor sperm quality and sperm count. It’s thought that getting enough zinc is necessary for healthy testosterone production in your body, which then allows your body to make healthy sperm.

Skin Conditions: Skin conditions such as acne and psoriasis can be treated with zinc, either as a topical ointment or a supplement, and have shown significant improvement in clinical trials.

Immunity: Taking zinc supplements has been demonstrated to strengthen the body’s immunity to the common cold and shorten the duration of cold symptoms.

Eyesight: Clinical trials have suggested that zinc treatment may help reduce the risk of age-related macular degeneration.

Depression: For patients suffering from depression that is resistant to treatment, it’s been demonstrated that taking zinc supplements alongside antidepressant medication is more successful at tackling depression than the medication alone.

Hair: A study on men with male pattern baldness and other types of hair loss found that the participants had lower zinc levels than the control group, so getting enough zinc in your diet may help to prevent hair loss.

What Are the Symptoms of Zinc Deficiency?

Zinc deficiency can occur when you’re not getting enough zinc in your diet or if your body is not absorbing it properly. It can also be the result of health conditions such as liver or kidney disease, Crohn’s disease, coeliac disease, diabetes, or alcoholism.

The symptoms of zinc deficiency include:

  • Loss of appetite
  • Abnormal sense of taste and smell
  • Diarrhoea
  • Anaemia
  • Slow wound healing
  • Skin conditions such as acne and eczema
  • Depression
  • Hair loss
  • Low testosterone levels (hypogonadism)

Which Foods to Eat for Zinc?

The best dietary sources of zinc are animal products, as the body finds it easier to digest zinc from these foods. Rich sources of zinc are:

  • Shellfish – oysters, crab, lobster
  • Meat – beef and pork
  • Dairy products and eggs

Zinc is also found in plant foods such as:

  • Beans, peas, and legumes
  • Nuts and seeds
  • Whole grains – brown rice, wholemeal bread

If you’re a vegetarian or vegan you need to be extra careful about your zinc intake. This isn’t simply because the body struggles to absorb zinc from plant sources; it’s also because key sources of plant protein, like legumes, often contain phytates, a chemical that further obstructs the body’s ability to absorb zinc.

Should I Take a Zinc Supplement?

The RNI (Reference Nutrient Intake) of zinc for men over 18 is 9.5mg per day. However, you can generally have up to 40mg of zinc per day (including food sources and supplements) without experiencing adverse effects.

You might want to take a zinc supplement if you are a vegetarian or vegan (see above), if you are an athlete (as zinc is lost through sweat), or if you have a health condition that affects your zinc levels. Or you may just want to give your immunity a boost.

A supplement with a low dosage of zinc (5–10mg) is suitable for preventing zinc deficiency in otherwise healthy men. However, to treat zinc deficiency you’ll probably need a supplement with a dose of 25–45mg per day. Taking extra-high zinc supplements isn’t a good plan in the long-term, as that can cause adverse side effects (see below).

When choosing a zinc supplement, look for a product that contains zinc citrate or zinc gluconate as these are more easily absorbed by the body. 

Are There Any Side Effects of Taking Zinc Supplements?

You’re unlikely to experience any side effects from a low to medium daily dose of zinc. However, taking supplements containing over 100mg of zinc on a regular basis can cause gastrointestinal symptoms. One study found that taking 150mg zinc every day for 6 weeks resulted in abdominal cramps, vomiting, and nausea.

When you take too much zinc this can also affect your body’s ability to absorb copper, another important trace mineral. Symptoms of copper deficiency include anaemia, low white blood cell count, and neurological issues. So it’s better to steer clear of high-dose zinc supplements unless you’re advised to take them by your doctor.

Key Takeaways…

Whether you want to boost your testosterone levels, your hair growth, or your immunity, keeping up your zinc intake is important. Aim to include lots of zinc-rich foods in your diet and consider a supplement if you feel you need extra nutritional support.

References

  1. Abasalt Hosseinzadeh ColagarEisa Tahmasbpour MarzonyMohammad Javad Chaichi (2009). Zinc levels in seminal plasma are associated with sperm quality in fertile and infertile men: https://www.ncbi.nlm.nih.gov/pubmed/19285597

     

  2. Mrinal Gupta, Vikram K. Mahajan, Karaninder S. Mehta, and Pushpinder S.Chauhan (2014). Zinc Therapy in Dermatology: A Review: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4120804/

  3. Harri Hemilä (2011). Zinc Lozenges May Shorten the Duration of Colds: A Systematic Review: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136969/

  4. Rohini VishwanathanMei ChungElizabeth J. Johnson (2013). A Systematic Review on Zinc for the Prevention and Treatment of Age-Related Macular Degeneration: https://iovs.arvojournals.org/article.aspx?articleid=2189216

  5. Elham Ranjbar, MS, Masoumeh Sabet Kasaei, PhD, Minoo Mohammad-Shirazi, MD, PhD, Javad Nasrollahzadeh, PhD, Bahram Rashidkhani, PhD, Jamal Shams, MD, Seyed-Ali Mostafavi, MSc, and Mohammad Reza Mohammadi, MD (2013). Effects of Zinc Supplementation in Patients with Major Depression: A Randomized Clinical Trial: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3796297/

  6. Emily L. Guo and Rajani Katta (2017). Diet and hair loss: effects of nutrient deficiency and supplement use: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315033/

  7. British Nutrition Foundation – Nutrition Requirements: https://www.nutrition.org.uk/attachments/article/234/Nutrition%20Requirements_Revised%20Oct%202016.pdf

  8. Laura M. Plum, Lothar Rink, and Hajo Haase (2010). The Essential Toxin: Impact of Zinc on Human Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872358/

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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