Why you need zinc – and how to make sure you get enough

01 July 2020
by Glynis Horning

Zinc has raised its public profile since the Covid-19 pandemic, listed along with vitamins and other micronutrients as helping support the immune system, the better to fight off infection.

What is zinc?

Zinc is an essential trace mineral that assists your body in functions from synthesizing DNA to regulating immune responses, attacking viruses and bacteria, healing wounds and promoting healthy growth in childhood. 

What are the beneficial uses of zinc?

Courses of zinc have been found effective in treating childhood diarrhoea, it often features in creams to treat skin irritations (nappy rash, acne), and studies suggest it may help prevent age-related macular degeneration.  

A study in the journal Open Respiratory Medicine found taking zinc shortened colds by as much as 40%, and a Cochrane review reported zinc lozenges or syrup helped reduce the severity and length of colds when taken at the first signs. 

As yet there is no direct evidence that supplementation is effective in preventing or treating Covid-19, but it’s sensible to boost your immune system with a healthy diet that includes zinc. 

How much zinc do you need?

An adult man needs 11mg a day; an adult woman 8mg (11mg if you’re pregnant,12mg if breastfeeding). Children aged 1-3 years need 3mg; 4-8 years 5mg; 9-13 years 8mg; girls 14-18 years 9mg, and boys that age 11mg.

But, too much zinc may be harmful, and supplements should be used only with advice from a medical professional if you can’t get enough zinc from food sources. This may be the case if you have a strict vegetarian diet or a medical condition affecting absorption. 

The best food sources of zinc

The highest source is oysters, with six medium-sized ones providing 32mg. But other good sources are red meat, poultry and other seafood. Eggs and milk have smaller amounts, as do whole grains, beans and nuts, but in a form less available to the body, says Johannesburg dietitian Cheryl Meyer.

Supplements can’t replicate the complex variety of micronutrients and protective phytochemicals that work together in plant and other foods to provide what our bodies need to function optimally.

How to spot a zinc deficiency

Signs include anaemia, loss of appetite, slow healing of wounds, skin conditions such as eczema and acne, abnormal taste and smell, retarded growth, diarrhoea, hair loss and possibly depression.

Signs of taking too much zinc, on the other hand, include nausea, vomiting, headaches, stomach pains, diarrhoea and loss of appetite. Long term, excess zinc may have a role in developing kidney stones. 

Bottom line: "Aim to eat a healthy balanced diet to boost immunity", says Meyer, especially during the pandemic. 

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