A guide to zinc and your immune system

Zinc is a key micronutrient that our body needs for a number of roles, from supporting growth and development to helping neurological functions.

It is also essential for our immune system, as it affects how our cells respond to infections, and can help keep inflammation under control.

As it is an element (Zn), our bodies cannot make zinc so it needs to come from our food – you can find it in beans, shellfish, whole grains and dairy.

If you are low in zinc, you may find cuts and scrapes take longer to heal, you may have diarrhoea, and you are more prone to getting ill.²

Why do we need zinc?

Zinc can help support:³

• DNA synthesis
• Carbohydrate metabolism
• Normal cognitive function
• Fertility and reproduction
• Bone health
• Eye health
• Immune function
• Healthy hair, skin and nails

Zinc is well-known for helping to cut the length of a common cold, but how else can it support our immune system?

How zinc helps your immune system

There are a number of ways zinc supports the immune system but primarily it activates enzymes that break down proteins in viruses and bacteria so they are less able to spread.⁴

Zinc also increases the activation of cells responsible for fighting infection.⁵

In 2011, French researchers discovered that zinc helps cells destroy microbes such as E. coli by overloading them.⁶ Essentially, this poisons them, killing them off.

Don’t worry though – the daily RDA for zinc is 7mg for women and 9.5mg for men.⁷ You’d have to consume at least 25mg a day for it to cause any problems.⁸

A 2017 US study carried out over six weeks found that taking just 4mg extra of zinc a day made a major difference to the health of cells, which in turn makes your body better able to fight infections and diseases.⁹

The team concluded that zinc reduces ‘oxidative stress and damage to DNA’ that helps protect against chronic diseases.

Zinc’s effect on inflammation

A growing area of research is looking at how zinc reduces inflammation in the body.

Inflammation has been linked to conditions such as heart disease, depression and dementia.

A 2013 study by Ohio State University found that zinc is ‘lured’ into cells that fight infection, to help stop the immune system spiralling out of control.¹⁰

The scientists concluded that if there wasn’t enough zinc to support this response, then excess inflammation is triggered – potentially damaging cells and the body.

A study by Jagiellonian University Medical College in Poland in 2017 discovered that zinc ‘exhibits antioxidant and anti-inflammatory activity’ which can potentially deter ill-health.¹¹

Zinc cuts the length of a cold

A meta-analysis of research published in Open Forum Infectious Diseases in 2017 found that zinc acetate lozenges can speed up recovery from colds.

On the fifth day of the cold, 70% of sufferers who took zinc had recovered compared with 27% of those who took a placebo.¹²

In 2015, an Australian trial also found that high-dose zinc lozenges (80mg a day) cut the duration of nasal discharge by 34%, nasal congestion by 37%, scratchy throat by 33%, and cough by 46%.¹³

Zinc is good for fertility

Zinc has long been associated with a positive impact on male fertility.

One study of 200 men published in the journal Fertility and Sterility in 2002 confirmed that normal sperm count increased after taking combined zinc sulfate and folic acid, in both fertile and sub-fertile men.¹⁴

How much zinc do you need?

The recommended daily amount of zinc is 7mg for women and 9.5mg for men.

There’s currently no reliable way of testing your zinc levels, but a deficiency is relatively rare in the West, where we tend to eat a varied and balanced diet.¹⁵

However, it has been found to be more common in old people – who may be eating less – while vegetarians and vegans can also be at risk, as one of the richest sources of zinc is meat and shellfish.

The good news is plenty of plant sources are also rich in zinc: lentils contain around 1.3mg per 100g, and firm tofu contains 2mg per 170g.¹⁶

How much zinc do children need?

• 1-3 years – 5mg a day
• 4-6 years – 6.5mg
• 7-10 years – 7mg
• 11-14 years – 9mg¹⁷

Zinc deficiency: What are the symptoms of a zinc deficiency?

Most people get enough zinc from their diet, but those at risk of deficiency include breastfeeding women, and vegetarians and vegans.

It’s thought that a naturally occurring type of plant compound called phytates – found in wholegrain cereals, beans and legumes – can bind to zinc and prevent it being absorbed properly by the body.

Symptoms of a zinc deficiency include:¹⁸

• loss of appetite
• poor immune function
• poor growth in children and pregnancy
• impotence
• wounds that won’t heal
• decreased sense of smell and taste

What happens if I consume too much zinc?

Excessive intakes of zinc can lead to nausea, vomiting, headaches, diarrhoea and stomach cramps.¹⁹

It can also inhibit the absorption of the minerals copper and iron.²⁰ This can lead to anaemia and weak bones.

The NHS recommends avoiding taking more than 25mg of zinc a day.²¹

Which foods are high in zinc?

Foods high in zinc include:

• shellfish
• cheese
• meat
• legumes including chickpeas
• nuts and seeds
• wholemeal bread
• fortified vegan foods

Good vegetarian sources of zinc are:

• chickpeas
• beans
• lentils
• nuts, including cashews, brazils and almonds
• seeds, particularly hemp, pumpkin and sesame
• milk
• cheese
• fortified breakfast cereals
• tofu

Your zinc-packed menu

Try the suggestions below to up your zinc intake.²² Remember that not all brands will contain the same levels of zinc.

Breakfast

Porridge made with 170g of oatmeal = 1mg of zinc

Mid-morning snack

28g of cashew nuts = 1.6mg

Lunch

Half a tin of baked beans = 2.9mg
Slice of wholegrain toast = 0.52mg

Mid-afternoon snack

Small pot of low-fat yoghurt = 0.8mg
1 tablespoon of flax seeds = 0.45mg

Dinner

Falafel burger made with 200g of chickpeas = 1.2mg
28g of whole milk mozzarella = 0.9mg
Large wholemeal pitta bread = 1mg

Total = 10.43mg of zinc

Avoid eating more than 25mg of zinc a day.

Zinc supplements: When should I take zinc supplements?

Eating a healthy, balanced diet should help you get all the zinc your body needs, but vegetarians, breastfeeding women and those with digestive disorders, like Crohn’s disease, who have trouble absorbing nutrients could consider a supplement.^23,24

 Should women take a zinc supplement in pregnancy?

No, you should be able to get all the zinc you need from a healthy, balanced diet.

What are the benefits of taking a zinc supplement?

Studies have found zinc supplements may:

• shorten the duration of the common cold²⁵
• support immune health²⁶
• support memory and concentration²⁷

Last updated: 17 September 2021