What does zinc do?
What is zinc?
Found in our organs, tissues, bones, fluids and cells, zinc is one of the most important essential trace metals in human nutrition. It helps the body make new cells, process food and heal wounds, plus it boosts our resistance to infection. Food wise, it’s found mainly in shellfish and meat as well as in legumes, nuts and seeds. Some vegetarian and vegan foods, such as breakfast cereals, are fortified with it. Strict vegetarians, women who are breast-feeding and those with digestive problems like Crohn’s disease can be deficient.
How can I tell if I’m lacking?
Because zinc plays a role in so many functions, a lack can show up in various ways. Common signs include a diminished sense of smell and taste, a metallic taste in your mouth, poor wound healing, hair loss, rough skin, lethargy, and deformed nails. If you have any of these symptoms, see your GP to discuss your zinc intake.
Any research into the benefits of zinc?
When Finnish researchers analysed three randomised controlled trials they found that sucking zinc acetate lozenges could speed up recovery from the common cold threefold. On the fifth day of coughing and spluttering, 70% of those who had taken zinc had recovered compared with 27% of those who took a placebo. Meanwhile, other research, also from Finland, found that high-dose zinc lozenges shortened the duration of nasal discharge by 34%, nasal congestion by 37%, scratchy throat by 33%, and cough by 46%.
When US researchers gave people a supplement that combined antioxidants such as vitamin C and betacarotene along with zinc and copper, it slowed progression of the ‘wet’ form of the eye disease called age-related macular degeneration (AMD). Current drugs are expensive and can increase inflammation of the inside of the eye, but this daily supplement lowered the risk common type, accounting for around nine out of 10 cases, an estimated one in 10 people with dry AMD go on to develop wet AMD.
A US study found that just 4mg of extra zinc a day can make a major difference to the health of our cells, which in turn boosts the body’s ability to fight infection and disease. Zinc reduces ‘oxidative stress and damage to DNA’, which protects us against the onset of chronic cardiovascular diseases and some cancers. Without enough zinc, our bodies can’t repair wear and tear on our DNA, but scientists found that a mere 4mg was plenty. To put that in context, an egg contains around 1mg of zinc.
Recent American research shows zinc helps to control infection by preventing inflammation. A particular protein (NF-B) attracts zinc into key cells that respond quickly against infection. The zinc then helps fight the infection and also assists in balancing the immune response. If there isn’t enough zinc when you get an infection, it can lead to excessive inflammation, which may be why taking zinc tablets at the start of a cold can help to see it off more quickly.
How much do I need?
The recommended daily intake of zinc is 7mg for women and 9.5mg for men, which should be easy to get through a balanced diet. But because zinc isn’t found in large amounts in plant foods, vegans can lack it. The best plant-based sources are legumes, nuts, seeds, and oats as well as fortified cereals. Taking too much zinc can reduce the amount of copper the body can absorb, which can lead to anaemia and weakening of the bones, so don’t take more than 25mg of zinc supplements a day unless your doctor prescribes it.