Does zinc speed up recovery?
11/11/2024
Translation: Jessica Johnson-Ferguson
The body doesn’t need much of it. Just a few grammes of zinc is all you need to stay healthy. But what does it do? Is it true that the trace element wards off colds? Find out all you need to know about zinc here.
Zinc is vital, but can’t be produced by your body. Although it’s a trace element – meaning you only need very small quantities – the recommended 7 to 16 milligrammes a day are essential for your body to run smoothly. Not least because it can only store very small amounts. Only 2 to 3 grammes of zinc are in your body in total, the highest concentration being in the muscles (around 60 per cent). Incidentally, there’s a specific reason why the recommended daily intake (link in German) of the element has such a wide range, but more on that later.
Why your body needs zinc
Let’s take a closer look at why your body needs zinc. The trace element’s particularly important for a well-functioning immune response, wound healing and a large number of enzymes. DNA synthesis as well as cell division, development and growth can only run smoothly with the help of zinc. The trace element also plays an important role in taste and smell function, helps regulate hormones (including insulin, growth and sex hormones) and has antioxidant properties.
Can zinc shorten or even prevent a cold?
In addition to the well-known cold buster vitamin C, many cold remedies additionally contain zinc to boost your immune system. However, it hasn’t been proven that zinc can prevent a cold. Although there are pointers towards this – particularly in people with zinc deficiency – the evidence is unclear and results vary depending on the study. Some studies suggest that taking zinc regularly can reduce the likelihood of catching a cold, while others have found no such effect.
However, one meta-analysis did prove that zinc can shorten the duration of a cold by one day on average. For this to happen, it’s important to take the trace element within 24 hours after the first signs of a cold.
Foods containing a lot of zinc
As a general rule, zinc’s easier to absorb from animal products and is contained in meat, eggs, milk and dairy products. Plant-based sources of zinc include pulses, whole-grain products, nuts and seeds. Although the latter contain higher quantities of zinc per 100 grammes, there’s a catch: plants contain phytate. The problem with phytate is that it blocks the absorption of zinc.
What to do about phytate
Phytate is the major form of phosphate in plants and mainly found in seeds, grains, pulses and nuts. Food of animal origin generally doesn’t contain phytate. So the reason why zinc from animal sources can be better absorbed is that phytate binds zinc and other minerals. As a result, they’re no longer available for absorption in the intestine. If you consume lots of phytate at the same time as zinc, up to half of the zinc the respective food contains won’t be absorbed. If you follow a plant-based diet and eat a lot of pulses, you’ll be consuming large quantities of zinc, but also a lot of phytate. This means you’ll be excreting up to half of the zinc unused.
That’s the reason why the recommended daily intake of zinc varies from 7 to 16 milligrammes. Depending on how phytate-rich your diet is, the German Nutrition Society DGE (link in German) recommends different amounts of zinc. For men, this ranges from 11 mg per day for men with a low phytate intake to 14 mg per day for those with a medium phytate intake and up to 16 mg per day for those with a high phytate intake. For women, the recommended values are lower overall: 7, 8 or 10 mg depending on their phytate intake.
Does wholemeal bread lead to zinc deficiency?
You might be thinking that wholemeal bread and other wholemeal products can cause a zinc deficiency due to their high phytate content. But you can rest assured. If the phytate content hasn’t already been reduced by fermentation (for example in sourdough bread), wholemeal flour still contains enough zinc (1.5 mg per 100 g) to prevent a deficiency.
How to improve your zinc intake from plant-based foods
To improve zinc absorption, you should combine phytate-rich foods with zinc sources. Or try applying one of the following methods to reduce phytate content:
Soak: Soaking grains and pulses can break down the phytic acid they contain. The soaking water activates enzymes already present in the seeds (so-called phytases), which change the phytic acid in a way that makes it lose its ability to bind zinc and other minerals.
Germinate: Germinating seeds and grains triggers a very similar process to soaking. During germination, enzymes are activated that break down the storage substances in the seeds, thereby improving digestibility, among other things.
Ferment: Fermentation processes, such as those used in the production of sourdough bread, can also reduce the phytate content. The microorganisms that are active during fermentation produce enzymes that break down phytate.
The effects of zinc deficiency
As mentioned above, zinc is needed for many biological processes. This means a zinc deficiency can have far-reaching effects on the body. Common symptoms of zinc deficiency include a weakened immune function, which makes you prone to infections. Your skin can also be affected: slow wound healing, skin inflammation and rashes are typical signs. Hair loss and brittle nails may also be a sign. Zinc deficiency can also cause neurological issues such as mood swings, depression and difficulties concentrating. In children, a zinc deficiency can impair growth and development. It can also lead to a loss of appetite and changes in taste.
The effects of a zinc overdose
It’s relatively unlikely to have a zinc overdose from natural food sources, as the body is usually able to deal with excess zinc contained in food. However, the risk of an overdose increases if you’re taking [food supplements](/search?q=food supplements&is=food supplements).
In the short term, taking large quantities of zinc can have a toxic effect including nausea, vomiting and diarrhoea. In the long term, exceeding the recommended maximum amount of around 40 mg per day can lead to chronic health problems. A permanently high zinc level can impair copper absorption, which in turn can lead to a copper deficiency. This can impair the formation of red blood cells and the nervous system. In addition, immune function can be weakened and neurological symptoms such as headaches and dizziness can occur.
Find out more about vitamins, minerals and fibre and why they’re essential for your health here:
Header image: Monika Wisniewska/Shutterstock
Science editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always outside - somewhere in nature, preferably in my wild garden.