Selenium: the antioxidant

You may not have heard of it, but selenium is a mineral you can’t do without - and mushrooms are one of the richest selenium sources you’ll find in the produce department. Just a handful (100g) provides around a third of adults’ daily selenium needs.

Selenium is one of eight trace minerals (or minerals with low concentration) that have been identified as essential to humans - sitting alongside other big names like iron and zinc. At the right levels, selenium protects our body against damage by acting as an antioxidant. It helps keep our immune system healthy, promotes healthy hair and nails, and even contributes to improved male fertility.

However, as with other trace minerals, more is not necessarily better. Too much selenium can be harmful to your body,* so you should take selenium supplements only when advised by your doctor. Eating mushrooms is a far safer, simpler way to get your daily dose.

What are antioxidants?

Antioxidants help neutralise the nasty free radicals that cause damage to our bodies, as well as boost our body’s own antioxidant defence mechanisms. Enzymes called glutathione peroxidases play a key role in the body’s detoxification system and protect against oxidative stress - and they need selenium to help them do their job.

Selenium & immunity

The immune system protects the body against infection, disease and viral infections. Selenium helps it work as it should by enabling enzymes known as selenoproteins to function properly.

What foods do we get selenium from?

While meat, eggs, dairy products and bread are the main sources of selenium in New Zealand diets, mushrooms are among the richest sources of selenium in the produce department. This makes them particularly important to vegetarians and vegans who aren’t able to get it through the other key sources. 

*Both low and high selenium levels appear to put young people at greater risk of depression, according to investigations by a psychology department team led by Dr Tamlin Conner. For more information visit: