Whilst it is only required in small amounts within the body, selenium is a mineral that is vital to human health. It is found as components of proteins/enzymes which are present throughout many parts of the body and are known as ‘selenoproteins’. These selenoproteins serve many important functions within the body including:

- Protecting tissues from free radical damage.

- Required for thyroid hormone production.

- Selenium is needed for the proper functioning of the immune system.

Selenium Intake in the UK

Despite selenium being required for these functions a lot of people are unaware of its importance and some people haven’t even heard of it. It is recommended that women should consume 60ug and men 75ug per day. However in the UK only around 13% of adults are meeting this intake level. Not consuming enough selenium will mean that the functions of selenium listed above won’t be performed optimally.  

There is a large amount of variation in the selenium content of foods as it largely depends on the selenium content of the soil in which they are grown. In the UK we no longer source our wheat from America where the soil is selenium enriched. Instead we now get most of our wheat from Europe where there is less selenium present within the soil. This is one of the main reasons for the fall in intake levels over the past 30 years in the UK.

Sources of Selenium

• Brazil Nuts
• Meat
• Offal
• Seafood
• Fish

Toxicity

When selenium intakes are greater than the tolerable upper limit level of 400µg/day this can lead to toxicity and a condition known as Selenosis. Selenosis has many symptoms including the loss of hair and nails. The first indication that you are consuming too much selenium is a garlic odour on the breath.

Fortunately, based on the typical UK diet most people would struggle to get anywhere near this level. However be careful not to consume excessive amounts of Brazil nuts as they are very high in selenium and only 3-4 nuts will provide you with the daily recommended intake.

Selenium and Cancer

It has been suggested that selenium could potentially play a role in cancer prevention. Various studies have shown a higher selenium concentration within the body to be associated with a lower incidence of cancer.  It is selenium’s role as a component of selenoproteins with antioxidant properties which has been suggested as the mechanism responsible for this association. (World Cancer Research Fund (WCRF) 2007). However at the moment the evidence is inconclusive and therefore this association requires more research.