Selenium is a mineral that works as an antioxidant together with vitamin E. It also helps keep the male sperm and prostate gland healthy.

Selenium operates as co-factor to your antioxidant enzyme systems, protecting your cells from damage by neutralising free radicals, which have been linked to heart disease and some cancers. It also bonds with metals such as mercury and arsenic, preventing them from causing illness. Selenium keeps sperm and the prostate gland healthy in men.

No RDA has been established yet, but one guideline – set by the UK government – is for 75mcg daily, the equivalent of about five Brazil nuts. The range for supplemental intake is 50–200mcg a day. When selenium is bonded in an amino acid chelate as selenomethionine, it’s regarded as one of the best forms of supplement available.

Nuts, especially Brazil nuts, cashews and walnuts, fish such as tuna and sole, grains such as rice and wheat.

Low selenium levels appear to allow otherwise benign viruses to become active, leading to infections. Other signs of deficiency are dandruff, poor male fertility and prostate health, premature ageing and weak muscles.

More than 200mcg isn’t recommended. More than 3.2mg can lead to hair loss and halitosis.

A daily supplement of 200mcg of selenium and 160mg (200 IU’s) of vitamin E reduces the symptoms of acne. People with diets that are rich in selenium have lower rates of cancer than others. Selenium also helps reduce damage to the heart’s artery walls and reduces the fatty build-ups that can clog them.