A Scottish study demonstrated close links between selenium levels and male infertility.

96 men divided into eight groups in a double-blind placebo-controlled study were given either a composite tablet containing selenium and selected vitamins and minerals or a placebo. In those taking the selenium tablet sperm mobility increased by up to 80%, but fell back when they stopped taking the tablets.

The study found that a daily intake of 130mcg was needed to produce optimal improvement in sperm quality.

In the UK, the average daily intake of selenium is 31 micrograms (mcg) compared to a recommended daily dose of 60-70mcg.