Research trials show a direct link to some cancer areas and selenium deficiency, an element often deficient in some soils and variations in many other soil types.
The article: The Importance of Selenium to Human Health (Lancet, Vol 356, Issue 9225) lists many overseas trials where adequate selenium has been shown to help asthma, eczema, viruses, sperm health, moodiness and depression. Little work has been done in New Zealand on rising serum selenium towards the 2umol/lt reached in the USA trial. A simple blood test will show up any deficiency and if deficient a simple supplement will help to reduce the impact of immune disorders and some cancers.
Exert from ‘Selenium Deficiency’ by David Walpole. HO mag Nov 2007.s