Brazil nuts are a rich source of selenium but until now no studies have investigated how available this mineral is for us to use (bioavailability). Researchers from the University of Otago in Dunedin in New Zealand found that consuming just two Brazil nuts a day for 12 weeks increased the amount of selenium in the blood by over 60 per cent. The authors of this study concluded that including Brazil nuts in the diet could avoid the need for supplements.
Thomson CD, Chisholm A, McLachlan SK, Campbell JM. 2008. Brazil nuts: an effective way to improve selenium status. American Journal of Clinical Nutrition. 87 (2) 379-384.