Bioavailability

Studies have shown that bioavailability of organically bound forms of selenium is greater than inorganic forms.

• In a clinical trial, selenomethionine showed higher bioavailability (1.6 times) and much more effective in elevating plasma selenium and glutathione peroxide activity when compared to sodium selenite (Burk et al., 2006)
• Extended selenium status was witnessed in terms of increased activity of selenoenzymes as well as bioavailability with organic selenium forms than inorganic forms after supplementation has ended (Rayman, 2004)

Absorption

Generally about 80% of dietary selenium is absorbed by the body. However, factors like chemical species present in the diet, high dietary sulphur content (probably through competition owing to structural similarity) may retard selenium absorption (Sneddon, 2012; Briefing Paper, British Nutrition Foundation, 2001).