Evidence of low selenium concentrations in UK bread-making wheat grain

The selenium concentration of representative bread-making wheat (Triticum aestivum L) samples was measured in national grain surveys collected in 1982 (n (number of samples) = 180), 1992 (n = 187) and 1998 (n = 85) from major wheat-growing regions around the UK. The means and distributions of selenium concentrations over the three years were similar, with mean grain concentrations of 0.025, 0.033 and 0.025 mgkg(-1) dry weight respectively and inter-quartile ranges varying from 0.015 mgkg(-1) in 1982 to 0.019 mgkg(-1) in 1992 samples. No long-term changes in the distribution of wheat selenium concentrations were found over the 17 year period. Geographical mapping of the concentrations identified an area of eastern England as having high grain concentrations compared with other UK regions. There were no significant correlations between grain selenium and grain sulphur concentrations for the national survey samples. However, at an individual field experimental site, increasing the rate of sulphur addition was found to decrease grain selenium concentration significantly. The daily UK dietary contribution of selenium from wheat-based products was estimated and the daily intake was calculated to be 6.4 mug selenium, around one-tenth of the UK recommended intake values for men and women. (C) 2002 Society of Chemical Industry.