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

Abstract

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 mg kg À1 dry weight respectively and inter-quartile ranges varying from 0.015 mg kg À1 in 1982 to 0.019 mg kg À1 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 mg selenium, around one-tenth of the UK recommended intake values for men and women.

Symposium on ‘Geographical and geological influences on nutrition’ Factors controlling the distribution of selenium in the environment and their impact on health and nutrition

“…Knowledge of such factors can suggest health risks that might be relevant to a country or region by predicting which locations might be characterised by Se deficiency or toxicity. However, this direct relationship is 0·50 0·45 0·40 0·35 0·30 0·25 0·20 0·15 0·10 0·05 0·00 Wheat selenium (mg/kg dry weight) 1982 1992 1998 1982-4 1988 Adams et al (55) Wolnik et al…”

“…The Scientific Advisory Committee on Nutrition (34) reports that the main source of Se in the UK diet are breads, cereals, fish, poultry and meat and that rich dietary sources of Se include brazil nuts (Bertholletia excelsa), fish and offal; 3. reduced atmospheric deposition from fossil-fuel burning has reduced Se input into the surface environment. Coal can potentially be a very rich source of Se (15) ; 4. increased use of S fertilisers to overcome S deficiency in arable crops has meant that there is increased competition between S and Se in crop uptake (55) . S inputs from fertilisers and atmospheric deposition have an important influence on the Se status of wheat grain (56) .…”

Selenium Application Timing: Influence in Wheat Grain and Flour Selenium Accumulation Under Mediterranean Conditions

“…From these soil samples, total Se was determined as follows: a portion of each soil was finely ground (< 0.45 mm) using an agate ball mill (Retch PM 400 mill); 1 g was digested with ultrapure concentrated nitric acid (2 ml) and 30% w/v hydrogen peroxide (2 ml) using a closed-vessel microwave digestion protocol (Mars X, CEM Corp, Matthews, NC), and diluted to 25 ml with ultrapurified water (Adams, Lombi, Zhao, & McGrath, 2002). Sample vessels were thoroughly washed with acid before use.…”

Optimizing nutrient management for farm systems

“…The supply of selenium (Se) in the UK diet used to be adequate because UK bread was made with a large proportion of wheat from the USA that was rich in Se. Now that UK bread is baked with UK wheat, usually deficient in Se (Adams et al 2002), dietary intake of Se has declined and supplements are needed. Other issues of product quality in terms of trace element content and elemental balances are currently the subject of renewed interest.…”