Original article Determination of selenium content in selected Pakistani foods Shahid Iqbal, 1 * Tasneem Gul Kazi, 2 Muhammad Iqbal Bhanger, 2 Mubeena Akhtar 2 & Raja Adil Sarfraz 2 1 Department of Chemistry, University of Sargodha, Sargodha, 40100-Pakistan 2 National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro-76080-Pakistan (Received 04 October 2005; Accepted in revised form 27 June 2006) Summary Owing to increased concern in a number of diseases associated with low-selenium (Se) foods, the estimation of total Se content (TSC) is the focus of research these days. TSC was determined in fruits, vegetables, meat, milk, poultry, fish and cereals. Hydride generation atomic absorption spectrometric method was employed using the wet digestion method. Different certified reference materials were used for the validation of the method. The lowest Se content was found in plant-based foods, whereas the highest was in fish and appreciable in other animal-based foods. The data was compared with TSC data from other countries. TSC in Pakistani foods was comparable with other countries, with few exceptions. This report may serve as a database for TSC in Pakistani foods. Keywords Foods, hydride generation atomic absorption spectrometry, selenium content. Introduction Selenium (Se) is an essential trace element required in small amounts by animals and humans for the basic functions of life and nutrition. Se has been reported as a potent antioxidant with selenoenzyme, glutathione per- oxidase, which controls the oxidation process at cellular levels (Cohen & Avissar, 1994; Sunde, 1994) by reducing lipid hydroperoxide content and protecting biological membranes from oxidative degradation (Rayman, 2000). Selenoproteins and other Se metabolites have become popular owing to their vital role in immune function, maintenance of fertility and possibly some anticancer effects (Rayman, 2000). Research on seleno- proteins is still in progress, and about thirty-five selenoproteins have been identified till date (Rayman, 2000). Their functionality is dependent on bioavailable Se content in diet. Higher content of Se is toxic and exerts adverse effects on health, while deficiency of Se has been found to be associated with a number of diseases, including Keshan (Yang et al., 1984), cancer (Clark et al., 1996), cardio- vascular diseases (Kardinaal et al., 1997), viral diseases (Beck & Levander, 1998; Taylor et al., 1997), inflam- matory conditions, diabetes mellitus, hepatopathies, HIV infection (Holben & Smith, 1999), etc. Many European Union countries have suffered from signifi- cant reduction of Se content in foods in the last 20 years, resulting in the aforementioned diseases (Alfthan & Neve, 1996). Based on these reports, many countries have recommended measures to improve Se content of foods by adding Se fertilizers to agricultural crops, and by growing and importing Se-rich foods (Robinson, 1989). Se is present in appreciable amounts in different foods like cruciferous vegetables, legumes, cereals, nuts, fruits, milk (Arruda et al., 1996; McNaughton & Marks, 2002). The recommended dietary allowance (RDA) [IOM, 2000] for Se is 55 lg per day for adult. The minimum Se concentration, which may be considered enough to combat diseases is 30–70 lg per day for adult, as recommended by German, Austrian and Swiss Nutri- tion Associations (Reference Values for Nutrient Intake, 2002), while maximum intake level for adults is set at 400 lg per day (IOM, 2000). As the range between essential and toxic levels of Se in human nutrition is narrow (Rayman, 2000), it suggests the importance of accurate determination of TSC in food samples (Maha- patra et al., 2001). Most EU countries have Se dietary levels below RDA guidelines. The concentration of Se in different foods and the amount of foods consumed daily per capita is required to calculate the daily dietary intake, before recommending daily dietary allowance, because Se varies over a wide range in different foods depending on the geographical origin (Pendias, 2001). This is mainly attributed to variations in total Se content in soil, and also because of its variable availability to plants that are controlled by soil composition and pH (Fordyce et al., 2000). Selenium is richly present in high protein foods i.e. eggs, meats (Klapec et al., 1998). Entrails and seafood contain 0.4–1.5 mg kg )1 , muscle *Correspondent: Fax: +92 48 3222121; e-mail: ranashahid313@gmail.com International Journal of Food Science and Technology 2008, 43, 339–345 339 doi:10.1111/j.1365-2621.2006.01447.x Ó 2007 The Authors. Journal compilation Ó 2007 Institute of Food Science and Technology Trust Fund