A Review of Dietary Selenium Intake and Selenium Status in Europe and the Middle East, 2015
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4377864/
3.1.1. Selenium Intake Studies: European Countries/UK

Eastern European countries tended to have lower Se intake than their western counterparts, as indicated by a Polish study [25], where Se content of the consumed foods was four-times lower than in Spain, which tended to have intakes that exceeded the DRI and RDA [26,27,28,29,30]. Studies in France [31] and Belgium [32] reported intakes equivalent to the RDA, while those from Slovenia [33] and Italy [34,35] found intakes below the RDA.

A 2008 longitudinal study in healthy British adults reported low Se intake [37]. Subsequently, the National Diet and Nutrition Survey (NDNS) 2008/2009 found that roughly 50% of adult women and older girls and 20% of men and older boys had Se intakes below the lower reference nutrient intake (LRNI) level [36]. A 2009 longitudinal analysis of Se intakes of Caucasian and South Asian women living in the UK who were enrolled in the vitamin D, Food Intake, Nutrition and Exposure to Sunlight in Southern England (D-FINES) study [60] showed that the RNI of Se was not achieved by 80%–90% of Caucasians and by 83%–95% of the South Asians. Likewise, 60% of the former and 60%–70% of the latter failed to meet the LRNI. The number of women that had Se intakes below the LRNI or RNI was not significantly different in terms of ethnicity. Only in the South Asian women was a seasonal variation noted, with significantly lower Se intake in the autumn [20].

3.1.2. Selenium Intake Studies: Middle Eastern Countries

Breast milk analysis in Turkey shows that Se content is below the international reference range set at 18.5 μg/L throughout the lactation period [61]. Analysis of various dairy products in Turkey also indicates that the Se content varies depending on the type of food. Butter and different types of cheeses had quite high concentrations, whereas other dairy products, such as milk and ice cream, contained negligible amounts.

The concentration of Se in water is extremely variable and, in some places, excessive, as reported in parts of Jordan [47]. However, a recent case-control study found Se intakes equivalent to the RDA in control subjects, while patients with colorectal cancers consumed significantly less [53].

Recent studies within Iran have reported adequate Se intakes within the general population [54,55], but extremely low intakes in oesophageal squamous cell carcinoma patients [57].

The concentration of Se in wheat grain grown in the KSA is extremely variable, with one study reporting a range from 8 to 293 μg/kg (median 78.4 μg/kg) [48]. The lowest Se content (average 50.6 μg/kg) was found in wheat from the Eastern parts of KSA, in the Wadi Al-Dowasir area, while the highest levels (average 285.5 μg/kg) was found in the northwest, around the Al-Jouf region. A further investigation of Se in soil, water and alfalfa from Al-Kharj in the centre of the country found that some samples had Se content as low as the low-Se zone in China [48].

Overall, Se intake varied throughout the Middle East. A recent study from Riyadh reported intakes nearly double the RDA [58], while a study from King Abdulaziz University in KSA reported intakes between 75 and 121.65 μg/person per day in a population sample in Jeddah [49]. In this study, the major food groups providing Se were cereals/cereal products, legumes and meats. Another study, including infant formulas, mostly imported from Europe, contained adequate levels of this trace element for infants up to six months [50,51]. However, some breast-fed children may still be at risk of low Se intakes, according to a study by Al Saleh et al., where intakes between 0.9 and 15 μg/day were reported [51,52].

3.2. Selenium Status Studies

The literature search located 48 European/UK studies and 44 investigations in the Middle East reporting Se status. A summary of the findings are presented in Table 3 and Table 4.

Table 3