Selenium and Health: An Update on the Situation in the Middle East and North Africa

Abstract

Selenium (Se) is an important trace element that should be present in the diet of all age groups to provide an adequate intake. Se is incorporated in 25 known selenoproteins, which mediate the biological effects of Se including, immune response regulation, maintenance of thyroid function, antioxidant defense, and anti-inflammatory actions. A balanced intake of Se is critical to achieve health benefits because depending on its status, Se has been found to play physiological roles or contribute to the pathophysiology of various diseases including, neurodegenerative diseases, diabetes, cancer, and cardiovascular disorders. Se status and intake are very important to be known for a specific population as the levels of Se are highly variable among different populations and regions. In the Middle East and North African (MENA) region, very little is known about the status of Se. Studies available show that Se status is widely variable with some countries being deficient, some over sufficient, and some sufficient. This variability was apparent even within the same country between regions. In this review, we summarized the key roles of Se in health and disease and discussed the available data on Se status and intake among countries of the MENA region.

First Trimester Microelements and Their Relationships with Pregnancy Outcomes and Complications

“…In developed countries, there is currently no deficiency of zinc, which may be the result of various national dietary interventions [72]. Low levels of selenium are found in some regions of the world [70,71]. In our country, the average Se concentration is 70 µg/L (50−55 µg/L in some regions), and in North America it is 122.4−151.8 µg/L [70,73,74].…”

“…Geographical differences in the content of elements in soil mainly concern selenium and affect the differences in the content of this element in plants and animals, and then in people [70,71]. In developed countries, there is currently no deficiency of zinc, which may be the result of various national dietary interventions [72].…”

“…In our country, the average Se concentration is 70 µg/L (50−55 µg/L in some regions), and in North America it is 122.4−151.8 µg/L [70,73,74]. Recommendations for the optimal amount of Se in the diet are based on maximizing glutathione peroxidase (GPx) [70,71]. The optimal mean serum concentration of Se (according to the World Health Organization) is 39.5-194.5 µg/L for healthy adults, and 70−90 µg/L was considered to maximize GPx.…”

Loss of Selenov predisposes mice to extra fat accumulation and attenuated energy expenditure

“…Elevated lipogenesis, coupled with decreased lipolysis and energy expenditure, often leads to positive energy balance, excessive fat accumulation, and eventually obesity [ [1] , [2] , [3] ]. Selenium (Se) and Se-dependent proteins have shown important roles in body lipid and energy metabolism [ [4] , [5] , [6] , [7] ], despite their well-known primary functions in redox control and antioxidant defense [ 8 , 9 ]. Knockout (KO) or overexpression of selenoprotein genes such as Gpx1 [ 10 , 11 ], Selenop [ 12 ], Selenom [ 13 ], Dio2 [ 14 ], and Selenot [ 15 ] in mice induced insulin resistance and obesity.…”

Endoplasmic reticulum stress and oxidative stress drive endothelial dysfunction induced by high selenium

“…In fact, much evidence from in vivo and in vitro reports indicates that excessively low and high selenium concentrations are associated with a higher risk of disease, including diabetes and cardiovascular disease (Bleys et al, 2007; Bleys, Navas‐Acien, & Guallar, 2008; Bleys, Navas‐Acien, Stranges, et al, 2008; Labunskyy et al, 2011; Rayman, 2012; Rocourt & Cheng, 2013). This U‐shaped relationship between selenium status and optimal health suggests a complex role for selenium in physiology (Bleys, Navas‐Acien, Stranges, et al, 2008; Ibrahim et al, 2019; Rayman, 2020). Although a few observational studies found an inverse association between selenium status and cardiovascular risk, post hoc analysis of the Nutritional Prevention of Cancer trial found that long‐term supplementation with selenium (200 µg/day) increased type‐2 diabetes risk (Stranges et al, 2007) a condition intimately associated with endothelial cell dysfunction and cardiovascular complications (Maamoun, Benameur, et al, 2019).…”