Selenium isn’t a supplement that we hear a lot about, especially in the sports nutrition world, but it’s slowly making its way up the ranks as one of the top choices for supporting overall health. Despite only being required in small amounts, this trace mineral plays some big roles.But one of the questions we’re hearing around town—and everyone in the fitness world wants to know—can selenium help with weight loss?It may not be the magic pill to help you shed pounds like that, but we’re breaking down what you need to know about the link between selenium and weight management.
What Is Selenium?
Before we dive into why selenium supplementation—either through diet or pills—is important, let’s first take a look at what selenium actually is, because if we’re being honest, most people aren’t even aware that it’s essential for optimal body function.Selenium is a trace mineral, meaning it’s required in very small amounts, that plays a big role in the body due to its incorporation into selenoproteins—a group of 25 proteins that have a major role in oxidoreduction reactions, but also have biochemical activities and/or physiological roles in immune function, reproduction, cognitive function, and thyroid health 1.
Selenium also plays structural and enzymatic roles, both as a catalyst and an antioxidant 2. And although selenium is widely available in several food sources, things like soil quality, rainfall, evaporation, and pH levels all influence the concentration of selenium in foods.
Health Benefits Of Selenium
So, if selenium is required in such small amounts, why is getting enough of it important?
Immune function
The immune system is a complex interplay between several other organ systems in the body, but it requires some specific nutrients to function optimally, one being selenium. Because of its role in selenoprotein, selenium is found in several immune tissues such as the liver, spleen, and lymph nodes 3.
Selenium deficiency has been associated with functional impairment of several types of immune cells, including B cells, T cells, lymphocytes, and natural killer (NK) cells that are required for proper immune responses.
Reproduction
Regardless of whether kids are in your cards, a healthy reproductive system is important for optimal health. For men, selenium plays an important role in supporting sperm function, growth, development, and motility, but it’s also required for the synthesis of testosterone, which plays a key role in athletic performance and recovery 3, 4.
Insufficient levels of testosterone have been linked to increased fat mass and weight gain, which, if you’re looking to lose weight, are probably not in the books. In females, research suggests that selenium plays a key role in follicular development and ovarian function, as well as a potential role in placental health 2.
Cognitive health
If you’re looking for sharper cognitive function, selenium is essential. Because of its role as an antioxidant, it’s important for reducing levels of oxidative stress. Reactive species (RS) are generated during the normal course of cellular metabolism, and because of its composition and physiology, the brain is particularly susceptible to oxidative stress 5.
Cellular protection
Selenium’s antioxidant properties are perhaps one of the most notable roles of this mineral.
Selenium functions to neutralize free radicals caused by environmental toxins, exercise, food, and normal metabolic processes that can harm cells and cause long-term damage, along with increase levels of oxidative stress and inflammation—both of which are involved in the pathology of multiple chronic diseases.
It’s a key component of some of the most critical antioxidant enzymes, including glutathione peroxidase (GPx), thioredoxin reductase (TrxR), and iodothyronine deiodinases (IDD) 6.
Thyroid function
The thyroid is the master gland that controls your metabolism, and if your thyroid isn’t functioning properly, losing weight is going to be a huge challenge. Low thyroid function and hormone levels can result in hypothyroidism and subsequent weight gain.
However, the thyroid requires sufficient levels of thyroid hormones to run optimally. Research shows that selenium deficiency may compromise thyroid hormone metabolism and exacerbate hypothyroidism 3.
Selenium is not only required for the conversion of T4 to its active form, T3, but it's also incorporated into iodothyronine deiodinases and plays a vital role in thyroid hormone metabolism 7.
Can Selenium Boost Weight Loss?
If you’re looking for weight loss, selenium may be a beneficial supplement to add to your stack, but you have to keep in mind that it’s not a fat burner, it’s not a weight loss supplement, and it’s not something that will light your metabolic fat-burning fire. Selenium is a trace mineral that plays key roles in supporting optimal body function, including of the thyroid, so it may have a more indirect role in weight loss than something like a fat burner or a thermogenic pre-workout.
Selenium and thyroid function
When it comes to selenium and weight loss, most of the research revolves around the role of selenium in supporting thyroid function. Of all organs in the human body, the thyroid contains the highest selenium content per gram of tissue due to the expression of specific selenoproteins, of which some play a role in thyroid hormone metabolism while others play an antioxidant defense role 8. The specific selenoproteins that play a role in thyroid function include:
Deiodinases
Type 1 deiodinase (D1): Conversion of T4 into T3 and rT3, and T3 into rT3 or T2; localized in the liver, kidneys, thyroid gland, and pituitary gland
Type 2 deiodinase (D2): Conversion of T4 into T3, and T3 into T2; localized in the thyroid gland, CNS, pituitary gland, skeletal, and heart musclesPeople diagnosed with hypothyroidism tend to have a low basal metabolic rate (BMR), which means that calorie burn and energy use are lower than those with normal thyroid function. As such, despite eating well and exercising, you may not be burning calories as quickly and the weight may start to pile on.And since selenium is such an important mineral for thyroid function, getting adequate amounts may help keep your thyroid in check, which may prevent weight gain and a sluggish metabolism associated with hypothyroidism and support weight loss.While there is by no means a solid connection between selenium and weight loss, there are a couple of supporting studies.A 2019 study looked at the effects of selenium supplementation on TSH and interferon-γ inducible chemokines (CXCL9, CXCL10, and CXCL11) levels in patients with subclinical hypothyroidism (Hashimoto’s thyroiditis) 9.
Participants received 83mcg of selenomethionine per day orally for 4 months. Results showed that normal thyroid function was restored in 22 of 45 participants (almost 49 percent) with more than 80% of the participants maintaining normal thyroid function 6 months after stopping selenium supplementation.What’s more, a small 2020 study with 37 overweight adults found that people following a calorie-restricted diet and supplementing with selenium lost more weight than the people only following the diet 10.
Final Thoughts
While it may not help you drop 20 pounds in 6 months, adding selenium into your diet can have a profound impact on more than just your metabolism.
It’s needed for various functions critical to overall health, but especially for the thyroid. And if you’re looking to lose weight, optimal thyroid function is going to be a deciding factor, as it’s the master controller of how your body uses energy.
References
- B Moghadaszadeh, AH Beggs. Selenoproteins and their impact on human health through diverse physiological pathways. Physiology (Bethesda). 2006;21:307-315.
- IH Qazi, C Angel, H Yang, et al. Selenium, Selenoproteins, and Female Reproduction: A Review. Molecules. 2018;23(12):3053.
- MP Rayman. The importance of selenium to human health. Lancet. 2000;356(9225):233-241.
- R Scott, A MacPherson, RW Yates, B Hussain, J Dixon. The effect of oral selenium supplementation on human sperm motility. Br J Urol. 1998;82(1):76-80.
- D Gashu, BJ Stoecker. 2019. Selenium and Cognition: Mechanism and Evidence. In: Preedy V., Patel V. (eds) Handbook of Famine, Starvation, and Nutrient Deprivation. Springer, Cham. https://doi.org/10.1007/978-3-319-40007-5_21-2
- U Tinggi. Selenium: its role as antioxidant in human health. Environ Health Prev Med. 2008;13(2):102-108.
- M Ventura, M Melo M, F Carrilho. Selenium and Thyroid Disease: From Pathophysiology to Treatment. Int J Endocrinol. 2017;2017:1297658.
- A Drutel, FArcham beaud, P Caron. Selenium and the thyroid gland: more good news for clinicians. Clin Endocrinol (Oxf). 2013;78(2):155-164.
- I Pirola, M Rotondi, A Cristiano, et al. Selenium supplementation in patients with subclinical hypothyroidism affected by autoimmune thyroiditis: Results of the SETI study. Endocrinol Diabetes Nutr (Engl Ed). 2020;67(1):28-35.
- E Cavedon, J Manso, I Negro, et al. Selenium Supplementation, Body Mass Composition, and Leptin Levels in Patients with Obesity on a Balanced Mildly Hypocaloric Diet: A Pilot Study. Int J Endocrinol. 2020;2020:4802739.
