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Selenium Chelate

Also known as: Selenium, Se, Selenomethionine, Selenocysteine

Overview

Selenium is an essential trace element vital for various physiological functions. It is incorporated into selenoproteins, which play critical roles in antioxidant defense, thyroid hormone metabolism, and immune function. Selenium is naturally found in foods such as Brazil nuts, seafood, and organ meats. Supplement forms include selenomethionine (an organic form) and sodium selenite (an inorganic form). Selenium's primary uses involve supporting immune function, reducing oxidative stress, and potentially lowering the risk of certain chronic diseases. Research suggests that adequate selenium intake is associated with reduced all-cause mortality and improved outcomes in specific conditions like autoimmune thyroiditis. However, maintaining selenium levels within the recommended range is crucial, as excessive intake can lead to toxicity.

Benefits

Selenium offers several evidence-based health benefits. It enhances immune function by increasing natural killer cell activity, as shown in a meta-analysis of nine trials. High dietary selenium intake is associated with a reduced risk of all-cause mortality (RR: 0.79, 95% CI: 0.73, 0.85 per 10 μg/day increment) and may reduce the risk of certain cancers, including liver and pancreatic cancer. Selenium supplementation can also improve outcomes in autoimmune thyroid diseases by reducing anti-thyroid peroxidase antibodies. Furthermore, it may improve sperm quality in men and, as part of antioxidant mixtures, reduce cardiovascular disease mortality. The clinical significance of these benefits varies depending on the specific health outcome and population.

How it works

Selenium primarily functions through its incorporation into selenoproteins, such as glutathione peroxidase, which act as antioxidants, protecting cells from oxidative damage. These selenoproteins influence redox balance and cellular protection. Selenium supports immune function by modulating immune cell activity and cytokine production. It also plays a crucial role in thyroid hormone metabolism by converting thyroxine (T4) to triiodothyronine (T3), the active form of thyroid hormone. Selenium is generally well-absorbed, especially in organic forms like selenomethionine, facilitating its incorporation into selenoproteins and subsequent biological activities.

Side effects

Selenium is generally safe when consumed within the recommended dietary allowance (RDA), but excessive intake can lead to adverse effects. Common side effects at high doses include nausea, diarrhea, and a metallic taste. Uncommon side effects (1-5%) may involve hair loss and skin lesions. Rare but severe side effects include selenosis, characterized by symptoms like garlic breath, tremors, and kidney damage. Selenium may interact with certain medications, such as blood thinners. High doses are contraindicated in pregnancy and lactation due to potential toxicity. Individuals with kidney disease should exercise caution due to the increased risk of toxicity. The Tolerable Upper Intake Level (UL) for adults is 400 μg/day to mitigate these risks.

Dosage

The minimum effective dose of selenium for general health support is typically around 50-100 μg/day. Optimal dosage ranges from 50-200 μg/day, depending on specific health goals and the individual's health status. The Tolerable Upper Intake Level (UL) is 400 μg/day for adults. No specific timing is recommended; consistent daily intake is advised. Organic forms like selenomethionine may be better absorbed than inorganic forms. Absorption is generally good but may be influenced by dietary factors. It's crucial to ensure intake does not exceed the UL to avoid toxicity.

FAQs

Is selenium safe to take daily?

Selenium is safe when taken daily within the recommended dietary allowance (RDA) and below the Tolerable Upper Intake Level (UL) of 400 μg/day for adults. Exceeding this limit can lead to toxicity.

What are the best food sources of selenium?

Excellent food sources of selenium include Brazil nuts, seafood (such as tuna and shrimp), organ meats (like liver), and sunflower seeds. Incorporating these into your diet can help meet your selenium needs.

Can selenium help with thyroid problems?

Selenium plays a role in thyroid hormone metabolism and may improve outcomes in autoimmune thyroid diseases by reducing anti-thyroid peroxidase antibodies. Consult with a healthcare provider for personalized advice.

What are the symptoms of selenium toxicity?

Symptoms of selenium toxicity (selenosis) include garlic breath, gastrointestinal issues, hair loss, skin lesions, neurological problems, and, in severe cases, kidney damage. Seek medical attention if these symptoms occur.

Does selenium interact with any medications?

Selenium may interact with certain medications, such as blood thinners. Consult with a healthcare provider if you are taking any medications to avoid potential adverse interactions.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/36789948/ – A systematic review and meta-analysis of 9 trials found that selenium supplementation increased natural killer (NK) cell activity but did not significantly affect other immune parameters. The studies, conducted primarily in North America and Europe over 8-48 weeks, showed heterogeneous results due to varying trial designs, leading to a moderate quality assessment.
https://pubmed.ncbi.nlm.nih.gov/33053149/ – A systematic review and meta-analysis of 43 RCTs lasting ≥24 weeks indicated that antioxidant mixtures containing selenium reduced the risks of cardiovascular disease and all-cause mortality. The study's high quality is attributed to its robust methodology, although variability in study designs and populations was noted.
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1263853/full – An umbrella review of meta-analyses found that high dietary selenium intake was associated with reduced all-cause mortality and certain disease risks. The study's quality was rated as moderate to high due to its comprehensive analysis, but it noted heterogeneity across the included studies.
https://www.alzdiscovery.org/uploads/cognitive_vitality_media/Selenium_1.pdf – This resource provides an overview of selenium, highlighting its role as an essential trace element with antioxidant properties. It discusses selenium's potential benefits for cognitive health and overall well-being, emphasizing the importance of maintaining adequate selenium levels through diet or supplementation.
https://www.webmd.com/vitamins/ai/ingredientmono-1003/selenium – WebMD provides general information about selenium, including its uses, potential benefits, and safety considerations. It outlines the importance of selenium for various bodily functions and highlights the need to adhere to recommended dosages to avoid adverse effects.