Selenium is an essential trace mineral that plays a crucial role in supporting overall health and well-being. Although the body requires only small amounts, it helps support thyroid function, immune system health, and antioxidant defense.
Historically, selenium was not recognized as an essential nutrient until the mid-20th century. Before that, it was primarily known for its industrial applications and was even considered toxic. However, extensive research has since uncovered its importance in human nutrition and its vital role in maintaining several biological functions.
The History of Selenium in Human Health
The Discovery of Selenium
Selenium was first identified as a chemical element in 1817 by Swedish chemist Jöns Jacob Berzelius. While analyzing the byproducts of sulfuric acid production, he observed a previously unknown element with properties similar to tellurium. He named it selenium, derived from the Greek word Selene, meaning "moon."
Initially, selenium was considered toxic due to its industrial uses in glassmaking, electronics, and pigments. However, by the mid-20th century, scientists began to recognize its biological significance.
Key Milestones in Selenium Research:
✔ 1957 – Selenium was identified as an essential nutrient in animals.
✔ 1970s-1980s – Studies confirmed its role in antioxidant defense, thyroid health, and immunity.
✔ Present Day – Ongoing research explores selenium’s role in heart health, cognitive function, and overall well-being.
While early concerns about selenium toxicity were valid in cases of excessive exposure, it is now well understood that in appropriate amounts, selenium is a vital nutrient that can help support several bodily functions.
The Importance of Selenium in the Diet
Antioxidant Properties & Cellular Protection
Selenium is a key component of glutathione peroxidase, an enzyme that can help support the body's ability to manage oxidative stress.
✔ Helps neutralize free radicals, which may damage cells
✔ Works alongside vitamin E to help support antioxidant activity
✔ Can help promote overall immune function
Thyroid Function & Hormone Regulation
The thyroid gland contains one of the highest concentrations of selenium in the body. Selenium is essential for converting thyroxine (T4) into triiodothyronine (T3), the active form of the thyroid hormone.
✔ Helps regulate metabolism and energy levels
✔ Works with iodine to maintain thyroid balance
✔ Can help support hormonal function
Immune System Support
Adequate selenium intake can help support immune function by promoting the activity of white blood cells and other immune components.
✔ Helps support immune response in times of stress
✔ Plays a role in cellular repair and defense mechanisms
Heart & Brain Health
Selenium may help support cardiovascular function by promoting healthy circulation. Its antioxidant properties are also being studied for their potential role in brain function and cognitive health.
✔ May help support circulatory balance
✔ Plays a role in memory and cognitive well-being
How to Get Selenium in Your Diet
Since the body does not produce selenium, it must be obtained through dietary sources.
Top Selenium-Rich Foods
Animal-Based Sources:
✔ Seafood – Tuna, shrimp, salmon, and sardines contain selenium.
✔ Eggs – A convenient source of selenium along with protein.
✔ Poultry – Chicken and turkey contain moderate amounts of selenium.
Plant-Based Sources:
✔ Brazil Nuts – The richest natural source of selenium (should be eaten in moderation).
✔ Mushrooms – Shiitake and white button mushrooms contain selenium.
✔ Spinach – A nutrient-dense green with selenium and other minerals.
✔ Sunflower Seeds – Provide selenium along with vitamin E.
✔ Whole Grains – Brown rice, oats, and whole wheat contain selenium.
Selenium Bioavailability: Food vs. Supplements
Selenium is available in many dietary sources, but its absorption and effectiveness depend on the form in which it is consumed. The body can obtain selenium from both natural food sources and dietary supplements, though absorption rates may vary.
Selenium in Food
The bioavailability of selenium from whole foods is generally high, meaning the body can efficiently absorb and use it.
✔ Found in nuts, seafood, meats, eggs, dairy, and whole grains
✔ Absorbed alongside other nutrients for optimal utilization
✔ Soil quality affects selenium levels in plant-based foods
Selenium in Supplements
Supplements are available in various forms for individuals who may not get enough selenium through their diet.
✔ Provides a concentrated source of selenium
✔ Available in different forms to suit dietary needs
✔ Can be beneficial for those with dietary restrictions or specific health concerns
Diet vs. Supplementation: Which Is Better?
For most people, obtaining selenium through a balanced diet is ideal, as whole foods provide additional nutrients that help optimize selenium’s function. However, supplementation may be useful in cases where dietary intake is insufficient, such as in regions with low-selenium soil, restrictive diets, or specific health conditions.
Consulting a healthcare professional before adding selenium supplements is always recommended.
Frequently Asked Questions (FAQ) About Selenium
1. What is Selenium in Food?
Selenium is a trace mineral found naturally in many foods, including nuts, seafood, poultry, eggs, and whole grains.
2. What Foods Have Selenium in Them?
The richest sources include Brazil nuts, tuna, eggs, mushrooms, and whole grains.
3. How Can I Get More Selenium in My Diet?
✔ Include selenium-rich foods in daily meals.
✔ Choose whole, unprocessed foods for better nutrient absorption.
4. Are There Vegetables High in Selenium?
Yes, mushrooms, spinach, and sunflower seeds contain selenium
Conclusion
Selenium is an essential nutrient that can help support antioxidant function, thyroid health, immune response, and overall well-being. By incorporating selenium-rich foods into your diet, you can help maintain optimal levels naturally.
