What is Selenium?

Definition:
Selenium is a trace mineral essential for human health. It is a powerful antioxidant that supports various physiological processes, including thyroid function, immune system regulation, and cellular protection.
Discovery:
Identified in 1817, selenium was initially considered toxic but later recognized as a vital nutrient in small amounts.

What Types of Selenium Are There, and What Do They Do?

Organic Selenium:
Found in foods like Brazil nuts and seafood. The two primary organic forms are selenomethionine and selenocysteine, which are bioavailable and easily utilized by the body.
Inorganic Selenium:
Includes selenite and selenate, often used in supplements and fortifications. They must be converted to organic forms in the body to be beneficial.

Daily Requirements for Selenium

Infants (0-12 months): 15-20 mcg/day
Children (1-8 years): 20-30 mcg/day
Adolescents (9-18 years): 40-55 mcg/day
Adults: 55 mcg/day
Pregnant Women: 60 mcg/day
Breastfeeding Women: 70 mcg/day
Upper Limit: 400 mcg/day (to prevent toxicity)

What Does Selenium Do in Our Body?

Antioxidant Protection:
Selenium is a key component of glutathione peroxidase, an enzyme that protects cells from oxidative stress.
Immune Support:
It strengthens the immune system by modulating inflammatory responses and fighting infections.
Thyroid Hormone Regulation:
Selenium is critical for converting thyroxine (T4) to the active form, triiodothyronine (T3).

Symptoms of Selenium Deficiency

Physical Symptoms:
Hair loss, brittle nails, muscle weakness, and fatigue.
Thyroid Symptoms:
Hypothyroidism, goiter, and reduced thyroid hormone production.
Immune Symptoms:
Increased susceptibility to infections.
Reproductive Symptoms:
Infertility in both men and women.

What Does Selenium Do for Our Thyroid Pathway?

Conversion of T4 to T3:
Selenium-dependent enzymes, iodothyronine deiodinases, are essential for this process.
Protection Against Thyroiditis:
Selenium reduces inflammation and oxidative damage in thyroid tissues.
Blocks RT3 and reverses it:
Selenium is key in helping Reverse T3 go back to T3 in useable form.
Support for Autoimmune Conditions:
Studies show selenium supplementation can reduce thyroid antibodies in Hashimoto's thyroiditis.

What Does Selenium Do for Our Liver?

Detoxification:
Selenium supports the liver’s ability to neutralize toxins through glutathione production.
Protection from Oxidative Stress:
It prevents liver damage caused by free radicals and environmental toxins.
Enzyme Functionality:
Selenium aids the functioning of enzymes essential for liver health, like thioredoxin reductase.

What Does Selenium Do for Our Gut?

Gut Microbiome Balance:
Selenium supports the growth of beneficial gut bacteria, enhancing gut health.
Barrier Protection:
It helps maintain the integrity of the gut lining, reducing the risk of leaky gut.
Inflammation Reduction:
Selenium lowers gut inflammation by modulating immune responses.

Physical Ailments That Affect Selenium Levels

Chronic Illnesses:
Conditions like Crohn's disease and celiac disease reduce selenium absorption.
Kidney Disease:
Dialysis patients often experience selenium depletion.
Digestive Disorders:
Malabsorption syndromes can lead to selenium deficiency.

Foods That Impact Selenium Absorption

High Phytate Foods:
Grains and legumes contain phytates that bind to selenium, reducing its absorption.
Excess Calcium or Iron:
Competes with selenium for absorption in the gut.

Medications That Impact Selenium

Antacids and Proton Pump Inhibitors:
Reduce stomach acid, impairing selenium absorption.
Corticosteroids:
Long-term use can lead to selenium depletion.
Chemotherapy Drugs:
Lower selenium levels due to increased oxidative stress.

Natural Supplements That Negatively Impact Selenium

High Doses of Zinc or Iron:
Interfere with selenium absorption when taken simultaneously.
Excess Vitamin C:
In very high doses, it can degrade selenium compounds.

Heavy Metals That Impact Selenium

Mercury:
Binds to selenium, rendering it unavailable for biological use.
Cadmium and Arsenic:
These metals disrupt selenium metabolism and increase oxidative stress.

Testing for Selenium

Blood Tests:
Serum selenium levels indicate short-term status.
Hair or Nail Analysis:
Reflect long-term selenium exposure.
Functional Tests:
Measure glutathione peroxidase activity to assess selenium functionality.

Nutrients Required for Selenium Absorption

Vitamin E:
Enhances the antioxidant effects of selenium.
Sulfur Amino Acids:
Found in protein-rich foods, they support selenium metabolism.

Foods High in Selenium

Brazil Nuts:
The richest natural source (68–91 mcg per nut).
Seafood:
Tuna, sardines, and shrimp.
Organ Meats:
Liver and kidneys.
Eggs and Dairy Products:
Moderate selenium content.

A Recipe High in Selenium

**Brazil Nut and Tuna Salad**

Ingredients: 1 can of tuna, 6 Brazil nuts (chopped), mixed greens, cherry tomatoes, olive oil, and lemon juice, plus garnishes of your choosing.
Method: Combine ingredients in a bowl and drizzle with olive oil and lemon juice. Enjoy a selenium-packed meal!

Other Random Information About Selenium

Geographical Variations:
Selenium content in foods depends on the soil where they are grown. Selenium-rich soil produces selenium-rich crops.
Selenium and Cancer:
Some studies suggest selenium may reduce cancer risk by protecting cells from DNA damage.
Excess Selenium Risks:
Over-supplementation can lead to selenosis, causing symptoms like garlic breath, nausea, and neurological issues.

Disclaimer: The information provided in this article is for educational purposes only and is not intended to diagnose, treat, or cure any medical condition. Always consult with a qualified healthcare professional before making any changes to your diet, lifestyle, or treatment plan. Individual needs may vary, and what works for one person may not be suitable for another.

The Thyroid and Selenium