Nutrition Market

Selenium Supplements in Australia


Selenium is an essential trace mineral that plays a critical role in various aspects of health. It acts as an antioxidant, supports immune function, and enhances metabolic processes in the body. Selenium is found naturally in soil and passed into the food chain, where it accumulates in foods like nuts, seafood, meat and eggs. However, selenium levels in soil vary greatly depending on geographical location. Parts of Australia and New Zealand are known to have low concentrations of selenium (Thomson, 2004). This makes selenium deficiency more prevalent in these areas. Supplementing with selenium can help fill nutritional gaps and provide health protective benefits.

What is Selenium?

Selenium is a trace mineral and essential micronutrient for humans. It is classified as a nonmetal chemical element with the atomic number 34 on the periodic table (Levander & Burk, 2006). Selenium was discovered in 1817 by Swedish chemist Jöns Jakob Berzelius. He named it after the Greek moon goddess Selene.

In terms of properties, selenium exists in both organic and inorganic forms. The organic forms include selenomethionine, selenocysteine and methylselenocysteine. Inorganic forms include selenite and selenate. Selenium is most commonly found as selenocysteine, which gets incorporated into selenoproteins. There are over 30 known selenoproteins in the human body that carry out essential biological functions (Papp et al., 2007).

Benefits of Selenium

Antioxidant Properties

One of the main benefits of selenium is its role as a powerful antioxidant. It helps neutralise free radicals and prevent oxidative damage to cells (Rayman, 2012). This antioxidant function is carried out through selenoproteins like glutathione peroxidases.

Supports Immune System

Selenium plays a key role in modulating immune response and suppressing excessive inflammation (Huang, Rose & Hoffmann, 2012). It helps activate immune cells and supports antibody production. This is why selenium deficiency can increase susceptibility to infections.

Enhances Metabolic Function

Selenium is essential for proper metabolic functioning. It is required for the activation of thyroid hormones and helps convert the inactive form to the active form. Selenium deficiency impairs this conversion which can lead to hypothyroidism (Drutel, Archambeaud & Caron, 2013).

Selenium Deficiency

Prevalence and Causes

Selenium deficiency is common in many parts of the world, including Australia and New Zealand. This is primarily attributed to low levels of bioavailable selenium in the soil in these countries (Thomson, 2004). Selenium concentrations in soil range greatly - from 0.01 to over 1000 μg/g depending on the geographical region.

Since crops and livestock obtain selenium from the soil, low soil selenium translates to low selenium content in grains, vegetables, meat and dairy. People living in these regions are at a higher risk of selenium deficiency unless they supplement or consume imported foods.

Symptoms of Selenium Deficiency

Physical Symptoms

  • Muscle weakness and pain
  • Joint pain
  • Hair loss
  • Changes in fingernails like white spots or brittle nails
  • Impaired immune function

Cognitive Symptoms

  • Irritability
  • Lethargy
  • Impaired cognitive function
  • Mood disorders like anxiety and depression

Risk Factors for Selenium Deficiency

Dietary Restrictions

People following restricted diets like vegan or vegetarian diets are at a higher risk for selenium deficiency. Plant-based diets provide limited dietary selenium since the main food sources are animal products like seafood, meat and eggs.

Certain Health Conditions

  • Gastrointestinal disorders like Crohn's disease and ulcerative colitis can impair selenium absorption from food.
  • Kidney disease increases selenium excretion leading to losses.
  • HIV is associated with declined selenium levels.

Selenium Supplements

Why Selenium Supplements Are A Viable Solution

Given the high rates of deficiency and the lack of adequate dietary sources of selenium in Australia and New Zealand, supplementation is often necessary to meet needs. Selenium supplements help:

  • Boost dietary intake where food sources are inadequate
  • Correct nutritional deficiencies
  • Provide antioxidant and immune boosting benefits

Features and Benefits of Selenium Supplements

Selenium supplements are available in various forms like selenomethionine, sodium selenite and selenium-enriched yeast. The two major forms available are:

  • Selenomethionine: This is the preferred supplemental form as it gets readily absorbed and incorporated into body tissues. Our selenomethionine supplements provide highly bioavailable organic selenium.
  • Sodium Selenite: This inorganic form is more concentrated in selenium but does not get stored in tissues as efficiently as selenomethionine. Our high-quality selenite supplements offer antioxidant benefits.

Both forms provide the key benefits of selenium:

  • Boosts antioxidant activity
  • Enhances immune function
  • Supports thyroid health
  • Promotes mental wellbeing
  • Protects heart, liver and prostate health

How To Choose A High-Quality Selenium Supplement

When purchasing a selenium supplement in Australia, ensure:

  • The supplement provides an adequate dosage of 50-200 mcg selenium to meet nutritional needs without exceeding the upper limit.
  • The manufacturer tests for purity, potency and safety. Third party testing certification is ideal.
  • No unnecessary fillers, flavors or additives are included.

Selenium and Thyroid Health

Overview of the Connection

There is a well-established link between selenium and optimal thyroid function. Selenium plays a critical role in thyroid hormone metabolism and production. Selenium deficiency can negatively impact thyroid health and is associated with thyroid disorders like Hashimoto's and Graves' disease (Köhrle et al., 2019).

The Role of Selenium in Thyroid Function

Explanation of How Selenium Aids Thyroid Function

Selenium is required for the proper functioning of iodothyronine deiodinases - enzymes that convert the inactive thyroid hormone T4 into the active form T3. It also recycles iodine in the thyroid gland to maintain optimal levels. Selenium deficiency can reduce the conversion of T4 to T3 leading to hypothyroidism.

Selenium also helps protect the thyroid tissue from damage by free radicals and autoimmune attacks. Patients with autoimmune thyroid disease like Hashimoto's tend to have lower selenium levels (Drutel et al., 2013).

Studies Supporting Selenium's Role in Thyroid Health

Multiple studies demonstrate the benefits of selenium for thyroid function:

  • A study on New Zealand women with postpartum thyroiditis showed 200 mcg/day selenium reduced inflammation and autoimmune activity (Negro et al., 2007).
  • A 3-month trial in Germany found selenium supplementation decreased anti-thyroid antibodies in patients with Hashimoto's disease (Duntas et al., 2003).
  • A meta-analysis reported selenium supplementation significantly improved thyroid function and reduced thyroid antibody levels in patients with Hashimoto's (Toulis et al., 2014).

Using Selenium Supplements for Thyroid Health

Guidelines on Supplementing with Selenium for Thyroid Health

The recommended dosage of selenium supplements for supporting thyroid health is 100-200 mcg per day. Higher doses above 400 mcg are not recommended. It is ideal to supplement under the guidance of your healthcare practitioner. Selenium works best when combined with iodine and zinc supplements for thyroid health.

Precautions and Considerations

  • Selenium can interact with thyroid medications. Consult your doctor before supplementing if you are on thyroid hormone replacements like levothyroxine.
  • Take selenium supplements with food to minimise gastrointestinal side effects.
  • Avoid excessive selenium supplementation above 400 mcg daily as it can cause toxicity.
  • Inform your doctor about selenium supplementation if you have a thyroid disorder or take thyroid medications.

Frequently Asked Questions

What are the main food sources of selenium?

The richest dietary sources of selenium include Brazil nuts, seafood, organ meats, eggs, poultry and mushrooms. Grains grown in high selenium soil also provide good levels.

The recommended daily intake (RDI) of selenium for Australians is:

Age/Gender RDI
Infants 0-6 months 12 mcg/day
Infants 7-12 months 15 mcg/day
Children 1-3 years 25 mcg/day
Children 4-8 years 30 mcg/day
Boys 9-13 years 50 mcg/day
Boys 14-18 years 70 mcg/day
Girls 9-13 years 50 mcg/day
Girls 14-18 years 60 mcg/day
Men 19+ years 70 mcg/day
Women 19+ years 60 mcg/day
Pregnancy 14-50 years 65 mcg/day
Lactation 14-50 years 75 mcg/day

The upper limit is set at 400 mcg per day for adults.

Who is at risk of selenium deficiency?

Those eating plant-based diets or restricting animal products, people living in low soil selenium regions, those with chronic gastrointestinal issues, kidney disease patients and HIV patients are at a higher risk for selenium deficiency.

What are the side effects of selenium supplements?

Selenium supplementation above 400 mcg daily can potentially lead to selenium toxicity. Symptoms include hair loss, brittle nails, rash, nausea, irritability and nerve damage. Mild gastrointestinal distress can occur with high supplemental doses.

Can I take selenium with thyroid medications?

Selenium supplements can be taken safely with synthroid or levothyroxine but may improve their absorption. Inform your doctor before supplementing to monitor thyroid levels closely. Selenium should not be taken together with anti-thyroid medications.


In summary, selenium is an essential trace mineral that provides antioxidant, immune-boosting and thyroid supporting benefits. Selenium deficiency is common in Australia and New Zealand owing to low soil concentrations. Supplementing with bioavailable forms of selenium like selenomethionine can help increase intakes, correct deficiencies and promote optimal health. When supplemented within the recommended dosage range of 50-200 mcg daily, selenium is safe and well tolerated. It is especially beneficial for supporting thyroid health in those with autoimmune thyroid disorders. Always choose high-quality selenium supplements tested for purity, potency and safety.

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