Quick Summary

Sodium selenite is a chemical form of the essential trace element selenium used in dietary supplements. Selenium is required for important physiological functions including antioxidant defense and thyroid hormone metabolism. Sodium selenite serves as a source of selenium but is distinct from other forms such as selenomethionine.

What Is It?

Sodium selenite is an inorganic salt of selenium commonly used in dietary supplements to provide selenium, an essential micronutrient. Unlike organic forms of selenium such as selenomethionine, sodium selenite is a simple selenium compound and is one of several selenium forms used to help meet nutritional needs. It should be understood as a selenium source rather than a standalone nutrient with unique biological roles.

Main Functions in the Body

  • Contributes to antioxidant defense systems
  • Supports thyroid hormone metabolism
  • Plays a role in immune function

These functions are generally attributed to selenium itself and apply regardless of the chemical form consumed.

Recommended Intake and Upper Limit

The recommended dietary allowance (RDA) for selenium is established by authoritative health agencies and applies to all chemical forms of selenium, including sodium selenite. Similarly, a tolerable upper intake level (UL) exists for selenium to minimize the risk of adverse effects from excessive intake.

Specific values for RDA and UL vary depending on age, sex, and life stage. Individuals should consult official dietary guidelines or healthcare professionals for personalized recommendations.

Note: The intake and safety thresholds apply to selenium regardless of its chemical form, including sodium selenite.

Best Food Sources

Selenium naturally occurs in various foods, but sodium selenite is not found in foods per se. Common dietary sources of selenium include:

  • Brazil nuts
  • Seafood
  • Meats
  • Cereals and grains

These foods provide organic and inorganic forms of selenium, supporting overall nutritional selenium status.

Deficiency: Causes, Symptoms and Risk Groups

  • Risk Groups:
    • Individuals with low dietary selenium intake
    • People with malabsorption issues
    • Certain geographic populations living in selenium-poor soil regions
  • Signs and Symptoms:
    • Keshan disease (a cardiomyopathy)
    • Kashin–Beck disease (an osteoarthropathy)
    • Impaired immune function

Selenium deficiency symptoms arise regardless of the chemical form consumed. Correction of deficiency typically involves restoring overall selenium status rather than specific forms.

Supplement Forms

  • Sodium selenite is a common inorganic form used in selenium supplements.
  • Other selenium supplement forms include organic selenomethionine, selenate, and selenium-enriched yeast.

The choice of form depends on supplement formulation and intended use.

Absorption and Bioavailability

Sodium selenite is absorbed in the gastrointestinal tract. However, bioavailability may differ compared to organic selenium forms such as selenomethionine, which generally show higher bioavailability.

No specific enhancers or inhibitors of sodium selenite absorption were detailed in the evidence.

These differences may influence the efficiency of selenium status improvement when supplemented.

Potential Benefits: What Does the Evidence Say?

Correction of Selenium Deficiency

There is strong evidence that selenium supplementation, including sodium selenite, effectively corrects selenium deficiency and supports essential biological functions related to antioxidant defense, thyroid metabolism, and immunity.

However, direct comparisons establishing unique benefits or superior efficacy of sodium selenite over other selenium forms are lacking.

Side Effects and Toxicity

Excessive selenium intake from any source, including sodium selenite, can potentially lead to selenosis, a condition characterized by symptoms such as gastrointestinal distress and hair or nail changes.

Adhering to established tolerable upper intake levels for selenium is important to mitigate such risks.

No common side effects specific to sodium selenite were reported.

Drug and Nutrient Interactions

The supplied evidence did not specify particular drug or nutrient interactions involving sodium selenite. As with all supplements, caution is advised when used concurrently with medications or other nutrients, and consultation with healthcare providers is recommended.

Who Should Be Careful?

  • Pregnant or breastfeeding women should consult healthcare professionals before selenium supplementation.
  • Individuals with medical conditions including kidney disease, thyroid disorders, or iron overload disorders require caution.
  • People using prescription medications or other supplements should seek professional advice to avoid potential interactions.

Frequently Asked Questions

Is sodium selenite the best form of selenium supplement?
While sodium selenite is an effective selenium source, organic forms like selenomethionine often have higher bioavailability. The best form depends on individual needs and product formulations.
Can sodium selenite prevent illness?
Selenium is essential for normal immune and antioxidant functions, but there is no conclusive evidence that sodium selenite supplementation prevents specific diseases in healthy individuals.
Is there a risk of selenium toxicity with sodium selenite?
Excessive intake of selenium from any form, including sodium selenite, may cause toxicity symptoms. It is important to avoid exceeding recommended upper intake levels.
Can I get sodium selenite from food?
Sodium selenite as such is not present in foods; dietary selenium comes in various chemical forms naturally occurring in food.

Evidence Limitations

  • No specific clinical trial data differentiate the efficacy or safety of sodium selenite from other selenium forms.
  • There are no explicit European Union-authorized health claims for sodium selenite.
  • Further research is needed to clarify detailed safety profiles and clinical distinctions for sodium selenite supplements.

References

Disclaimer

This page provides general information about sodium selenite as a selenium source. It does not constitute medical advice. Individuals who are pregnant, breastfeeding, have medical conditions, or take medications should consult a healthcare professional before starting any supplement.

Last Reviewed

June 2024