What is selenium and what does it do?

Selenium is an essential trace mineral used to build selenoproteins that support antioxidant defense, thyroid hormone metabolism, and immune function.

What foods are high in selenium?

Brazil nuts are a concentrated source, and selenium is also found in seafood, meats, eggs, dairy, and grains (amounts vary by soil content).

How much selenium should I take per day?

Many adults aim around 55 mcg/day from diet and supplements combined, and supplemental intakes are often kept within about 55–200 mcg/day unless a clinician advises otherwise.

What are signs of selenium deficiency?

Deficiency can contribute to impaired thyroid function and weakened immune response, and may be more likely with very low dietary intake or certain medical conditions.

Can you take too much selenium?

Yes. Excess intake can cause selenium toxicity (selenosis), with symptoms such as gastrointestinal upset, hair or nail changes, and a garlic-like breath odor; avoid high-dose use without medical guidance.

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Selenium

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Selenium is an essential trace mineral crucial for antioxidant defense, thyroid function, and immune health.

Cancer-inhibitor Essential Nutrient Antioxidant Immune Booster

Doz aralığı

55–200 µg

Once daily or split with meals.

Gelir

Take with or without food; taken with food may improve absorption slightly and reduce GI discomfort.

Yağda çözünmez.

En iyi zaman

Morning or with main meals is common.

Açıklama

Selenium is an essential micronutrient that acts as a cofactor for selenoproteins with antioxidant, thyroid, and immune regulatory functions. It is naturally found in foods such as Brazil nuts, seafood, and grains. Both deficiency and excess can have health consequences, making appropriate intake important.

Avantajlar

Kanıt derecesi ile ana etkiler

Moderate

Kanıtla ilgili not

Evidence for selenium's role in thyroid health and immune support is moderate; evidence for cancer prevention is mixed.

Supports Thyroid Health

Strong

Selenium is vital for the synthesis and metabolism of thyroid hormones and helps protect the thyroid gland from oxidative damage.

Özellikle ilgili olduğu kişiler: People with thyroid disorders · Adults with low dietary selenium

S1 · American Journal of Clinical Nutrition S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet S5 · EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for selenium

Antioxidant Protection

Moderate

As a component of selenoproteins such as glutathione peroxidase, selenium helps neutralize harmful free radicals, supporting cellular and DNA integrity.

Özellikle ilgili olduğu kişiler: Adults · Older adults

S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet S6 · Examine.com – Selenium

Immune System Support

Moderate

Adequate selenium is associated with optimal immune response, as it modulates inflammation and enhances the function of white blood cells.

Özellikle ilgili olduğu kişiler: People at risk of infection · Older adults

S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet

May Lower Risk of Some Cancers (Mixed Evidence)

Mixed

Observational studies suggest that higher selenium status may lower the risk of certain cancers (e.g., prostate, lung, colorectal), but data from supplementation trials are inconsistent.

Özellikle ilgili olduğu kişiler: General population

S3 · British Journal of Nutrition S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet

Güvenlik ve Uyarılar

Önemli güvenlik bilgileri ve bilinen riskler

Sadece eğitim amaçlıdır • tıbbi tavsiye değildir

Selenium is safe at recommended dosages, but excess intake can cause toxicity; use caution with chronic supplementation or if in a high-risk group.

Uyarılar

High selenium intake (>400 mcg/day) can cause selenosis with symptoms such as gastrointestinal distress, hair loss, nail brittleness, and neurological abnormalities.
Individuals with kidney dysfunction, certain skin conditions, or those taking anticoagulants should consult a healthcare provider before supplementing.
Selenium supplements should be avoided or used with caution in individuals with known hypersensitivity to selenium compounds.
Do not exceed 400 mcg of selenium per day to avoid risk of selenosis.
Avoid selenium supplementation if you have known hypersensitivity to selenium compounds.
Use selenium supplements only under medical supervision if you are taking anticoagulants, undergoing chemotherapy, or have severe skin conditions.
Monitor selenium intake in individuals with chronic kidney disease or iodine deficiency.

İlaçlarla bilinen etkileşimler

Anticoagulants (increased bleeding risk)
Chemotherapy drugs (potential altered efficacy/toxicity)

Kontrendikasyonlar / özel dikkat gerektiren gruplar

Known hypersensitivity to selenium or selenium compounds
Acute selenosis or chronic excessive selenium intake

etkileşimler

Etkin madde ↔ takviye / ilaç / gıda arasındaki önemli etkileşimler

Selenium interacts with certain drugs and nutrients, potentially altering absorption or effects.

Selenium may increase bleeding risk when taken with anticoagulant medications.

drug · Anticoagulants

CautionModerate

Neden

Some forms of selenium may influence blood clotting or platelet function.

Öneri

Use only with clinician supervision if taking anticoagulants.

S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet S4 · WebMD Selenium Monograph

Selenium may interact with chemotherapy drugs and affect treatment efficacy or toxicity.

drug · Chemotherapy drugs

CautionLimited

Neden

Possible interactions between selenium and some chemotherapeutic agents have been reported; clinical significance is unclear.

Öneri

Consult an oncologist before selenium supplementation during chemotherapy.

S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet

Selenium status influences iodine metabolism and thyroid hormone synthesis.

nutrient · Iodine

MonitorModerateIodine

Neden

Adequate selenium is necessary for proper thyroid hormone metabolism, especially in areas of marginal iodine intake.

Öneri

Ensure proper intake of both nutrients, especially in regions with iodine deficiency.

S1 · American Journal of Clinical Nutrition S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet

Etki mekanizmaları

Nasıl çalıştığına dair kısa açıklamalar

Cofactor in selenoproteins for antioxidant defense

Selenium acts as a cofactor for glutathione peroxidase and other enzymes that reduce cellular oxidative stress, protecting lipids, proteins, and DNA from damage.

S2 · NIH Office of Dietary Supplements (ODS) Selenium Fact Sheet S6 · Examine.com – Selenium