Selenium deficiency
Linked to Selenium
Low selenium can affect the heart, thyroid and immune function.
Where it shows on the body
Rotate the figure and click a red marker to see the affected area. Internal organs open a 3D organ model.
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Causes
- Selenium-poor soils and diet
- Malabsorption
- Dialysis
Symptoms
- Fatigue
- Weak immunity
- Thyroid problems
- Hair and nail changes
- Muscle weakness
What happens if untreated
- Heart-muscle disease (Keshan)
- Joint disease in deficient regions
Who is most at risk
- People in low-selenium regions
- Those with malabsorption
Prevention & sources
- Brazil nuts, seafood, meat and eggs
- Supplements only if advised
Correcting it: foods, amounts & timing
Foods that help & safe amounts
- 1–2 Brazil nuts a day covers most needs (don't overdo it)
- Seafood, meat and eggs
- Around 55–70 µg/day; keep well below 400 µg/day
Time to see benefits
Immunity and energy improve over several weeks.
Sources & references
Symptoms overlap — testing matters
Most deficiency symptoms (fatigue, poor concentration, skin and hair changes) are shared across several nutrients and many unrelated conditions. A symptom on this page is a reason to investigate, not a diagnosis.
A GP can confirm or rule out a deficiency with a blood test and check for underlying causes such as absorption problems. Do not start high-dose supplements on suspicion alone — some nutrients are harmful in excess, and supplementing before testing can mask the underlying result.
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