Iodine deficiency
Linked to Iodine
Without enough iodine the thyroid cannot make hormones, slowing metabolism.
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.
Causes
- Low-iodine soils and diet
- No iodised salt
- Pregnancy demands
Symptoms
- Goitre (swelling in the neck)
- Fatigue and weight gain
- Feeling cold
- Dry skin
- Slowed thinking
What happens if untreated
- Hypothyroidism
- Serious developmental harm to a baby in pregnancy
Who is most at risk
- People in iodine-poor regions
- Pregnant people
- Those avoiding dairy and seafood
Prevention & sources
- Iodised salt
- Seafood, dairy and eggs
- Supplements in pregnancy if advised
Correcting it: foods, amounts & timing
Foods that help & safe amounts
- Iodised salt for everyday cooking (within normal salt limits)
- White fish and seafood — 1–2 times a week
- Dairy and eggs
- Around 150 µg/day for adults; seaweed can be very high in iodine, so keep it occasional
Energy and mood improve over a few weeks; a goitre shrinks slowly over months.
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.