Thyroid enlargement, or goiter, is one of the earliest and most visible signs of iodine deficiency. The thyroid gland enlarges due to continuous stimulation by TSH to produce thyroid hormones, but this is not possible because iodine is lacking for this purpose.
Goiter can lead to the following symptoms.
- Increase in the circumference of the neck
- The feeling of having a “lump” in the throat
- Difficulty breathing
- Difficulty swallowing
- Congestion in the visible veins of the neck
Adequate iodine intake will usually reduce the size of the thyroid gland – goiter. However, whether and to what extent the effects of hypothyroidism are reversible depends on the age of the individual. In mild cases of iodine deficiency, however, the above adjustment response may be sufficient to supply the body with enough thyroid hormones. In more severe cases of iodine deficiency, however, not enough hormones can be produced and hypothyroidism occurs, with the classic symptoms of hypothyroidism, depending on the severity of the deficiency:
- Fatigue
- Disinterest
- Increase in reaction time
- Lack of concentration
- Listlessness
- Sensitivity to cold
- Constipation
- Loss of appetite
- Weight gain
- Dry and cool skin
- Hoarse and deep voice
- Thinning hair
- Bradycardia (slowing of the heartbeat)
- Hypercholesterolemia (increased serum cholesterol levels).
- Cycle disorders in women
In children, thyroid problems can lead to a decline in academic performance and slowed physical and mental development. Iodine deficiency has the most unfavorable effects in the early years of life, where brain development takes place. If a young and developing brain is damaged by a deficiency of thyroid hormones, this damage is usually irreversible. Children in areas deficient in iodine had – according to a meta-analysis of 18 studies – an IQ 13.5 points lower than children in areas with adequate iodine supply.
Pregnant and lactating women have higher iodine requirements than the general population. Iodine deficiency during pregnancy can have serious effects on the mental development of the unborn child – in the most severe cases, congenital hypothyroidism can develop, also called cretinism.
In the elderly, poor performance is often the only symptom and is therefore often misdiagnosed and easily confused with general age-related changes. However, older people may also develop dementia due to deficient thyroid hormones, which – unlike senile dementia or Alzheimer’s disease – is reversible with iodine supplementation.
