Iodine deficiency manifests as hypothyroidism — fatigue, weight gain, cold sensitivity, dry skin, and hair loss. In severe cases, goiter (thyroid enlargement) develops. During pregnancy, iodine deficiency can impair fetal brain development and cause cretinism. Mild deficiency is surprisingly common in Estonia.

Yes, excess iodine (over 1,100 mcg per day for adults) can paradoxically suppress thyroid function, causing both hypo- and hyperthyroidism. Seaweed supplements can contain very high amounts of iodine. Those with Hashimoto's thyroiditis and Graves' disease need to be especially cautious.

Iodized salt is a good iodine source — half a teaspoon covers roughly half the daily requirement. However, not all food manufacturers use iodized salt, and reducing salt for health reasons can leave iodine intake insufficient. A supplement is the most reliable way to ensure adequate iodine, especially for pregnant women.

Yes, if fatigue stems from subclinical hypothyroidism due to iodine deficiency, supplementation can noticeably improve energy levels. Thyroid hormones regulate cellular energy production throughout the body. If thyroid function is normal, additional iodine will not provide an energy boost.