Abstract
Thyroid has a key role in energetic metabolism and its activity is influenced by caloric intake: reducing in prolonged fasting and malnutrition. Iodine deficiency may induce severe thyroid diseases; if it occurs during growth, it results in permanent disabling systemic damage. For this reason, local governments and WHO promote programs of iodine supplementation. Goitrogenic foods induce clinical damage only if ingested in great amounts and in case of iodine deficiency. The relationship among diet, foods and thyroid function is complex whether it regards iodine intake or its absorption and utilization favoring inhibiting nutrients. People with thyroid dysfunction should change some dietetic habits, choosing synergic nutrient-rich foods and reducing the antagonist ones; they should reduce fats for slowing their cellular oxidation rate and introduce proteins and carbohydrates at 20 and 55% of total energy intake, respectively.