Nutritionist Olga Ugryumova listed the groups of chemicals that can cause disorders in the thyroid gland.
It depends on how harmoniously the thyroid gland works without exaggeration, the health of the whole organism and our well-being. Certain chemicals can negatively affect the thyroid gland by destroying its hormones. These are fluorine, triclosan, styrenes, nitrates, perchlorate and thiocyanate. If possible, they should be avoided.
“A person who leads a non-ecological lifestyle encounters these substances every day, without even suspecting how dangerous they are for the body. If you already have thyroid diseases, it is extremely important to protect yourself from these substances,” the expert comments.
Sources of chemicals that disrupt the functioning of the thyroid gland are, for example, out-of-season vegetables, fruits and greens.
They contain nitrates. To be on the safe side, only buy seasonal produce.
Triclosan is contained in creams, cosmetics, antiseptics. The danger is that triclosan is not excreted from the body, settling on the skin and penetrating into the bloodstream.
Interacting with the sun, it forms toxic dioxins, poisoning the body. Try to use natural cosmetics.
Hazardous fluoride compounds may be present in water and toothpaste. Carefully study the composition of toothpastes.
The source of perchlorate can be water from wells and groundwater. Perchlorates are dangerous because they inhibit the activity of the thyroid gland. 
Olga Ugryumova Health Nutritionist, nutritionist