David Christopher, M.H.

I receive so many calls from people suffering from low functioning thyroid, mostly women. So I will tell all of you what I tell them. First avoid substances that lower thyroid functioning. This category is headed by fluorine and its derivatives, followed closely by chlorine and bromine and their respective derivatives. These substances can be found ubiquitously in tap water, gardens, foods and many drugs.  In fact U.S. patent applications were actually submitted for fluorine based drugs that basically lowered thyroid functioning. Fluorine, bromine and chlorine compete with iodine for binding sites especially in the thyroid.  A lack of iodine or an inability to uptake iodine can lead to goiters and other cyst diseases such as fibrocystic breast disease and poly-ovarian cyst disease.
Other endocrine disruptors (iodine antagonists) would include pesticides, herbicides, bromides found in breads and soda beverages, alcohol, beta-blockers and anti-depressants (i.e. PROZAC).
Symptoms of iodine deficiency can include; puffy eyes, swollen tongue, tender breasts, fatigue, hair loss, mental distress and depression.
The next step, after avoiding iodine antagonists, is to build up iodine levels in the body by simply eating green leafy vegetables, potatoes (with peel), beans and cranberries. If one is 
greatly deficient in iodine then sea vegetables must be included- particularly kelp, which is natures highest source of iodine. An easy way to take kelp is in Dr. Christopher’s well balanced Thyroid Maintenance Formula. This is concentrated iodine rich food for any deficiency, not just thyroid health.
The government tried to resolve the goiter issue in the U.S.A. by mandating that iodine be added to bread and then salt. Now it is not a required addition to either so a deficiency can occur with junk diets, and is compounded with the addition of bromides to bread. It is always better to obtain nutrients like iodine from produce rather than as supplements or additives. 
Some natural foods such as cabbage and other members of the cruciferous family may slightly block the uptake of iodine. However, it is far worse to eat bread and drink fluoridated water, which is defiantly an iodine antagonist.
In conclusion, if you are always tired, losing your hair and have trouble keeping off extra weight do not despair. Simply build up your iodine levels with nourishing foods and stay away from antagonists like soda pop, bakery products (with bromides), alcohol, chemicals and drugs.
David Christopher is a Master Herbalist and the director of The School of Natural Healing. He also co-hosts the popular radio show “A Healthier You” and is a popular international teacher and lecturer.