by Joan Haynes, NMD
Many patients have come to the clinic taking large doses of iodine, in hope that it will improve their thyroid function and help with fatigue or weight gain. While iodine is critical to human health and proper thyroid function, too much of it can become toxic to the body. How many micrograms or milligrams should you be taking a day?
In my opinion, the RDI (Recommended Daily Intake)is set too low at 150 mcg per day. Iodine is probably safe at doses up to 1 mg per day, but a common supplement has 12.5 mg per capsule and people sometimes take 4 of them per day!! Note the difference between micrograms (mcg) and milligrams (mg). This is over 300 times the RDI and can lead to trouble.
What is Iodine
Iodine is a trace mineral “critical to human health. It forms the basis of thyroid hormones and plays many other roles in human biochemistry. While the thyroid gland contains the body’s highest concentration of iodine, the salivary glands, brain, cerebrospinal fluid, gastric mucosa, breasts, ovaries and a part of the eye also concentrate iodine. In the brain, iodine is found in the choroid plexus, the area on the ventricles of the brain where cerebrospinal fluid (CSF) is produced, and in the substantia nigra, an area associated with Parkinson’s disease.” 1
To understand the technical difference between iodine and iodide, read more here.
Symptoms of Low Iodine
Goiter (enlarged thyroid), hypothyroidism, intellectual disability, and cretinism (congenital hypothyroidism leading to stunted physical and mental development), fibrocystic breast disease, muscle pain. There is also some concern that low iodine levels permit the over-accumulation of other similar minerals called halides – floride, bromide, chloride which are ubiquitous in our environment.
Iodine Toxicity
Different people have different needs for minerals. If someone’s genetics come from an iodine-poor part of the world and suddenly they have a large increase in their intake, they may develop thyroid problems. This may occur because their thyroid has become very efficient at utilizing small amounts of iodine. In particular, they may develop iodine-induced hyperthyroidism.
Iodism (iodine poisoning) produces a brassy taste, runny nose, and acne-like skin lesions. It can also cause a goiter, the enlargement of the thyroid gland, thirst, diarrhea, weakness, and convulsions.
There aren’t good statistics on how common these side effects are, but one researcher and clinician who routinely uses up to 50 mg doses of daily iodine reports that side effects occur in less around 5 percent of patients. He reports hyperthyroidism, allergies, swelling of the salivary glands and thyroid.
There is a big debate going on in the alternative medicine community about iodine. If you’d like to read more about that read this article The Great Iodine Debate by Westin Price Foundation.
How to Use Iodine Safely
The Reference Daily Intake is 100-150 mcg per day. Many clinicians think this is too low. This will prevent goiters and other overt signs of deficiency but may not be adequate to prevent other conditions of iodine deficiency.
The average person, who is not using iodized salt, should take a multivitamin-mineral supplement with iodine in it. We should all also eat plenty of iodine rich foods.
IODINE RICH FOODS 4
| FOOD | AMOUNT OF IODINE | PORTION |
| Iodized salt | 45 mcg | 1/8 of a teaspoon |
| Seaweed/dried kelp | 19 – 2,984 mcg | 1 sheet dried |
| Cod (wild caught) | 99 mcg | 3 oz |
| Yogurt, whole, grassfed | 75 mcg | 1 cup |
| Egg | 24 mcg | 1 egg |
| Tuna | 17 mcg | 3 oz |
| Lima Beans | 16 mcg | 1 cup cooked |
| Corn | 14 mcg | ½ cup cooked |
| Green Peas | 6 mcg | 1 cup cooked |
| Bananas | 3 mcg | 1 medium |
The Bottom Line
Iodine doesn’t work by itself for thyroid health. Your thyroid also needs selenium, zinc, copper, magnesium, calcium and the amino acid tyrosine from protein. Using these nutrients along with iodine might prevent problems in cases where high doses of iodine might lead to thyroid problems.
If you are treating a low thyroid, then you want to make sure that if you do use larger doses that you are monitoring your thyroid through lab testing. Bottom line – I recommend sticking with microgram (mcg) dosages and including seaweed and dried kelp into your diet regularly.