Kelp and Iodine Side Effects When Treating Low Thyroid Function

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Learn of the difference between Iodine found in Kelp and that found in supplements. Not knowing the difference can result in Iodine overdose and your impaired health.

After having suffered with a sub-clinical slow thyroid condition for over 30 years and losing thousands of dollars to wrong medications, improper lab work and clueless physician diagnoses, this writer determined to self-diagnose and self-prescribe an alternative treatment. Enough was enough!

A desire to pray, ask God’s Wisdom and manage one’s own health led to the hidden root-cause of the health condition - Iodine insufficiency.  I also discovered what was the double-edge side effects of Kelp, a sea vegetable which possesses among the highest concentrations of Iodine known.

Surprise -- Iodized Table Salt Is Not Enough

Iodized table salt does not have sufficient amounts of Iodine to maintain health. Actually, commercial table salt has only trace amounts of Iodine - about 150 mcg per gram.  A search for higher amounts of Iodine found in sea salt led to another startling discovery -- most sea salt sold in grocery and many health food stores has had Iodine removed.

In 1924, the Morton Salt company first added iodine to salt after a successful public health campaign.  Unfortunately, according to recent FDA findings, researchers analyzed over 88 clinical samples of Iodized table salt -- less than half contained sufficient amounts of Iodine. (1)

Nutritional Benefits and Side Effects of Kelp or Iodine:

Kelp and sea vegetables in general are abundant in such vitamins and minerals such as:

Vitamins A , C and B-12.  Minerals found are calcium , manganese, iron, zinc, and selenium. However, sea vegetables are mostly known to have a rich content of Iodine. Containing an average of anywhere from 1,500 mcg - 2,500 mcg of Iodine per gram, the highest Iodine content is generally found in brown algae. Furthermore, according to the Institute for Traditional Medicine, red or green algae have somewhat lesser amounts than the brown variety of this Iodine-rich algae. (2)

However, as with many things in life, too much of even a good thing can be detrimental. Since Iodine is crucial in maintaining one’s health, logic would indicate that taking plenty of Iodine supplements PLUS Kelp is even better. Not so.

Following below are some unpleasant and many times dangerous side effects for overdosing on too much Kelp and/or Iodine. (3)

Light to moderate dizziness - (can also occur if Iodine insufficiency is present)

Severe constipation and/or diarrhea

Instability and unsteadiness

Blurry vision or double vision

Low and/or high blood pressure

Abdominal pain

Mouth dryness or burning sensation, nausea and vomiting

Fever, diarrhea, vomiting

Erratic heart palpitations, weak pulse and coma

May exacerbate both hypothyroidism/hyperthyroidism

So, then, just what are safe amounts of Kelp and Iodine which can be consumed? 

Unfortunately, this cannot be easily determined ; persons are individuals with individual needs and responses to supplements. However, the bare minimum of Iodine is a trace amount of 150 mcg. for adults, while the maximum daily amount has been set at 1,110 mcg. daily -- not indefinitely.

Also, remember that straight Iodine in tablet or liquid form and Kelp Iodine are not one and the same. Kelp will always tend to have much higher concentrations than plain Iodine.

Alternative Supplemental Sources of Iodine:

Food! Food! And more food! PLUS minimal amounts of Kelp/Iodine. (4)


Naturally, seafood of any kind is the primary source of most Iodine starting with saltwater fish at 6 mcg. per gram. Conversely, fresh water fish comes in with an average of 0.375 mcg. per gram. while poultry, beef and pork come in third with processed lunch meats being last. Surprisingly, despite extremely high salty taste, processed lunch meats indicate little Iodine content which has in all likelihood been removed from the salt.

Eggs/Dairy Products:

An excellent source of Iodine, eggs generally contain 1.6 mcg. per gram. Milk/ yogurt follow with  0.7 mcg. per gram with some cheeses, whole-mozarella being the highest, containing around 0.47 mcg per gram.

Veggies, Fruit and Nuts:

Among the lowest recorded food sources for Iodine are green leaf salad veggies providing 0.24 mcg per gram, and nightshade vegetables, such as tomatoes, eggplant and potatoes coming in with half that amount. Most in the nut family provide about 0.2 mcg per gram.

The All Time Champion of Iodine Food Sources...Kelp!

In a October 2004 issue of Thyroid journal, findings from a study of various Kelp species found interesting results. Nori, the popular sea veggie used to wrap sushi delicacies, was found to have the lowest amount of Iodine -- 16 mcg per gram. On the other hand, commercial Kelp salt substitutes commonly found in health food stores contained 8,100 approximately mcg., (1/4 tsp.), per gram and were the highest source of Kelp studied. (3)  Without any doubt, Iodine as found in Kelp and standalone Iodine are exceptional, reliable and safe sources of Iodine if used moderately and monitored carefully. Chooose wisely -- ( my favorite phrase these days...)

While this is not a health opionion, it is good advice. DO NOT DO AS THIS WRITER DID.

Do not eat large amounts of high Iodine content food - PLUS take double portions of liquid Iodine solutions - PLUS splatter one’s plate with triple amounts of Kelp granules. Choose wisely and ask God for wisdom and He might tell you -- “moderation in all things”.

* This article is not for any purpose other than for information. It is strongly advised that consultation with a trusted licensed health practitioner be undertaken before consuming any Iodine supplements.  You may not need Iodine at all but symptoms many times are confused with those of Adrenal Fatigue or low adrenal condition.  The endocrine system is complex and very sensitive and unfortunately, not too many doctors are versed in all the complexities.  Choose Wisely.



(1) McClure RD. Goiter prophylaxis with iodized salt. Science. 1935 Oct 18;82(2129):370–1

(2) Institute for Traditional Medicine,

(3) Asian Food Info,

(4) Livestrong,

*Photos courtesy of, and Kikkoman.Eur

Written by Beverly Anne Sanchez, October 8, 2011


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