Effects of kelp supplementation on thyroid function in euthyroid subjects

The increasing popularity of seaweed baths showed modest uptake of iodine probably through a mixture of skin absorption and respiration following such treatments 51. The finding that iodine status was not significantly enhanced by coastal living alone was supported by findings in Portugal 52 of lower UI values in the Azores and Madeira islands compared to the Portuguese mainland. Lower UI values were reported on the island of Zakynthos and higher values on Chios than on mainland Greece 53, 54. Chios in the Aegean is seaweed rich, while Zakynthos in the Ionian Sea has relatively little seaweed 53. Similarly, low UI was reported from Hong Kong 55, a coastal area where adequate iodine intake might have been anticipated.

The People’s Pharmacy Bottom Line:

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider. On further questioning, the patient complains of a general history of fatigue, weight gain, constipation, dry skin, muscle aches synthroid migraine and low mood.

Table 3. Iodine concentration of EN formula (on the market in Japan).

Failure to achieve a satisfactory weight loss may induce the hypothyroid participants to persist or even increase the consumption of the iodine-rich diet with the following worsening of the negative metabolic effects.
This interaction could result in very serious and potentially life-threatening consequences.
Despite its benefits for increasing iodine intake, iodized salt does not provide a panacea for solving iodine deficiency.
The thyroid gland concentrates iodide from the bloodstream by a factor of about 40 28.
Incorporating seaweed into one’s diet can provide a natural source of iodine, potentially supporting thyroid health.

In our case, a participant with no evidence of pre-existing or underlying thyroid disease assumed for 10 days a daily dose of about 1800 μg iodine. In the acute hyperthyroid phase, the increased blood flow observed diffusely throughout the gland by colour Doppler ultrasonography, supports the occurrence of the Jod-Basedow phenomenon. The following hypothyroidism occurred about 2 months after diet discontinuation, was accompanied by inhibition of iodine uptake and normal urinary iodine secretion, suggesting a persistent downregulation of NIS.

The inconsistency of iodine content in kelp supplements makes them a poor and difficult-to-control iodine supplement. According to MedlinePlus, there is not enough hard evidence to determine that taking kelp actually improves iodine levels, let alone helps thyroid disorders. Sources of dietary iodine, its assessment, recommended dietary intake, and consequences of iodine excess are outlined. The benefits and possible dangers of dietary intake of iodine-rich seaweed are described.

Supplementation with sea kelp

One month later, the patient complained of cold intolerance, dry skin, sleepiness, weakness and depression.
The objective of this communication is to review the association with thyroid function of seaweed-derived iodine intake, outlining the beneficial and in some case adverse consequences of this association.
Iodine is an essential trace mineral; the body can’t produce it, so it has to come from your diet.
Thus, maternal iodine intake is necessary for both mother and baby to thrive, and even mild iodine deficiency can lead to lower cognitive development 3.
In addition to iodine released from seaweeds, it appears that iodine deposition as rain has increased in recent times.

In our case, the patient discontinued taking the kelp containing tablets and was treated with Methimazole for 3 months. She regained normal thyroid function and maintained it for 1 year following treatment, thus completely reversing the hyperthyroidism. Most individuals can tolerate chronic excess iodine without clinical symptoms, the normal thyroid gland can adapt to excess iodine by the mechanisms described above. Sometimes these mechanisms fail, and excess iodine leads to overt clinical hyperthyroidism or hypothyroidism. In some instances, such as in a multinodular goiter, the excess iodine can trigger hyperproduction of thyroid hormones leading to clinical signs of hyperthyroidism.

Seaweed’s nutritional benefits

One source of iodine is seaweed which as a foodstuff is enjoying an increasing profile in Western countries. Apart from its potential involvement in thyroidal health, gaseous iodine released from seaweeds plays a significant role in influencing coastal climate through cloud formation. Treatment of hyperthyroidism requires ending the excess iodine exposure and use of an antithyroid medication. Generally, after a few months of treatment, the normal thyroid function is recovered.

Just as too much iodine can block the proper production of hormones in the thyroid gland, a deficiency of iodine can make the thyroid work harder. But iodine is a trace mineral, meaning that your body only needs a tiny amount of it in order to be healthy. And as the ‌Journal of the European Economic Association‌ explained in 2017, the serious effects of iodine deficiency became greatly reduced in the United States once iodine started being added to table salt nationwide in 1924. Today, iodine deficiency is rare in the United States, says the Cleveland Clinic. Twenty days later, signs of hyperthyroidism and biochemical hyperthyroidism were more evident.

Under iodine replete conditions, this requirement can usually be met from normal foodstuffs, particularly if salt is iodized.
The inconsistency of iodine content in kelp supplements makes them a poor and difficult-to-control iodine supplement.
Heavy metal concentrations in seaweeds are generally below levels that are toxic for humans.
It’s important to recognize that the high doses of iodine in kelp supplements and other dietary sources can throw your thyroid out of whack even if you don’t currently have thyroid issues.
Even a minor iodine deficiency can result in adverse thyroidal health consequences while excess iodine intake can also result in thyroid function disorders.
Use of iodized salt with or without appropriate supplements to achieve adult or pregnancy daily (150 or 250 μg) intakes in vegans and non-vegans alike is recommended 37, 38, 39.

Transient Hyperthyroidism following the ingestion of complementary medications containing kelp seaweed

A fewdomestic reports describing ID in subjects on long term total EN (TEN) have been published since early 1990s(6, 7). In this report, we presentseven patients who developed hypothyroidism due to iodine deficiency (HID) during long-term TEN. Some types of seaweed have a high concentration of arsenic and other heavy metals like lead, mercury, and aluminum. Iodine and mercury can have a synergistic effect—affecting thyroid function and reducing the thyroid hormone T3.

Even short-term supplementation with kelp or seaweed — especially at levels of more than 150 micrograms of iodine per day — can cause temporary hyperthyroidism and thyrotoxicosis—excess levels of thyroid hormones in the bloodstream (32-35). Although sea kelp supplements are widely available, the adverse effects on thyroid function are not clearly publicised on the packaging. It is a common patient misconception that herbal products are safe because they are ‘natural’ and lack any side effects; therefore, it is vital to ask patients about their consumption of prescribed medications, over-the-counter products and herbal remedies.

The most common primary cause of hypothyroidism is Hashimoto’s disease, an autoimmune condition, in which the body’s own immune system attacks the thyroid gland, resulting in damage and an impaired capacity to make and release enough thyroid hormones1. Other primary causes of hypothyroidism include treatment of hyperthyroidism, iodine deficiency, thyroiditis, and certain medicines that can have an impact on thyroid function, such as lithium and amiodarone2. These values were extracted from publications cited in this review 35, 37, 39 and are intended to give an indication of possible iodine intake arising from consumption of these seaweeds. Adults who consume complementary medication based on kelp seaweed should be informed of the risk of developing thyroid dysfunction also in the absence of any pre-existing thyroid disease.