kelp

Also indexed as
Ascophyllum nodosum, Laminaria digitata
Introduction
Kelp is a sea vegetable that is a concentrated source of minerals, including iodine, potassium, magnesium, calcium, and iron. Kelp as a source of iodine assists in making thyroid hormones, which are necessary for maintaining normal metabolism in all cells of the body.
Where is it found?
Kelp can be one of several brown-colored seaweed species called Laminaria.
Kelp has been used in connection with the following condition (refer to the individual health concern for complete information):
Science Ratings - Health Concerns
* - Iodine deficiency
*** - Reliable and relatively consistent scientific data showing a substantial health benefit.
** - Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
* - For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.
Who is likely to be deficient?
People who avoid
sea vegetables, as well as dairy, seafood, processed food, and the salt shaker, can become deficient in iodine. Iodine deficiency can cause low thyroid function, goiter, and cretinism. Although iodine deficiency is now uncommon in Western societies, the U.S. population has shown a trend of significantly decreasing iodine intake.
How much is usually taken?
Since the introduction of iodized salt, additional sources of
iodine, such as kelp, are not necessary for most people. However, kelp can be consumed as a source of other minerals. A report from Great Britain indicated that the average kelp-based supplement contained 1,000 mcg of iodine (the adult RDA in the United States is 150 mcg per day). It has been suggested that intakes above 2,000 mcg per day should be regarded as excessive or potentially harmful.1
Are there any side effects or interactions?
There have been several case reports of high intakes of kelp providing too much
iodine and interfering with normal thyroid function.2 3 4 5 6 People with thyroid disease should check with a doctor before taking supplements that contain kelp.
At the time of writing, there were no well-known drug interactions with kelp.