MENU
News

Caution with Kelp Supplements: May Contain Too Much Iodine

White Plains, New York, April 25, 2017 — Kelp supplements are promoted as a natural source of iodine, an important mineral for healthy thyroid function. But are they a good alternative to regular iodine supplements? To find out, ConsumerLab.com recently selected six popular kelp supplements sold in the U.S. and Canada and tested their quality. ConsumerLab found that half contained approximately twice the amount of iodine listed on their labels, and one of these products was also contaminated with arsenic, a toxic heavy metal.

High doses of iodine can cause thyroid dysfunction and have other negative effects. To be safe, the FDA states that a kelp supplement should not provide more than 225 mcg of iodine per daily serving. ConsumerLab found 530 mcg to 960 mcg per daily serving in the three products which failed its testing.

"While a quality kelp supplement can be a good, natural source of iodine, our tests show that consumers must choose very carefully to ensure they are not getting more iodine than expected, or unnecessary exposure to arsenic" said ConsumerLab.com President Tod Cooperman, M.D.

Most people get enough iodine through their diet, from dairy foods, bread, seafood and iodized salt. However, people who maintain a low-salt diet (or who regularly use specialty salts, which typically are not iodized), or who have other dietary restrictions, may be at risk for deficiency. Woman who are pregnant or nursing who need iodine are advised to supplement with potassium iodide, the form of iodine commonly found in other iodine supplements as well as many multivitamins. Clinical research suggests that iodine from kelp may be absorbed only half as well as that from a potassium iodide supplement.

ConsumerLab.com's findings are now available online in its Kelp Supplements Review (https://www.consumerlab.com/reviews/Kelp_Supplements_Review/Kelp/). Included in the report is information to help consumers understand the pros and cons of using kelp supplements, dosage, and the potential side-effects and drug interactions of kelp supplements.

Products in the report include the six selected by ConsumerLab, two others tested through its voluntary Quality Certification Program, and one product which is similar to another which passed testing. The products are: Natural Factors Liquid Kelp, Nature's Answer Kelp Thallus, Nature's Life Icelandic Kelp, Progressive Laboratories Kelp, Puritan's Pride Premium Sea Kelp, Solgar North Atlantic Kelp, Swanson Kelp, Traditional Foods Market Kelp Powder and Vitamin World Sea Kelp.

Founded in 1999, ConsumerLab.com is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. Membership to ConsumerLab.com is available online and provides immediate access to reviews of more than 1,000 products from over 400 brands. The company is privately held and based in Westchester, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products.