For years my sister has extolled to me the virtues of kelp supplements. Often cited by the manufacturers as helpful in controlling thyroid and for reversing mineral deficiencies, these supplements are made from algae and purport to convey important minerals from the sea.

A new study, however, casts a shadow over the health claims as public health expert Marc Schenker reports having found arsenic in 8 out of 9 over-the-counter kelp products. Seven had a level exceeding the tolerance levels set by the FDA (hard to believe there’s a tolerance level of arsenic in food products, isn’t it?).

This isn’t a case of tampering or an industrial accident that caused arsenic to somehow get mixed in with the kelp in manufacturing. Arsenic is a heavy metal that is often a by-product of industrial and agricultural activities. Kelp that is harvested close to shore may have absorbed heavy metals and toxins.

Apparently arsenic shows up in some food, especially seafood. The problem with herbal supplements though, is that the FDA has only limited control over herbal supplements.

For anyone taking kelp as a daily supplement, this is important news. But what is equally important is that levels of arsenic that are higher than those found in the kelp supplements may be found in other homeopathic remedies and implicated in arsenic poisoning of consumers who ingested them.