Eaten as a food, kelp contains low enough arsenic levels to be safe for human consumption; but some kelp supplements have potentially toxic concentrations of arsenic. … All but one contained levels of arsenic higher than the Food and Drug Administration tolerance level of 0.5 to 2 parts per million.

Does seaweed contain arsenic?

Commonly consumed seaweeds are known to contain high levels of arsenic, primarily in organic forms1. … The presence of arsenic in seaweed products, and its ability to form potentially toxic species has raised concern about possible human health impacts of seaweed consumption.

Is kelp harmful to humans?

Side effects, toxicity, and interactions Kelp may contain harmful metals. These include cadmium, lead, aluminum, and other heavy metals. This is more likely if you eat a lot of kelp from areas of contaminated ocean water. Women who are pregnant or breastfeeding shouldn’t use kelp supplements.