Did you know that mineral content of seaweeds (K, Ca, Na, P, Cu, Fe, Se, Mn, Zn, Mg, Cr, and I) is at least 10 times higher than of earthy plants, reaching 20-50% of their dry weight?
However, if eaten too much and too often, seaweeds can be harmful for your health. They have a high absorption capacity and accumulate toxic metals, such as mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), and aluminium (Al). The concentration of toxic metals highly depends on the country of origin. For example, asian seaweeds show the highest cadmium, lead and alumium concentrations. European seaweeds have the highest mercury content.
So how much seaweed you need to eat to benefit from its high mineral content and not risk your health? Consumption of 5 g/day of dehydrated seaweed is considered to be safe for adults.