The conventional wisdom is that all the seaweeds in the Salish Sea are edible with the exception of Desmarestia spp which is commonly refered to as ‘Witch’s Hair.’ Among the 200 other species found here iodine concentrations can vary from 16µg/g in Porphyra spp (or Nori) to over 8000µg/g in Laminaria digitata (marketed as ‘kelp granules’). The FDA has set the acceptable daily intake of iodine for adults from a minimum of 150µg/day to a maximum of 1100 µg/day (200µg/day for toddlers).
However, these plants are also one of the best sources of trace minerals, including iodine, available. Blanching, sun drying and other techniques lower the iodine values and some contain T4 precursors that can greatly benefit those with thyroid problems. Dr Ryan Drum is a local treasure in the San Juan Islands and we highly recommend those with questions about thyroid function and purchasing edible Salish Seaweeds to his website.