Exposure to iodine, essential and non-essential trace element through seaweed consumption in humans

Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace elements highlight the need for comprehensive studies on exposure associated with seaweed consumption. To address this gap in knowledge, we carried out a feeding intervention study of three common edible seaweeds (Nori, Kombu, and Wakame) in 11 volunteers, aiming to elucidate the extent of both beneficial and harmful trace element exposure through seaweed consumption in humans. Concentrations of total arsenic, cobalt, copper, cadmium, iodine, molybdenum, selenium, and zinc were measured in urine samples before and following seaweed consumption. Elements concentrations were also measured in the seaweeds provided for the study. Descriptive analysis for each element were conducted and we used quantile g-computation approach to assess the association between the 8-element mixture and seaweed consumption. Differences in urine element concentrations and seaweed consumption were analyzed using generalized estimating equations (GEE). Urinary concentrations of iodine and total arsenic increased after seaweed consumption. When we analyze the 8-element mixture, the largest weight was observed for iodine after Kombu consumption while for total arsenic was observed after Wakame consumption. Similar results were observed when we compared the mean differences between the elements before and after seaweed consumption through the GEE. Seaweed consumption relates with increased urinary iodine and total arsenic concentrations, particularly after Kombu and Wakame consumption.