Iodine Bioavailability and Accumulation of Arsenic and Cadmium in Rats Fed Sugar Kelp (Saccharina latissima)

Simultaneous speciation analysis of arsenic and iodine in human urine by high performance liquid chromatography-inductively coupled plasma mass spectrometry

A high-performance liquid chromatography-inductively coupled plasma mass spectrometry-based method was developed for the simultaneous determination of four iodine species (i.e. iodate, 3-iodo-tyrosine, 3,5-diiodo-tyrosine, and iodide) and six arsenic species (i.e. arsenobetaine, arsenite, dimethylarsinic acid, arsenocholine, methylarsonic acid, and arsenate) in human urine. The chromatographic separation was performed on a Dionex IonPac As7 anion exchange column. The mobile phase was initiated with 0.5 mmol/L ammonium carbonate solution, followed by 50 mmol/L ammonium carbonate/100 mmol/L ammonium nitrate solution (with 4% methanol). The limits of quantification of the analytes ranged from 0.045 to 2.26 μg/L. At three spiked levels (10.0, 20.0, 50.0 μg/L), the average recoveries (%) ranged from 87.4 to 113.1%, and the relative standard deviations (RSD, %) ranged from 0.4 to 17.2%. The ratio of the sum of six arsenic species to the total arsenic measured by ICPMS ranged from 77.4 to 121.2%, and the ratio of the sum of the four iodine species to the total iodine ranged from 70.7 to 114.7%, indicating a good agreement between these two methods for both arsenic and iodine.

Bioavailability of iodine from a meal consisting of sushi and a wakame seaweed salad-A randomized crossover trial

The consumption of seaweed is on the rise in the Western world. Seaweeds may contain substantial amounts of iodine, and some species could serve as a potential dietary iodine source. However, limited data on the iodine content and in vivo bioavailability of iodine from seaweeds exist. The objective was to assess whether iodine from a meal consisting of sushi with nori, (Porphyra spp) and a wakame seaweed salad (Undaria pinnatifida) had similar bioavailability as a potassium iodide reference supplement of similar iodine content. A randomized 2 × 2 crossover trial (AB/BA model) was conducted in 20 healthy young women. One intervention arm consisted of a meal with sushi and wakame salad (231 μg iodine), and the other of potassium iodide (KI) supplement (225 μg iodine). Urinary iodine concentration (UIC) was measured at 11 different time points for 48 h after the interventions. The UIC increased after consumption of both the sushi and wakame meal and the KI supplement, but the median UIC was higher after ingestion of the KI supplement. The estimated bioavailability of iodine during the first 24 h was 75% from sushi with wakame and 97% from the KI supplement. The bioequivalence analyses confirmed that the KI supplement had higher estimated bioavailability than the sushi and wakame meal, however, with small margins. Our findings on iodine bioavailability imply that sushi and wakame could be potential iodine sources in the diet, which may be favorable for population groups at risk for iodine deficiency. However, further research is needed to account for the variability of iodine content in seaweeds by different locations and degree of processing, to assure that the iodine levels are stable and predictable for the consumers.