Nutr Res Pract.  2024 Jun;18(3):412-424. 10.4162/nrp.2024.18.3.412.

Iodine intake from brown seaweed and the related nutritional risk assessment in Koreans

• Kwon SO
• Kwon KI
• Lee MY
• Lee HY
• Kim Ci

• KMID: 2558513
• DOI: http://doi.org/10.4162/nrp.2024.18.3.412

Abstract

BACKGROUND/OBJECTIVES
Although iodine is essential for thyroid hormone production and controls many metabolic processes, there are few reports on the iodine intake of the population because of the scarcity of information on the iodine content in food. This study estimated the iodine intake of Koreans from brown seaweed, the major source of iodine in nature.
SUBJECTS/METHODS
The dietary intake data from the recent Korea National Health and Nutrition Examination Survey (2016–2021) and the iodine content in brown seaweed were used for the estimation. Nationwide brown seaweed samples were collected and prepared using the representative preparation/cooking methods in the Koreans’ diet before iodine analysis by alkaline digestion followed by inductively coupled plasma mass spectrometry.
RESULTS
The mean (± SE) iodine intake from sea mustard was 96.01 ± 2.36 µg/day in the Korean population. Although the iodine content in kelp was approximately seven times higher than that in sea mustard, the mean iodine intake from kelp (except broth) was similar to that of sea mustard, 115.58 ± 7.71 µg/day, whereas that from kelp broth was 347.57 ± 10.03 µg/day. The overall mean iodine intake from brown seaweed was 559.16 ± 13.15 µg/day, well over the Recommended Nutrient Intake of iodine for Koreans. Nevertheless, the median intake was zero because only 37.6% of the population consumed brown seaweed on the survey date, suggesting that Koreans do not consume brown seaweed daily.
CONCLUSION
The distribution of the usual intake of iodine from brown seaweed in Koreans would be much tighter, resulting in a lower proportion of people exceeding the tolerable upper intake levels and possibly a lower mean intake than this study presented. Further study evaluating the iodine nutriture of Koreans based on the usual intake is warranted. Nevertheless, this study adds to the few reports on the iodine nutriture of Koreans.

Keyword

Iodine intake; brown seaweed; nutritional risk; usual intake

Figure

• 

  Fig. 1 Iodine content in sea mustard (µg/100 g dry weight) according to the city and preparation method.The iodine content in the prepared samples was converted to the corresponding value in dried sea mustard.As is, dried sea mustard; soaked, dried sea mustard soaked in water for 60 min and drained; boiled, soaked, and drained sea mustard boiled for 15 min as explained in the Supplementary Table 1.

• 

  Fig. 2 Iodine content in kelp (µg/100 g dry weight) according to the city and preparation method.The iodine content in the prepared samples was converted to the corresponding value in dried kelp.As is, dried kelp; soaked, dried kelp soaked in water for 60 min and drained; boiled, dried kelp boiled for 15 min; Broth, kelp broth; Broth, as is, Iodine content in kelp broth (liquid) prepared, cooled and boiled again for 15 min as explained in the Supplementary Table 1.

• 

  Fig. 3 Mean and 95th percentile intake of iodine according to the age group in the Korean population with the corresponding ULs. All analyses accounted for the complex sampling design effect and appropriate sampling weights.DRI, Dietary Reference Intake; UL, tolerable upper intake level.

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