Evaluation of Iodine Bioavailability in Seaweed Using in Vitro Methods

Area of Science:

• Nutritional Science
• Food Chemistry

Background:

• Seaweed consumption can lead to excessive iodine intake due to high iodine content.
• Iodine bioavailability from food sources, particularly seaweed, is not well-established.
• Post-ingestion processes significantly affect the amount of iodine reaching systemic circulation.

Purpose of the Study:

• To estimate the in vitro bioavailability of iodine from various commercial seaweeds.
• To compare different in vitro methodologies for assessing iodine bioavailability.
• To determine the bioaccessibility and potential systemic absorption of iodine from seaweed.

Main Methods:

• In vitro digestion models simulating gastrointestinal processes.
• Solubility, dialyzability, and intestinal cell transport/uptake assays.
• Analysis of iodine content and absorption across different seaweed types, including kombu.

Main Results:

• Iodine bioaccessibility after in vitro digestion ranged from 49-82%, with kombu showing the highest values.
• Dialysis and cell culture methods yielded lower estimates for systemic iodine bioavailability (5-28% and ≤3%, respectively).
• Methodologies significantly influence the estimated amount of absorbable iodine from seaweed.

Conclusions:

• Iodine in seaweed is generally bioaccessible after digestion, but actual bioavailability for systemic circulation may be considerably lower.
• The choice of in vitro methodology critically impacts the assessment of iodine bioavailability from seaweed.
• Further research is needed to refine methods for accurate iodine bioavailability determination in seaweed.