Iodine source apportionment in the Malawian diet

Area of Science:

• Nutritional science
• Public health
• Food science

Background:

• Iodine (I) deficiency is a global public health concern.
• Assessing iodine status is crucial for preventing iodine deficiency disorders.
• Malawi's diverse agricultural and water sources necessitate a detailed nutritional assessment.

Purpose of the Study:

• To characterize iodine nutritional status in Malawi.
• To assess dietary iodine intake from various food sources and water.
• To evaluate the impact of soil type on iodine status.

Main Methods:

• Dietary iodine intake was assessed using crop, fish, salt, and water iodine concentrations.
• Urinary iodine concentration (UIC) was measured in 60 women on calcareous and non-calcareous soils.
• Data were analyzed to determine median iodine concentrations and intake levels.

Main Results:

• Staple foods (maize, roots, tubers) had low iodine concentrations.
• Leafy vegetables and freshwater fish were richer sources of iodine.
• Mean dietary iodine intake from food (excluding salt) was significantly below the adult requirement.
• Despite low food-based intake, median UIC indicated adequate to excessive iodine levels, suggesting iodized salt as the primary source.
• Drinking water contributed significantly to iodine intake in some regions.

Conclusions:

• Iodized salt is the principal determinant of iodine nutrition in Malawi.
• Monitoring and ensuring the quality of iodized salt are critical for public health.
• Drinking water can be a notable iodine source in specific Malawian areas.