Goitres are one of the most visible signs of iodine deficiency disorders
Goitres are one of the most visible signs of iodine deficiency disorders
A recent breakthrough in food-fortification technology that allows two essential elements — iodine and iron — to be added to table salt represents a major advance in international efforts to prevent health problems associated with micronutrient deficiencies.
For more than 20 years, scientists have tried without success to fortify salt with iodine and iron in such a way that the two micronutrients do not react and lose their potency. When iron and iodine interact, the amounts available for absorption by the human body is significantly reduced, explains Levente Diosady, a Professor of Food Engineering at the University of Toronto.
This breakthrough involves covering iodine particles with a capsule made from dextrin, a water-soluble starch compound, which serves as a physical barrier between the two elements. The double-fortification technology was developed with support from the Micronutrient Initiative (MI) and IDRC. The MI is an international secretariat based at IDRC that aims to eliminate health problems resulting from deficiencies in iron, iodine, and vitamin A.
Iodine-fortified salt was introduced in North America and parts of Europe during the 1920s as a means of combating iodine deficiency disorders in the population. Iodine is an essential component of thyroid hormone, a substance that contributes to brain development in the fetus and regulates human metabolism. Iodine deficiency is the single greatest cause of preventable mental retardation in the world. Other related disorders include lethargy, physical disabilities, goitre, still-births, and neonatal deaths.
In theory, the combination of iodine and iron in salt can simultaneously combat iodine and iron deficiency disorders, which together affect more than one-third of the world's population. Iron deficiency is the most common nutritional problem in the world, particularly among women, infants, and children. Health problems associated with a lack of iron in the diet include anemia, fatigue, learning problems, pregnancy complications, premature births, and maternal mortality.
Iodine is naturally present in water and soil, although some soils contain very low amounts. As a result, seafood is a more reliable source of iodine than crop plants. Around 1.6 billion people in more than 100 countries live in areas where iodine is not available in sufficient quantities. Those most at risk include approximately one-third of the population of China. Iodine deficiency is also a severe problem in the Himalayas, the Andes, India, and West Africa.
Researchers at the Hospital for Sick Children in Toronto are testing the efficiency of absorption of iodine and iron in double-fortified salt into the human body. Later this year, the new salt will undergo further tests by University of Ghana scientists. The IDRC-funded trials will target women and their families in areas of Ghana where iron- and iodine-deficiencies are endemic.
Michael Boulet is a research analyst at IDRC.
Resource Persons:
Dr Levente Diosady, Professor of Food Engineering, University of Toronto, Toronto, Ontario, Canada; Tel: (416) 978-4137; Fax: (416) 978-8605
Dr Janice L. Johnston, Program Officer, Programs Branch, IDRC, PO Box 8500, Ottawa, Ontario, K1G 3H9, Canada; Tel: (613) 236-6163; Fax: (613) 567-7748; E-mail: jjohnston@idrc.ca
Dr Venkatesh Mannar, Executive Director, The Micronutrients Initiative, c/o International Development Research Centre, PO Box 8500, Ottawa, Ontario, K1G 3H9, Canada; Tel: (613) 236-6163 ext. 2118; Fax: (613) 567-4349; E-mail:mi@idrc.ca