Tuesday, May 23, 2017

Iodine Fortification

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

Iodine Fortification

Benmiloud, M., Bachtarzi, H. & Chaouki, M.B. 1983. Public health and nutritional aspects of endemic goitre and cretinism in Africa. In: Delange F., Ahluwalia R. (eds) Cassava toxicity and thyroid. p. 50. Research and Public Health Issues, IDRC, Ottawa.
Iodine deficiency is present in almost all parts of the developed and developing world, and environmental iodine deficiency is the main cause of iodine deficiency disorders. Iodine is irregularly distributed over the earth’s crust, resulting in acute deficiencies in areas such as mountainous regions and flood plains. The problem is aggravated by accelerated deforestation and soil erosion. 
Thus, the food grown in iodine-deficient regions can never provide enough iodine for the people and livestock living there. The iodine deficiency results from geologic rather than social and economic conditions. It cannot be eliminated by changing dietary habits or by eating specific kinds of foods but must be corrected by supplying iodine from externalsources. 
It has, therefore, been a common practice to use common salt as a vehicle for iodine fortification for the past 75 years. Salt is consumed at approximately the same level throughout the year by the entire population of a region. Universal salt iodisation is now a widely accepted strategy for preventing and correcting iodine deficiency disorders.
There are areas where consumption of goitrogens in the staple diet (e.g., cassava) affects the proper utilisation of iodine by the thyroid gland. For example, in Congo, Africa, as a result of cassava diets there is an overload of thiocyanate.
World Health Organization. 1994. Iodine and health: A statement by WHO. WHO/NUT/94.4. 
To overcome this problem, appropriate increases in salt iodisation are required to ensure the recommended dietary intake. The iodisation of salt is done either by spraying potassium iodate or potassium iodide in amounts that ensure a minimum of 150 μg iodine/day. Both of these forms of iodine are absorbed as iodide ions and are completely bio-available. Other methods of iodine prophylaxis are also used: iodised oil (capsule and injections), iodised water, iodised bread, iodised soya sauce, iodoform compounds used in dairy and poultry, and certain food additives.
ICCIDD/MI/UNICEF/WHO. 1995. Salt iodisation for the elimination of iodine deficiency.
Iodine loss occurs as a result of improper packaging, Humidity and moisture, and transport in open trucks and railway wagons exposed to sunlight. To compensate for these losses, higher levels of iodine are used during the production of iodised salt. Losses during the cooking process vary from 20 percent to 40 percent depending on the type of cooking used.
WHO/UNICEF/ICCIDD. 1992. Indicators for assessing Iodine Deficiency Disorders and their control through salt iodisation. Report of a Joint Consultation, World Health Organization, Geneva. November 1992: Document WHO/NUT/94.6.
To ensure the consumption of recommended levels of iodine, the iodine content of salt at the production level should be monitored with proper quality assurance programmes. Regular evaluation of the urinary iodine excretion pattern in the population consuming iodised salt or exposed to other iodine prophylactic measures would help the adjusting of iodine intake.

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