IODINE IN FOODS-NEED FOR MONITORING

Iodine deficiency amongst some populations has been a long standing problem and universal iodization of salt was thought of as a solution to tackle the same. Deficiency syndromes are mostly observed amongst people living in land locked areas with low access to sea foods. According to some estimates there are about 2 billion people in the world experiencing iodine deficiency to varying extent . The daily need for iodine is placed at 150-290 ug for different categories of people including pregnant women. In India alone there is reported to be 100 million people suffering from iodine deficiency and Goiter, the resultant disease. In human body iodine is located in Thyroid tissues and hormones (about 30%) while the remaining portion is distributed amongst mammalian glands, eyes, gastric mucosa, the cervix, and salivary glands. Serious deficiency can even lead to cancer and other fatal diseases. But iodine toxicity is rarely known and therefore the recent episode in Australia where consumers taking one particular brand of soy drink were affected by Thyrotoxicosis, was shocking to safety authorities there.

"There is a "strong public health argument" to monitor the iodine levels of certain risky foods imported into Australia following the Bonsoy incident, experts say. The popular soy drink was pulled from store shelves nationwide late last year after it was found to contain excessive levels of the mineral, and scores of people suffered thyroid-related illness.Bonsoy was found to contain about one thousand times the iodine of rival soy brands, meaning an adult could exceed their daily safe dosage in a few spoonfuls. Endocrinologist Dr Bronwyn Crawford is co-author of a paper, published in the latest Medical Journal of Australia, which details the cases of eight people who suffered Bonsoy-related illnesses. One was a 38-year-old man who "drank Bonsoy in take-away coffee". He developed thyrotoxicosis, a life-threatening condition involving an overactive thyroid which can cause heart palpitations and attack. "After he ceased drinking all soy milk his symptoms abated and his serum thyroid-stimulating hormone level normalised three months later," Dr Crawford, from the University of Sydney, said. A further case was that of a newborn baby whose mother had been drinking Bonsoy daily and "breastfeeding since delivery". "... Between January and June 2010, 48 retrospective Australian cases of thyroid dysfunction associated with this brand of soy milk were also notified to local public health authorities," Dr Crawford said. The paper also noted a "cluster of cases of thyrotoxicosis" linked to an "unidentified soy milk" reported in New Zealand in 2005. The excessive iodine was traced to a type of seaweed used in the manufacture of Bonsoy, and samples of the soy drink revealed iodine concentrations from 25,000 to 27,000 micrograms per litre. This was compared to the iodine levels of rival soy drinks, of just 15 to 28 micrograms per litre".

Naturally this episode has raised concerns about the danger posed by products containing seaweeds which can concentrate iodine from seawater and with coastal waters often being polluted by dumping of wastes there is no way iodine build up can be avoided. Normally if people have access to foods like wheat, maize, milk, legumes etc adequate iodine intake can be assured. Sweet potato contains iodine as high as 300 ug per 100 gm while maize has 100 ug, soybean 179 ug, peanut 94 ug, bread 300 ug and milk 88 ug/250 ml. Regular diets containing some of these components can ensure iodine intake much beyond the minimum level desired. To doubly make sure that iodine deficiency does not occur, many countries have consciously adopted salt iodization programs where table salt is blended with small amounts of an iodine compound like sodium iodide, potassium iodide or potassium iodate. After the compulsory iodization of salt in India some years ago the incidence of Goiter is reported to be declining dramatically, the cost being hardly a few paise per beneficiary.

V.H.POTTY
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