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It is hard to accept that iodine deficiency, the most common preventable cause of
mental deficiency in the world today9, is still prevalent in Europe. The
main cause of this situation is the lack of awareness and consequently of appropriate
action by health authorities, including the medical doctors, and the public at
large. The strategy for the elimination of iodine deficiency in Europe must start with information and health education through appropriate channels, not only of the public, but also of the health professionals . Consumption of seafood, the main dietary source of iodine, must be encouraged, but is of limited value. The major measure for the prevention of IDD in Europe clearly is through Universal Salt Iodization (USI), i.e. the fortification of all salt for human and animal consumption and for the food industry9,10,29. Possible side effects of iodine supplementation delivered by salt should be openly addressed, but without causing undue concern47,48. Also, programs should clearly avoid the impression that they do advocate a higher salt intake. In 1992, iodized salt was available in most European countries, usually nation-wide, with the exception of Denmark where it was prohibited up to 199919. It was compulsory in 8 countries, including Austria, and voluntary in all the others, including Switzerland. The price was most usually barely higher than non iodized salt; it was even lower in France. From 1992 onwards, and especially following the endorsement by WHO Euro of the recommendations resulting from the Brussels meeting11 to appoint national iodine committees in all countries and to promote the use of iodized salt, quite significant progress has been achieved in many European countries (see Table 6). National programs have been organized, which could result, as for example in Poland49, in an exhaustive re-evaluation of the situation and in practical measures aiming at the implementation of USI. The level of iodization of salt must be adapted at regular intervals to compensate for changing salt intake. For example, in Switzerland, because of the progressive decline in salt intake, the iodine intake slightly decreased in the seventies. In 1980, the level of salt iodization was therefore increased from 7. 5 to 15 ppm. This resulted in an increase of iodine intake from a borderline value of 90 µg/day to a perfectly adequate value of 150 µg/day. Rather unexpectedly, this change was not accompanied by any significant increase in the incidence of iodine-induced hyperthyroidism but rather, by a steady decline in the incidence of both toxic nodular goiter and Graves' disease50. European countries which are actually in a state of moderate iodine deficiency thus may expect to make the transition to iodine sufficiency not only with no ill effects, but with the unexpected large benefit of a marked decrease of the incidence of hyperthyroidism in the elderly in addition to the disappearance of euthyroid goiter15,37–39. In their report published in 199914, WHO/UNICEF/ICCIDD indicated that iodized salt was then available in all 18 iodine deficient countries in Europe and that legislations on iodized salt were available in 12 of them. Table 6 summarizes the latest information available on the use and legal status of iodized salt in Western and Central European countries. Most countries have created a legal basis or even established a monitoring and/or promotional program. Iodized salt is now compulsory in 12 countries. It is voluntary in 17, and the status of enforcement is unknown in the last 2 countries, Albania and Iceland. 15 countries require iodide, 6 require iodate, and 9 countries allow both iodide and iodate. The level of salt iodization for household salt ranges from 5 to 70 ppm. The figures for the market share of iodized packed salt sold to the households vary from 1 % in Portugal to at least 90 % in Austria, Bulgaria, Croatia, the Czech Republic, Finland, Macedonia and Poland. These figures must be considered with great caution, since salt producers unwillingly divulge sales figures, and regular household surveys are tedious to perform. Even when iodized salt is enforced by law, its market share may remain low, because of lack of political will, non-compliance of retailers, distribution of cottagesalt or low price imports. Market shares for the salt for food industry are even more difficult to estimate. The staggering diversity of legal arrangements shown in Table 6 results from several factors:
As long as USI is not systematically implemented in Europe, special attention has to be devoted to the protection of the two main target groups to the effects of iodine deficiency, i.e. pregnant and nursing women, neonates and young infants. If iodine deficient, these age groups should be supplemented with physiological quantities of iodine, for example by including iodine to the multivitamins prepared for them. Moreover, the iodine content of formula milk should be increased in Europe above the classical recommendation of 5 µg/dl. The present recommendations, endorsed by WHO Euro and by ICCIDD, are 10 µg/dl milk for fullterms and 20 µg/dl for preterms11. In some European areas affected in the past by overt endemic cretinism, iodine deficiency was and remains severe, for example in parts of Turkey52 and Romania (unpublished), with impairment of neonatal thyroid function and, consequently, with potentially harmful consequences for brain development. In such situations, emergency and transient more drastic measures can be justified from a public health point of view, such as the oral administration of iodized oil. It is now demonstrated that in many industrialized countries such as the United States, Great Britain and Northern European countries, the main source of dietary iodine is neither iodized salt nor seafoods but dairy milk27. This results either from the use of iodophors in the industrial processing of milk or from iodine supplemented diets for the animals, or from both. European rules for monitoring the iodine content of milk and a precise evaluation of the possible role of milk as a substrate for iodine supplementation in Europe are desirable. Iodinated water has proved to be efficient in the control of iodine deficiency in developing countries in situations where iodized salt is hard to implement, where the access to water is well localized, for example by wells, and where most of the water is used for human and animal consumption (Review in ref. 53). These conditions are probably rarely met in European countries. Finally, it is conceivable that in exceptional circumstances where iodide or iodate are not accepted as sources of iodine for salt iodization for personal reasons, the use of natural seaweeds as a source of iodine could be considered54.
Table 6. Regulations governing iodised salt in Western and Central Europe and
market shares of iodized household salt
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