Question of the day:  Do U.S. food manufacturers need to use iodized salt?

Iodized Salt

Salt producers are a key partner in combating Iodine Deficiency Disorders (IDD) today throughout the world as agreed at a major IDD summit in Beijing ( 1    2 ).  Adding iodine to salt is a relatively simple task ( 1   2 ).  Many people erroneously assume that because salt iodization was achieved nearly a century ago, that the problem no longer exists.  Tragically, that's wrong.  In 1990, only about 20% of the world's households had access to iodized salt and were protected against Iodine Deficiency Disorders.  After a major push, access now exceeds 70%.  In October 2007, the American Thyroid Association hosted a symposium with valuable current information and capturing the excitement of the progress; it was entitled "A public health triumph in the making."  UNICEF Deputy Executive Director Kul Gautam delivered a stirring charge to delegates that captures not only the moral imperative of universal salt iodization, but includes an outstanding historical review of the entire issue. Gautam told delegates:

Scientists identified iodine as an element in the early 19th century and only 20 years later, French scientist J-B. Boussingault reported his conclusion that iodized salt would be an effective prophylaxis for goiter, stating "I am convinced that goitre would disappear...if the authorities made available in every district town...a depot of salt containing iodine."  Yet it took another century for "authorities in the U.S. and Switzerland to effectuate Boussingault's insight.

David Marine (1880-1976) is the "father" of iodized salt in the United States; fortifying salt pioneered the approach of adding nutrients to foods. As the result of research on endemic goiter and iodine deficiency by Marine and co-workers research, the Michigan State Medical Society, in 1924, launched a goiter prevention program using iodized salt.  It was the first example of a designed "functional food."  Medical science since has identified a far more serious threat than the cosmetic problem of goiter -- mental retardation.  The "hidden hunger" of iodine deficiency causes a 10-15% reduction in a population's IQ capability, mental retardation and cretinism.

In the United States, salt producers cooperated with public health authorities and made both iodized and plain salt available to consumers at the same cost. Newspapers urged people to use iodized salt for the prevention of iodine deficiency. The Michigan program was highly successful and iodized salt use quickly spread throughout the country. Ultimately, household use of iodized salt eliminated iodine deficiency in the North America.   In 1955, researchers reported that 75.8% of U.S. households used only iodized salt. The Salt Institute estimates that nearly 70% of the table salt sold in the United States is iodized.  The Centers for Disease Control and Prevention agree.  Continued public education is needed, however.  Recently, the National Academy of Sciences increased the recommended intake level for iodine and nutrition surveys show a small but steady erosion in Americans' iodine intakes.  The May 2006 ICCIDD IDD Newsletter contains an excellent article on the current status of iodine nutrition in the U.S. by Dr. Elizabeth Pearce of the Boston University School of Medicine.  The CDC also tracks iodine nutrition in the U.S.

Around the world, however, iodine deficiency remains a major  health problem ( 1   2   3   4   5 ).  The World Health Organization maintains a Global Database on Iodine Deficiency Disorders.  While natural sea salt has little iodine, fortifying salt is an effective means of increasing dietary iodine and is, in fact, the consensus solution ( 1   2   3   4 ).  Resources have been mobilized over the past decade.  The "virtual elimination" of IDD was identified as the highest  health priority for children at the 1990 World Summit for Children (described by the World Health Organization and UNICEF) and is the top service project of Kiwanis International.

The technology for iodizing or iodating salt is well known, readily available, and inexpensive.  One particular problem is that some countries lack high quality salt manufacturing and packaging technologies.  Assistance for these salt manufacturers is available in an outstanding publication of the International Council for the Control of Iodine Deficiency Disorders (particularly note chapters 5, 6, 10 & 11) and a series of how-to papers published by UNICEF's CEE/CIS and Baltic States Region.

Some food manufacturers fear using iodized salt will interfere with the color or taste of their products and affect consumer acceptance; for the most part, such concerns are insignificant.

Both potassium iodide and potassium iodate are used to add iodine to salt.  The U.S. Food and Drug Administration approves both potassium iodide and cuprous iodide for use in table salt. U.S. salt producers use potassium iodide at a level of 0.006% to 0.01% KI.  Daily Iodine intakes of 1,000 - 1,100 micrograms are safe for adults and children over 4 years of age, according to the World Health Organization (1994) and the U.S. National Academy of Sciences (2004) respectively.  Potassium iodate is preferred in some countries, particularly in tropical regions, because it is more stable than potassium iodide under hot, humid conditions. Loss of iodine from iodized salt produced and sold in the United States is not a concern because producers use moisture-proof packaging and add stabilizers; and storage conditions in the grocery distribution system are suitable. Table salt packaged and stored under proper conditions has an extended shelf life. 

Several countries, including France, Mexico and Switzerland, also add fluoride to table salt to prevent dental caries.  Salt double-fortified with iodine and iron is used in several other countries.

Global progress for the decade-long campaign in the 1990's was reported at the 8th International Symposium on Salt held in 2000 in The Hague; many of the papers are online.  That progress was recognized February 4, 2002, when UN Secretary-General Kofi Annan urged businessmen at the World Economic Forum to become "part of the solution" to world poverty and cited salt iodization as a prime example of public-private cooperation.  Current progress in the global campaign for iodine nutrition is tracked on a World Health Organization database.  With active cooperation by the Salt Institute (including a major effort by Salt Institute member Morton Salt*) and EuSalt, the Network for the Sustained Elimination of Iodine Deficiency  has been formed combining and coordinating the IDD eradication efforts of UNICEF, the World Health Organization, the ICCIDD (don't miss ICCIDD's regional website for South Asia), the World Bank, Kiwanis International,* *  the Program Against Micronutrient Malnutrition, and the Micronutrient Initiative (MI has useful information for salt producers in IDD-challenged countries   1     2 ).   Efforts are underway to create an International Iodine Laboratory Network.  The Network also intends to assess national salt iodization programs and verify hopeful claims of many nations that their campaigns to end IDD have achieved their objectives.   There is great progress to report.  Until the past decade, for example, China had the world's worst IDD problems; now it is a model for Asia and the world in its progress combatting iodine deficiency ( 1   2   3 ).  Mexico and much of Latin America have been particularly successful; the involvement of the salt industry has been an important contributor to this success in Latin America.   Brazil tracks salt iodization back to 1983.   A few of the national IDD eradication campaigns have online summary reports, including Pakistan, Nepal, Kenya and Nigeria.    India ( 1   2   3 ), in particular, is challenged with current problems.  So are the Balkans, Eastern Europe and the former Soviet Union ( 1   2 ).  Hopefully, within the next several years, the virtual elimination of IDD g;lobally can finally be proclaimed and efforts focused on sustaining that great achievement.  And sustaining iodine nutrition sufficiency cannot be assumed.   Even Western Europe, long thought iodine sufficient and Australia ( 1    2    3    4    5   6   7   8    9    10 ), longstanding in its proven achievement of iodine sufficiency, has disturbing evidence of recent problems.

The Salt Institute has prepared a global list of countries using iodized salt, together with the forms of iodine addition permitted and the required levels in salt.

Only a few companies produce the potassium iodide or potassium iodate used to iodize salt.  They include three Chilean companies, Industrias Quimicas de Yodo S.A. (INQUIM), Franmar Empresas Ltda. and IODINEX Chile Ltda. and one in India, Calibre Chemicals.

For further information, explore the Network members' websites (see above) or look at this bibliography. 

*   Want to see what Morton Salt has done to promote iodine nutrition?
** Want to see what Kiwanis International has achieved?

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