Daily consumption of salt fortified with iodine is a proven effective strategy for prevention of IDD as reported in numerous scientific studies. Furthermore UNICEF and GAIN (The Global Alliance for Improved Nutrition), promote salt iodisation as it is the easiest and most effective way to secure iodine supply to the population. However, elevated sodium intake has been associated with a number of non-communicable diseases, (including hypertension, cardiovascular disease and strokes), and decreasing sodium intake may reduce blood pressure and the risk of associated health problems.
The balance between fortifying salt with iodine and reducing total salt intake may swing to lowering iodine intake below the recommended levels. The global trend to reduce sodium intake may require an increase in the amount of iodine added to salt in order to make up the difference. In addition iodisation of low sodium salt and other salt replacers is important to secure an adequate iodine intake.
This requires an active role of governmental organisation and food industry to monitor and eventually adapt the required salt iodisation in every country. If this is done in a pro-active way it can remove the potential conflict between the two mayor health issues, reducing sodium intake and securing an adequate iodine intake.
In countries that rely on iodised salt to supplement iodine deficiency in the diet, the reduction of salt will affect the daily intake of iodine. For instance there are conflicting aspects when on the on hand, bakers are encourage to reduce the quantity of salt in their products while on the other hand bakers are asked to replace regular salt with iodised salt in the baking of bread in order to increase daily iodine supply via bread. The table below shows how a reduction of salt used in baking, may reduce the amount of iodine consumption from bread by 50%.
Salt content (in flour) | 1.8% salt | 1.5% salt | 0.9% salt |
Iodine per slice of bread of 25gr (μg/slice) | 20 | 17 | 10 |
Iodine daily intake of 6–7 slices (μg/day) | 120–140 | 102–119 | 60–70 |
Decrease in iodine intake with decreased salt content of bread. | -15% | -50% |
Considering both the existing WHO policies about reducing the intake of salt and delivering adequate dietary iodine to populations, the World Health Organisation addressed this issue in 2014, providing a guideline [2] by suggesting the average recommended amount of iodine to add to salt, relative to an average daily salt consumption. These recommendations recognize that salt reduction and salt iodisation are compatible. Monitoring of salt intake and salt iodisation at country level will be needed to adjust salt iodisation over time as necessary, depending on observed salt intake in the population.
Estimated salt consumption *g/day |
Average amount of iodine to add, mg/kg salt (RNI + losses**) |
3 | 65 |
4 | 49 |
5 | 39 |
6 | 33 |
7 | 28 |
8 | 24 |
9 | 22 |
10 | 20 |
11 | 18 |
12 | 15 |
13 | 14 |
The challenge for development of low sodium salts has been taste; mostly a low sodium salt has a bitter taste due to replacer of sodium chloride. However, at this moment low sodium salts are available that are suitable for household and industrial applications and can facilitate the reduction of sodium in food without affecting the other functions of salt: taste and being the ideal carrier for iodine. This new generation of low sodium salts tastes nearly the same as sodium chloride Especially the iodisation of low sodium salts used in prepared foods is important, since in industrialized countries about 75% of sodium in the diet comes from manufactured foods and foods eaten away from home.
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