The introduction of iodized salt in America caused a boost in IQ worth 10 years. This was noticed later on when diseases such as goiter and mental retardation vanished. Credit goes to the amalgamation of iodine in the salt.
The fact that most of the salt found in the United States is iodized may have a vital link to the raised IQ of the population. As a first step towards preventing feeblemindedness, the intake of iodine is to be regulated. Thus when in the year 1924, iodized salt was presented to the public for consumption, mental health improved. IQ levels rose by 15 points in those most affected by mental retardation. That amounted to a leap of 3.5 points for each person. According to Business Insider, its a 10 years IQ boost for US gained by adding iodine to salt. The fact that IQ standards rise with the passing years was proved in fast-forward mode. However, while iodized salt has ended the scourge of mental deficiency in the West, in many Third World countries the selfsame version of salt is unavailable.
Iodine levels are high in sea water, but this particular form of water is not fit for consumption. And in the soil and common fresh water they are very low since they are leached by glaciers and other forces of Nature. The decade when iodized salt was very popular in the United States was the one whose IQ scores went up by 10 notches. Termed the Flynn Effect, this phenomenon counts for that guinea pig generation in particular. All signs of thyroid deficiency simply disappeared with the availability of iodized salt.